JP2007112582A - Paper feeding tray device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feeding tray device capable of feeding paper one by one by surely separating these paper even if stacking paper of generating high adhesive strength is set between transfer paper and transfer paper, and an image forming device. <P>SOLUTION: This paper feeding tray device A is constituted to make the tip in the feeding direction of the uppermost transfer paper arrive at a paper feeding position by upwardly inclining one side half in the feeding direction of this stacked transfer paper by stacking and storing the predetermined number of transfer paper put in a substantially horizontal state. Operation for returning to a horizontal state is continuously repeated by a predetermined frequency after inclining in the upward direction in the predetermined timing except for paper feeding time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper feed tray device and an image forming apparatus used in an image forming apparatus such as a facsimile, a printer, and a copying machine.

  Generally, a standard size cut sheet is provided to a user in units of a predetermined number of sheets packaged in one. That is, a predetermined number of transfer papers of the same standard size are stacked in a predetermined number such as 500 sheets, and the transfer papers stacked and assembled in this way are wrapped and packaged with a single packing paper and provided to the user. . For this reason, “cutting burr” or “sticking” may occur on the transfer paper. In other words, “cutting burr” occurs at the periphery of the transfer paper itself that is cut when it is cut into a standard size in the manufacturing process, and “sticking” means that when a predetermined number of transfer papers are packaged with packing paper, Glue used for joining overlapping portions of paper is generated by adhering to the transfer paper.

  In recent years, coated paper is frequently used to form a high image, and a strong “adhesion” between the coated papers may occur. That is, the coated paper is coated with a resin-based coat on the surface and covered with a uniform film, and the roughness of the coated paper surface is set to be minimal, Uniform and high flatness optimal for high images is ensured. Further, in a color image forming apparatus, sufficient whiteness and gloss can be secured on the surface of the coated paper, so that a vivid color image can be formed against this background, and high image quality can be achieved. On the other hand, when the coated papers are laminated by the above-described packaging or the like, it is difficult for air to enter between the paper surfaces of the laminated coated papers. "Adhesion" occurs.

  Such various situations often occur, and when using transfer sheets made of these cut sheets and coated sheets in the image forming apparatus, the sheets are originally separated one by one by the sheet feeding unit of the image forming apparatus. Even though the separated sheets must be conveyed toward the image forming unit, several to a dozen or more transfer sheets are overlapped by the above-mentioned “cutting burr”, “sticking”, and “contact”. There have been problems such as “double feeding” sent in a state of being fed and “non-feeding” in which the carrying force is insufficient due to an increase in carrying load. That is, the paper feeding unit has, for example, a paper feeding tray in which transfer sheets of the same size are stacked and stored, and the paper feeding unit feeds the paper feeding tray to the conveyance path to the image forming unit in units of one sheet.

  These “double feed” and “non-feed” not only lower the mechanical quality of the paper feeding device, that is, the mechanical performance quality of the device, but also damage the mechanical components that make up the paper feeding device due to an increase in load. Therefore, the transfer paper that is improperly conveyed cannot be reused, and the transfer paper is wasted. For this reason, loss of supplies as repair parts and consumables occurs, and it is necessary for the sheet feeding device to prevent the occurrence of “double feed” and “non-feed”.

  When “cutting burr”, “sticking” or “adhesion” occurs, the force required to separate the transfer papers is generally about 100 g. The required force tends to increase. In other words, when using transfer paper coated on both sides in a humid environment, the force required for separation doubles because moisture stays on the surface of the paper and the degree of sealing between the papers increases. There are also coated papers of up to 700-800 g.

  In the paper feeding / separation unit of the paper feeding device, a friction separation method is often used in order to cope with a wide variety of paper types. As the friction separation method employed in the paper feeding device in this way, cost, installation space, etc. Any of the methods such as fixing the separation member, rotating it slower than the paper advance speed, or rotating it back in the counter-conveying direction due to restrictions on product standards Is selected. Thus, even if there are various types of friction separation methods, the basic operation principle is the same, and it is set so as to have a force relationship of “conveying force> blocking force> inter-paper adhesion force”. Separation processing is performed on paper. In other words, the conveyance force acting on one transfer sheet to be separated and fed is the largest, and the blocking force acting on other transfer sheets other than the one sheet by the separating member is larger than the conveyance force. It is small and larger than the adhesion between papers. Therefore, since the force relationship is set in this way, at the time of feeding, one transfer sheet to be fed continues to move in the transport direction against the inter-sheet adhesion force, but at least other than this The other transfer paper is stopped against the inter-sheet contact force, and the two are separated, and only one transfer paper is fed in the transport direction and fed.

In addition, when the paper is fed, a predetermined fixed guide member is disposed at a predetermined location on the upstream side of the transport member on the transport path, and the front end in the transport direction of the entire sheet transported by a predetermined number of sheets is in relation to the paper surface. Various types of paper feeding devices that prevent double feeding of paper by making contact in a state of being aligned on a substantially oblique line, instead of being in contact with a predetermined conveying member in a state of being aligned on an orthogonal line are known ( For example, see Patent Documents 1 to 3.)
Further, when the paper is fed, a predetermined fixed guide member is provided, and the entire sheet transported by a predetermined number of sheets by the fixed guide member is placed in a direction perpendicular to the paper surface of the sheet at a position before the transport member. Various paper feeding devices that are in contact with a conveying member while being curved are known (see, for example, Patent Documents 4 and 5).

  Further, there is known a sheet conveying apparatus in which a stacking tray for stacking sheets is configured by two small trays, and a dedicated mechanism for individually moving these two small trays up and down is provided (for example, patents). Reference 6). Therefore, according to this sheet conveying apparatus, a step is generated between both small trays, and the sheets on the stacking tray can be bent repeatedly, so that the influence of the adhesion force between the sheets is eliminated, and double feeding is performed. It is said that the stacking tray or the sheet can be stably conveyed without causing it.

  As a paper feed separation system other than the above, there is also known an air separation system in which air is blown between the transfer paper and the transfer paper by blowing air to the side surface of the transfer paper bundle (for example, Patent Documents). 7). In other words, the paper feeder using this air separation system allows the stacked paper to be placed on the bottom plate of the paper feed tray and stored in the paper feed tray, and moved up and down by moving the bottom plate up and down. An air flow path is formed in the vicinity of the side edge of the stacked paper, and an air blocking means for blocking air to the stacked paper is provided so that a boundary between a region where the stacked paper is blocked and a region where the stacked paper is not blocked is formed. The boundary of the air flow path is sequentially moved with respect to the stacked sheets by relative movement of the air blocking means and the stacked sheets, and the air is sequentially flowed between the stacked sheets. Therefore, according to this paper feeding device, the air flow path is formed so as to sequentially move between a large number of sheets as compared with the case where a new air flow path is formed at a time between a large number of sheets. As a result, a large amount of air flows into the air flow path that is formed, which increases the effect of separating the paper. Since the path is moved relative to the loaded paper, the above-described air flow path is changed without providing air moving means, direction changing means, or movable means for moving the entire air blowing means. It is said that the apparatus configuration is relatively simple.

  On the other hand, unlike these, there is a method for allowing the user to perform an artificial operation. In other words, for example, the instruction for operating the machine before the transfer paper is set in the paper feed tray by the user with the instruction manual of the machine or the attached decal for instructing the operation, and then instructing the user to set the transfer paper. There was also.

JP-A-4-303347 (pages 3-4, FIG. 1) Japanese Patent Laid-Open No. 11-20958 (pages 3 to 4, FIG. 1) Japanese Patent Laid-Open No. 11-165898 (pages 3 to 4, FIG. 1) Japanese Patent Laid-Open No. 11-292316 (pages 3 to 4, FIG. 1) Japanese Unexamined Patent Publication No. 2000-16607 (pages 3-4, FIG. 1) JP-A-4-327433 (pages 3-5, FIG. 1) Japanese Patent Laid-Open No. 2003-176051 (pages 3 to 5, FIG. 1)

  However, in the configuration using the above-described frictional separation method, the general adhesion force (about several tens of grams) is imposed due to cost constraints and the life of parts including the positioning of the paper feeding device as a device constituting the image forming apparatus. ), And it is difficult to reliably separate paper on which “cutting burr”, “sticking”, and “adhesion” have occurred.

  In any of the configurations of Patent Document 1 to Patent Document 5 described above, the sheets are merely shifted from each other in the paper surface direction, and at least the sheets are in contact with each other. On the other hand, there is also a press contact, and even if the adhesion force between the sheets can be reduced, the reduction effect is insufficient. For example, particularly when the above-mentioned coated paper is used and “cutting burr” or “sticking” occurs, even with these configurations, the ability to reduce the adhesion to the coated paper is insufficient, and the May cause defects.

  Further, in the configuration of Patent Document 6 described above, a dedicated mechanism for individually moving up and down the two small trays constituting the stacking tray is provided, and the two small trays are arranged in a single tray during feeding. It is necessary to move up and down and position it at a predetermined paper feed position, which complicates the structure of the apparatus and the control structure, leading to an increase in cost and failure of not only the paper feed mechanism but also this dedicated mechanism. There is a possibility that maintenance is troublesome.

  Further, as in the configuration of the above-mentioned Patent Document 7, the air separation method that blows and separates air is difficult to blow stable air on paper, and air blowing is used on paper with low rigidity such as thin paper. The paper is blown out by this, and the position in the paper feed tray is misaligned, the end is bent, and there are side effects such as noise caused by the blowing sound. It is not used in paper devices, but is used only in industrial machines where the conditions of paper types are limited by ultra-large printers and noise can be tolerated.

  In addition, it is not possible to expect the effect of the sabaki work because the work of the sabaki work is caused by the variation of individual work of the user, the power of the work, and sometimes a messy work, but rather the folding of the transfer paper occurs. Due to concerns about side effects, it is not recommended for general office equipment.

  Therefore, the present invention solves the problems of the conventional ones as described above, and even when a laminated paper having a high adhesive force between the transfer paper and the transfer paper is set, these are surely separated, and 1 An object of the present invention is to provide a sheet feeding tray device and an image forming apparatus that can feed sheets one by one.

  In order to solve the above-mentioned problem, the invention according to claim 1 is configured such that a predetermined number of transfer sheets that are substantially horizontal are stacked and stored, and one half of the transfer sheets in the feeding direction is inclined upward. In the paper feed tray device configured to reach the paper feed position at the leading edge of the uppermost transfer paper in the feed direction, at a predetermined timing other than the time of paper feed, an operation of returning to the horizontal state after tilting upward is performed. , Continuously repeated a predetermined number of times.

  According to a second aspect of the present invention, there is provided a paper feed tray for storing the transfer paper, and a length that is substantially half of the length in the feed direction of the transfer paper, and the rear end in the feed direction is the feed tray. A bottom plate as a swing fulcrum, a drive unit that swings and drives the bottom plate to move up and down, and when the bottom plate is raised, the uppermost sheet of transfer paper loaded on the bottom plate is fed and conveyed An upper limit detection sensor that detects that the position has been reached, and a control unit that controls the drive unit to a predetermined level, wherein the control unit is configured to feed paper when it is not designated. The drive unit is controlled to repeat a plurality of operations in which the bottom plate is swung and the transfer sheet loaded on the bottom plate is lifted and lowered substantially continuously.

  According to a third aspect of the present invention, in the second aspect, the control unit includes a storage unit that counts a time taken to drive the bottom plate to drive up and down and stores the time, and the upper limit detection sensor Based on this detection, the time taken to raise the bottom plate is stored in the storage unit, and the lower limit for lowering the bottom plate after rising is the time stored in the storage unit.

  According to a fourth aspect of the present invention, there is provided a paper feed tray for storing transfer paper, and a length that is substantially half of the length in the feed direction of the transfer paper, and the rear end in the feed direction is the paper feed tray. A bottom plate as a swing fulcrum, a drive unit that swings and drives the bottom plate to move up and down, and when the bottom plate is raised, the uppermost sheet of transfer paper loaded on the bottom plate is fed and conveyed An upper limit detection sensor for detecting that the position has been reached, a lower limit detection sensor for detecting that the bottom plate is at the lower limit, and a control unit for controlling the drive unit to a predetermined level, the paper feed tray device comprising: The control unit performs a control of repeatedly repeating the swinging motion of raising and lowering the bottom plate a plurality of times based on the detection of the upper limit detection sensor and the detection of the lower limit detection sensor when paper feed conveyance is not designated. is doing.

  According to a fifth aspect of the present invention, in the fourth aspect, the start timing of the control is when a paper feed tray loaded with transfer paper is set in the apparatus main body.

  According to a sixth aspect of the present invention, in the fourth aspect, the start timing of the control is when the power of the apparatus main body is turned on.

  According to a seventh aspect of the present invention, in the fourth aspect, the start timing of the control is when the apparatus main body enters the preheating mode.

  According to an eighth aspect of the present invention, in any one of the second to seventh aspects, the oscillating motion continues without a gap when moving from ascending to descending, and for a certain period of time when shifting from descending to rising. It is empty.

  In a ninth aspect of the present invention, in any one of the second to eighth aspects, the swinging motion has a lowering speed than a rising speed.

  According to a tenth aspect of the present invention, in any one of the second to ninth aspects, the power source that supplies power to the drive unit is one of two types of power sources: a power source voltage when rising and a power source voltage when falling Any one of the above can be output, and the drive unit is driven by a higher power supply voltage when descending than when ascending.

  According to an eleventh aspect of the present invention, an image forming apparatus includes the paper feed tray device according to any one of the first to tenth aspects.

  A twelfth aspect of the present invention is the image forming apparatus according to the eleventh aspect, wherein the image forming apparatus is any one of a copying machine, a printer, and a facsimile, or a combination machine of some of them.

  Since the present invention is configured as described above, the paper feed tray device can reduce the adhesive force generated between the overlapping transfer papers, so that the overlapping transfer papers can be easily and reliably supplied during paper feeding. The transfer paper can be fed and fed in units of one sheet.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic front view showing the overall configuration and peripheral members of the paper feed tray apparatus of this embodiment, and FIGS. 2A to 2C illustrate the unique actions of the paper feed tray apparatus, respectively. It is a conceptual diagram for.

  That is, the paper feed tray device is installed at an appropriate place in the image forming apparatus (not shown), and when the image forming apparatus forms an image, the paper feeding operation is performed in conjunction with the image formation, toward the image forming unit (not shown). A sheet-like recording material (hereinafter, referred to as a sheet S) to which an image formed by an image forming unit of an image forming apparatus such as a transfer sheet is transferred and fixed one by one is sent out. The image forming apparatus is a general office machine installed and used in an office, and is a copying machine, a printer, a facsimile machine, or a combination machine combining some of them.

  The paper feed tray device A includes a paper feed tray 1 that stores a predetermined number of sheets S, and a bottom plate that is provided with a swing fulcrum at one end and is pivoted around the swing fulcrum. 2 and a drive unit 3 that uses an electric motor as a drive source to drive the bottom plate 2 to a predetermined inclination to raise the paper S set on the bottom plate 2 to a paper feed position above the paper feed tray 1, and to raise the drive unit 3. An upper limit detection sensor 6 for detecting the position of the uppermost sheet S, a lower limit detection sensor 7 for detecting the lower limit position of the bottom plate 2, a control unit 5 for raising the bottom plate 2 to its upper limit and then lowering it to the lower limit, and driving A power supply 4 that arbitrarily supplies power (motor driving power) to the unit 3 and that can switch the voltage of the supplied power to two types of low voltage and high voltage is provided.

  In other words, the paper feed tray device A places the paper feed tray 1 in which a predetermined number of sheets S are stacked and stored, and a length approximately half the length in the feed direction of the paper S. A bottom plate 2 having the rear end in the feed direction as a swing fulcrum with respect to the paper feed tray 1, a drive unit 3 that swings and drives the bottom plate 2 to move up and down, and a stack when the bottom plate 2 is raised The upper limit detection sensor 6 for detecting that the uppermost sheet of the sheets S has reached the optimum position for feeding and conveying, the lower limit detection sensor 7 for detecting that the bottom plate 2 is at the lower limit, and the drive unit 3. A control unit 5 that controls the driving unit 3 to an arbitrary time or amount and a driving direction thereof, and the control unit 5 controls the upper limit when the paper feed conveyance is not designated. Based on the detection of the detection sensor 6 and the detection of the lower limit detection sensor 7, the bottom plate 2 is raised. It has a control to repeat a plurality of times in succession oscillating motion to lower the.

  Note that reference numeral 10 in the figure is fixedly disposed so as to be rotatable on a horizontal axis (not shown) with a predetermined gap distance from the upper opening side of the paper feed tray 1 in the conveying direction and with respect to the upper opening. At least at the time of paper feeding, a rotational driving force is transmitted from a driving source such as a motor (not shown) to the shaft of the calling roller 10 at the time of paper feeding, and the counter roller rotates counterclockwise in FIG. The sheet S in the sheet feeding tray 1 that rotates and contacts the calling roller 10 is pulled out in the transport direction and advanced. Reference numerals 11 and 12 denote separation units composed of a sheet feeding roller and a separation roller that are vertically opposed to each other so that the nipping unit is positioned on an extension line in the sheet conveyance direction by the calling roller 10. These rollers 11 and 12 cooperate to separate the sheets S and S drawn from the sheet feed tray 1 one by one, and only the separated sheet S is fed to the sheet feed roller 11 and the separation roller. It is configured to send it out to a conveyance path (not shown) provided downstream of the 12 roller pairs.

As a separation method of the separation unit, for example, an FRR paper feeding method which is a return separation method is adopted. In this FRR paper feeding system, a paper feeding roller 11 that is rotationally driven in the forward direction in the conveying direction and a lower side of the paper feeding roller 11 are in contact with each other, and a rotational driving force in the reverse rotational direction is provided via a torque limiter. A separation roller 12 that is transmitted and driven in reverse is provided. The upper sheet feeding roller 11 is always in contact with the upper surface of the sheet S to be sent to the conveyance path, while the lower separation roller 12 is Regardless of whether there are two or more sheets, the sheet S is in contact with the lower surface of the sheet S in contact with the sheet feeding roller 11. In other words, in this configuration, the separation roller 12 is given a weak torque in the reverse rotation direction to the paper feed roller 11 via the torque limiter.
Therefore, when the separation roller 12 is in contact with the paper feed roller 11 or when one sheet S enters between the rollers 11 and 12, the separation roller 12 rotates with the paper feed roller 11. That is, due to the action of the torque limiter, for example, the separation roller 12 slips with respect to the reverse roller drive shaft, and, similar to the paper feed roller 11, the separation roller 12 rotates in the forward direction that advances in the paper feed direction.
On the other hand, when the separation roller 12 is separated from the paper supply roller 11 or when two or more sheets S enter between the two rollers 11 and 12, the separation roller 12 rotates in the reverse direction. For this reason, when the multi-feed sheets S and S enter, one sheet S in contact with the sheet feed roller 11 as the top sheet S among the sheets S stacked and stored in the sheet feed tray 1 remains as it is. While proceeding in the transport direction, other sheets S that are in contact with the separation roller 12 other than the one sheet S are returned to the sheet feeding tray 1, thereby preventing the sheets S from being double-fed.
The separation method used for the separation unit is not limited to the above-described FRR paper feeding method, and other separation methods having an appropriate configuration may be used.

  In addition, the sheet feeding tray device A stores the sheets S stacked in the sheet feeding tray 1, and the bottom plate 2 that forms a part of the floor surface of the sheet feeding tray 1 serves as the driving unit 3 during the sheet feeding operation. Is driven to incline upward to push up one half of the laminated sheet S on the forward side in the conveying direction, and the leading end of the laminated sheet S in the conveying direction reaches the sheet feeding position in contact with the calling roller 10. I am doing so.

That is, the paper feed tray 1 is formed in a substantially flat box shape having an upper opening having a floor surface capable of storing the maximum size paper S handled by the image forming apparatus and a depth capable of storing a predetermined number of sheets. The paper feed tray 1 is pulled out of the image forming apparatus and replenished with paper S of the same size as the stored paper S, or can be replaced with paper S of various sizes below the maximum size. Is stored in the image forming apparatus in a posture that is substantially horizontal.
Further, the paper feed tray 1 is an end for storing these various sizes of paper S in a stacked manner with the peripheral edges of the leading edges in the substantially right direction in the drawing aligned on substantially the same vertical plane. It has a fence 1A and a side fence (not shown). That is, all the leading edges of the stored sheets S, S are brought into contact with the inner wall surface shown on the right side of the sheet feed tray 1 as the front reference wall located in the front in the transport direction. The position of the rear edge of all the rear edges is appropriately pressed by the end fence 1A and the side edges of all the sheets S, S that are in the width direction with respect to the conveying direction are appropriately pressed by a pair of side fences. The sheets S and S of various sizes stored in the above are aligned in a predetermined manner.
The end fence 1A is erected on the floor surface of the paper feed tray 1 and holds the erected posture on the floor surface, and is slidable along the conveyance direction indicated as the left-right direction in the drawing. According to the size of the paper S actually stored in the paper feed tray 1, it is slid with the vertical wall in contact with the rear end of the stored paper S in the transport direction. Further, it does not interfere with the end fence 1A, and is similarly erected with respect to the floor surface and maintains the erected posture on the floor surface. In addition, a pair of side fences that can be slid symmetrically in the width direction are provided, and these side fences are in contact with the peripheral edges on both sides of the paper S. Accordingly, by adjusting the positions of the end fence 1A and the side fence with respect to the floor surface of the sheet feeding tray 1, a plurality of sheets S and S of various sizes are opposed to each other on the basis of the front reference wall. The upper and lower surfaces can be stored in an aligned manner so as to be in contact with each other.

  The bottom plate 2 is formed in a substantially flat plate shape with a plate thickness that secures a strength that can withstand the load caused by a half of one side of the sheets S, S laminated a predetermined number of times, and constitutes a part of the floor surface of the paper feed tray 1. It is provided to place one half of the leading end side of the sheet in the transport direction. The bottom plate 2 is centered around the horizontal axis on the paper feed tray 1 through both ribs that are connected to the peripheral edges on both sides in the transport direction and on both sides with respect to the transport direction. It is pivotally supported. Therefore, the bottom plate 2 is conveyed from the state of a substantially horizontal posture which is a part of the floor surface of the paper feed tray 1 with the horizontal axis as a pivot point of the swing center, which is shown as the right end in the figure. It can be swung within the range up to the state of the upward inclined posture with the tip side in the direction positioned upward.

Below the bottom plate 2, there is a lifting lever 8 that is oscillated and driven by a rotational driving force in a predetermined direction output from the drive unit 3, and that pushes the lower surface of the bottom plate 2 upward at its tip to drive it to tilt upward. , Provided.
That is, the raising lever 8 is housed in a recess having a predetermined shape formed at the bottom of the sheet feeding tray 1 and is formed in a long plate shape having a predetermined length, and the raising lever 8 has a base end thereof. Is fixed to a horizontal shaft 8A that is pivotally supported at a location facing the substantially central portion of the bottom plate 2 in the recess, and the horizontal shaft 8A is connected to the horizontal shaft 8A as a drive unit 3 via an appropriate reduction gear train. The rotational driving force output from the electric motor is connected to the output shaft of the electric motor so as to be able to transmit. Accordingly, a rotational driving force in an arbitrary rotational direction is transmitted from the driving unit 3 as a rotational driving source and rotated to a predetermined angle, and the ascending lever 8 occupies an angular position that is inclined with the horizontal axis 8A as the rotational center. Is driven to swing. As a result, the tip of the raising lever 8 pushes up the bottom plate 2 and can move up so as to keep at least the one side periphery of the uppermost surface of the sheets S, S placed and stacked on the bottom plate 2 at a predetermined height position.
In addition, a lock mechanism (not shown) is provided along with the horizontal shaft 8A, or a lock mechanism (not shown) is provided on the driving force transmission system path, and the electric motor itself has a lock function. Even when the power supply is stopped, the ascending lever 8 is configured to maintain its tilted posture so that the current swing angle position can be maintained.
Note that the electric motor as the drive unit 3 is connected by wiring so that power is supplied from the power source 4, and for example, a DC motor whose rotational speed of the rotational driving force output is high according to the level of the supply voltage is used. It has been.

The control unit 5 is configured by mounting appropriate electrical components such as a memory and a CPU (information processing processor) on a circuit board, and measures the storage function as a storage unit and the passage of time from an arbitrary time point as a timer. Control that has a timekeeping function, and performs coordinated control in which the operations of the respective parts are linked in order to perform the above-described paper feeding operation, and control that causes only the bottom plate 2 on which one half of the loaded paper is placed to swing in a predetermined manner Thus, the adhesion force acting between the stacked sheets is reduced so that the sheets can be easily separated. That is, the control unit 5 is wired to the upper limit detection sensor 6 and the lower limit detection sensor 7 so that the detection signals output from the respective inputs can be input, and the power source 4 can transmit the command signal transmitted from the control unit 5. Wired to
The control unit 5 may be provided separately from a control unit that performs normal sheet feeding operation only for drive control for facilitating separation of the overlapped sheets. A control unit for controlling the devices in each unit may also be used. In any case, the control unit 5 is wired so as to acquire detection signals from the upper limit detection sensor 6 and the lower limit detection sensor 7 and transmit a command signal to the power supply 4, and further determines the start timing of the predetermined control. It is assumed that wiring connection is performed so that a signal indicating information necessary for this is obtained from the control unit of the image forming apparatus.

  The power supply 4 is configured to output electric power having a predetermined polarity and a predetermined voltage based on a command signal from the control unit 5 at an arbitrary timing and supply the electric power to the driving unit 3. In other words, the power supply 4 is based on a command signal from the control unit 5 and has a positive polarity that causes the motor to perform normal rotation from a neutral position where no power is output from the switching element or switch circuit including the built-in switching transistor. Either a connection position for supplying a drive power supply that outputs power at a predetermined voltage, or a connection position for power supply that supplies a lower drive voltage that has a reverse polarity that causes the motor to reversely rotate and outputs power that is higher than the predetermined voltage. Switching operation is carried out alternatively.

The upper limit detection sensor 6 is capable of detecting whether or not the uppermost sheet of the paper S placed on the bottom plate 2 has reached the paper feed position as the bottom plate 2 is driven up. It is a position detection sensor fixedly installed on the tray device main body side, and is electrically connected to the control unit via wiring.
That is, for example, the upper limit detection sensor 6 is a pressure sensor with an appropriate configuration that detects a change in axial pressure on a shaft that rotatably supports the calling roller 10, and the pressure sensor is configured such that the calling roller is in contact with the paper S. It has a sensitivity capable of distinguishing and detecting a state in which the axial pressure is increased or decreased when the calling roller 10 is in contact with the raised paper S from a non-axial pressure state, and at least indicates that the calling roller 10 is in contact with the paper S A signal is output.
Accordingly, the upper limit detection sensor 6 has detected that the uppermost sheet of the sheets S, S stacked and placed on the upper surface of the bottom plate 2 has caused the leading end in the transport direction to reach the sheet feeding position, that is, sheet feeding proceeds. When the number of stacked sheets decreases and the distance from the upper surface of the bottom plate 2 to the uppermost paper is not constant but variable, the bottom plate 2 causes its one end to reach the upper limit position in the sense that the uppermost paper has reached the paper feeding position. When the bottom plate 2 itself is inclined upward, a detection signal indicating that the bottom plate 2 has reached the upper limit position is transmitted to the control unit via the wiring. For this reason, when the bottom plate 2 is driven to swing so as to incline upward, the upward inclination angle corresponding to the number of sheets actually placed on the bottom plate 2 at that time is obtained, so the lower limit is Although it is always constant, as the number of sheets decreases, the inclination angle increases and the range is expanded as a swing angle range.

The lower limit detection sensor 7 is a position detection sensor installed in the paper feed tray 1 so as to detect whether or not the bottom plate 2 has reached the lower limit position, and is electrically connected to the control unit via the wiring. Yes.
That is, the lower limit detection sensor 7 is a position detection sensor having an appropriate configuration for detecting the tip position of the bottom plate 2 in the transport direction. For example, when the bottom plate 2 is in a horizontal posture, the tip is placed in a detection range, and the paper is fed. The tray 1 is fixedly installed.
Accordingly, the lower limit detection sensor 7 generates a detection signal indicating that the bottom plate 2 has reached the lower limit position when the bottom plate 2 has its one end reached the lower limit position and the bottom plate 2 itself is in a substantially horizontal posture. Then, the data is transmitted to the control unit via the wiring.
The lower limit detection sensor 7 is not limited to the configuration of the position detection sensor described above, and may be an angle position detection sensor provided along with a shaft that supports the bottom plate 2 or a shaft of the lift lever 8. In this case, a predetermined angular position of the shaft corresponding to the posture of the bottom plate 2 of the shaft is detected.

Next, an operation for facilitating separation of stacked sheets in the sheet feeding tray apparatus A configured as described above will be described.
First, as a predetermined timing other than paper feeding, when a predetermined number of sheets S and S are set in the paper feeding tray 1 and the paper feeding tray 1 is inserted into the image forming apparatus, or the power of the image forming apparatus is turned on. When either the start-up preparation operation of the apparatus is started immediately after being turned on or when the image forming apparatus enters the preheating mode, the control unit 5 applies a low voltage to the power supply 4 to the driving unit. 3 outputs a command signal instructed to be supplied to the drive unit 3, and the drive unit 3 starts operation at a slow drive speed according to the low voltage and raises the bottom plate 2 until the upper limit detection sensor 6 detects the uppermost sheet.
Accordingly, the stacked sheets stored in the paper feed tray 1 are shown in FIG. 2 (b) in which the bottom plate 2 is inclined upward from the stacked state shown in FIG. 2 (a) in which the bottom plate 2 is in the horizontal posture. As shown in the enlarged view in FIG. 2 (b), the stacked sheets are placed on the lower surface of the upper sheet on the lower surface of the upper sheet at the leading end in the transport direction. The upper surface does not match and is always shifted by a predetermined amount along the surface direction.

  When the upper limit detection sensor 6 detects the upper limit, the control unit 5 outputs a signal instructed to supply the power source 4 with a high voltage to the drive unit 3 and a signal instructed to reverse the rotation direction. Upon receiving these instructions, the power supply 4 starts supplying a high-voltage and reverse-polarity power supply to the drive unit 3, and the drive unit 3 starts operating at a high drive speed corresponding to the high voltage. The bottom plate 2 is lowered at a high speed until the lower limit detection sensor 7 detects the lower limit of the bottom plate 2.

  Accordingly, the stacked sheets S and S try to gradually return from the state shown in FIG. 2B to the stacked state shown in FIG. 2A, but at least as shown in FIG. In addition, an air layer that reduces the adhesion between the stacked sheets S and S passes through the process of interposing between the sheets. That is, the stacked sheets S and S placed on the bottom plate 2 do not descend following the lowering of the bottom plate 2, but the peripheral edges of the respective sheets S and S are the sides installed in the paper feed tray 1. Since it is in contact with the fence and the front reference wall, a frictional resistance that hinders the movement of the paper S in the attachment direction occurs, and the attachment is not completed immediately. That is, when the bottom plate 2 is driven to descend, the stacked sheets S and S are not supported by the bottom plate 2 and are temporarily separated. For this reason, in the process in which the sheet S naturally settles at a descending speed in which the bottom plate 2 is rapidly lowered and the frictional resistance and its own weight are balanced, as described above, before the settlement process, as described above. Also, since the sheets S and S are already shifted from each other by a predetermined amount in the surface direction and the adhesion between the sheets S and S is weakened, the half on the one side located in the forward direction in the transport direction is deeper about the substantially central portion. Also from the bending, it is possible to form a gap, that is, to generate an air layer between the surfaces of the sheets S, S opposed to each other at the substantially central portion in the half on one side.

When the lower limit detection sensor 7 detects the bottom plate 2, the control unit 5 temporarily stops the reverse rotation operation of the drive unit 3 that is a high-speed descent drive of the bottom plate 2, and starts rising at a low voltage after a certain time. A signal is output, and the operation of rising and lowering is repeated a predetermined number of times. In other words, the swinging motion in which the bottom plate 2 rises and then descends is repeated a predetermined number of times.
Therefore, if an air layer can be interposed in a part of the sheet surface area facing each other in the half of one side of the sheets S, S positioned on the bottom plate 2 in this way, the air layer can be spread to another area, Even if it stays in the partial area, the position occupied by the partial area with respect to the entire area can be moved, so that the air layer formed in a part can be transferred and spread. That is, in the process in which the sheets S and S return to a stationary state and return to a horizontal posture, it can be expected that the effect of reducing the adhesion is spread not only on one half but also on the entire area of the sheet surface.

Even if the control unit 5 determines whether or not each of the above-mentioned predetermined timings, the control unit provided in advance in the image forming apparatus determines and notifies the control unit 5 of the determination. Or either.
Specifically, the predetermined timing other than the time of paper feeding, that is, the timing for starting the above-described series of operation control, is basically basically that other than the timing when the image forming apparatus is completed by the operation of the image forming apparatus. The determination is made based on detection information from sensors that detect the state of each unit that the apparatus has in advance.
For example, when the predetermined number of sheets S are set in the paper feed tray 1 and this paper feed tray 1 is inserted into the image forming apparatus, the judgment is made when the following conditions are satisfied. Suppose that That is, for example, based on a detection signal from a sensor that detects whether or not the paper feed tray 1 has been set, a condition is met when the paper feed tray 1 is once set to an unset state and then returned to the set state. May be satisfied. On the other hand, for example, a paper feed device constituting a part of the image forming apparatus has a signal indicating the absence of paper from a sensor that detects the presence or absence of paper in the paper feed tray 1, and then the paper feed tray 1. A sensor that detects whether the door has been opened and closed, and a sensor that detects the presence or absence of the paper, from a sensor that detects an open / closed state of the open / close door that the image forming apparatus or paper feeding apparatus that covers the internal member of The condition may be satisfied when the signals indicating the presence of the sheet and the signals indicating that the sheet is present are acquired in the above order. Furthermore, you may combine these suitably.

  Further, for example, when the image forming apparatus start-up preparation operation is started immediately after the image forming apparatus is turned on, or when the image forming apparatus enters the preheating mode, the complete image formation in the image forming apparatus is performed. Since it is the operation of the apparatus itself, the determination made by the control unit of the image forming apparatus may be followed as it is. That is, for example, as a part of a command signal transmitted from the control unit to each unit, the control unit of the image forming apparatus transmits a notification indicating a preparatory operation or a preheating mode to the control unit 5 to notify the control unit. Reference numeral 5 denotes the timing at which these signals are received as the above-described control start timing. On the other hand, the control unit 5 may determine that the time immediately after the power is turned on is the time when the start-up preparation operation is started, and may be the above-described control start timing.

  On the other hand, if the image forming apparatus shifts to the preheating mode and there is an instruction to start the image forming operation while the paper feed tray apparatus A is performing the above operation, at least the fixing unit performs preheating. Until the transition from the state to the fixable state is completed, the sheet feeding tray device A continues the above operation and completes the number of times as appropriate, and shifts to the normal sheet feeding operation when the bottom plate 2 reaches the lower limit position. Either the above operation is immediately interrupted, the bottom plate 2 is returned to the lower limit position, and then the normal paper feeding operation is started.

  As described above, according to the paper feed tray device of this embodiment, even when a plurality of transfer papers or the like having a high adhesion force are set on the bottom plate by the above-described repetitive operation, at least the conveyance advance The half of one side of the paper positioned in the direction can be bent a plurality of times and as much as possible. In particular, even if the number of sheets placed on the bottom plate decreases with the progress of paper feeding, the swing angle range is expanded following this, and one side half of the paper is multiple times and as much as possible. It can be bent more fully. For this reason, it is possible to cause a gap between the overlapping sheets and to feed air between the surfaces of the sheets that are in contact with each other, thereby reducing the adhesion force between the sheets. For this reason, even when other sheets are transported together with the uppermost sheet from the sheet feeding position during feeding, the adhesion is reduced, so that the separation unit can reliably separate the sheets one by one and separate them one by one. The sheet can be fed and fed to a conveyance path downstream of the unit.

  Also, the vertical movement of the bottom plate is performed immediately after the image forming apparatus is turned on, during the start-up preparation operation of the apparatus, so that the operation for reducing the adhesion between the sheets is performed. Even if a copying operation is requested as an image forming operation immediately after the image forming apparatus is started up, the paper feeding operation is not hindered due to the adhesive force, and the first feeding operation can be performed. The sheets S can be reliably separated and fed one by one.

Further, when the image forming apparatus completes its image forming operation and enters a predetermined preheating mode, the image forming apparatus can further reduce the adhesion force generated between the overlapped sheets, and can perform image formation. There is no need to apply a load to the power supply built into the device.
That is, the image forming apparatus includes a fixing unit having an electric heat source that heats and pressurizes the paper on which the image has been transferred in order to fix the image transferred onto the paper on the paper. A predetermined power source is supplied so that the fixing unit raises the temperature to a predetermined temperature for fixing. For example, the image forming apparatus completes the image forming operation and the next image forming operation is not started. When a predetermined time has elapsed, the operation of the image forming apparatus is shifted from the normal image forming operation mode to the preheating mode, and in this preheating mode, the standby temperature at which the fixing unit can quickly return to the fixing temperature is maintained. In order to reduce power consumption compared to the normal operation mode, power can be saved by intermittently supplying power to the fixing means or supplying power sufficient to maintain the standby temperature. I have to.
Accordingly, during such a preheating mode interposed between one image forming operation and the next image forming operation, the sheet feeding tray device operates to reduce the adhesion force generated between the stored stacked sheets. Therefore, depending on the time interval between image forming operations, the pre-heat mode is entered and the above operation is always performed before the next image forming operation. , And can be provided in a state in which the adhesion is further reduced. On the other hand, during the preheating mode in which power consumption is reduced as compared with the normal operation mode, the sheet feeding tray device supplies power to its drive unit and performs the above-described operation. Therefore, the sheet feeding tray device is built in the image forming apparatus. It is not necessary to apply an extra load to the power supply.

Furthermore, when the bottom plate is lowered, the paper that is the transfer paper in the tray is in contact with the side fence and the entire reference wall that regulate the position of the paper, so it does not fall off immediately, so the top paper is surely By waiting for the bottom plate to rise until it falls, it is possible to reliably reduce the adhesion between the bottom paper and the top paper.
That is, in the swing motion, when the transition from the ascending motion to the descending motion is performed, both motions are continuously executed without being interrupted. The ascending movement is started after a predetermined elapsed time for separating the movement. Therefore, in the process where the paper settles as the bottom plate is lowered, the periphery of the paper is in contact with the side fence and the front reference wall installed in the paper feed tray. A frictional resistance that hinders the movement occurs, and the seizure is not completed immediately. Therefore, since the predetermined elapsed time is ensured in this way, the calming can be completed with certainty.
On the other hand, when the lowering movement of the bottom plate is completed in this way, it does not immediately shift to the rising movement, and the certainty of the settling on the paper accompanying the lowering movement is ensured between the completion time of the lowering movement and the start time of the rising movement. Since a so-called waiting time of a predetermined time length is set and secured in order to reduce the size, it is possible to further enhance the action of reducing the adhesion between the sheets even for large-sized sheets. It becomes. In other words, when large-size paper having a larger paper surface area than the paper size that is frequently used by the image forming apparatus is expected to be a normal paper size, it is naturally stacked in the paper feed tray. As the stored paper, the area of the paper surfaces in contact with each other is widened. However, if an air layer can be interposed in a part of the area of the paper surface in contact as described above, the air layer can be expanded to other regions. Even if it stays in the partial area, the position occupied by the partial area with respect to the entire area is moved, and the so-called part of the air layer is transferred to reduce the adhesion force. It can be expected to affect the entire area.

  Further, when the bottom plate is lowered, by supplying a high voltage from the power source to the motor as the drive unit, the descent speed for driving the bottom plate is increased, so the time required for the descent can be shortened. That is, when the bottom plate is driven downward, a high voltage is supplied from the power source to the motor, and the rotational driving force output from the motor is set to a higher rotational speed than when it is driven upward. Since it is faster than the ascending speed, the time during which the bottom plate is lowered from the upper limit position to the lower limit position can be shortened compared to when it is driven up. In particular, since the operation consisting of raising and lowering the bottom plate is not completed in one time and is continued a plurality of times, a total of a plurality of times shortened by the one operation is a plurality of times. The total time required to complete each operation is reduced, and a significant reduction is possible.

In addition, it is preferable to comprise so that the time after the bottom plate descends until it starts to rise can be arbitrarily set within several seconds to several tens of seconds. That is, the time for which the motor operation waits from the time when the bottom plate completes the descent and reaches the lower limit position to the time when the operation to raise the bottom plate at the lower limit position is started, that is, between the descent completion time and the rise start time. The motor operation stop time may be arbitrarily set by the user at a specific time within a time range from several seconds to several tens of seconds. Further, the change of the stop time by the user may be performed using an operation input unit provided in advance in the image forming apparatus, and a numerical value representing the time desired by the user is directly input. However, if the operation input unit has a display screen in advance, the current stop time that has been set may be adjusted within the above range.
Therefore, when the stop time can be arbitrarily set as described above, so-called variable, the stop time depends on the paper type and paper size that affect the degree of adhesion between the stacked sheets. Can be set appropriately. In other words, it is possible to set a longer stop time for a paper type such as coated paper with a high degree of adhesion, or a large size paper that takes more time to fall, so that the paper can be reliably settled. .

It is preferable that the number of times that the bottom plate is moved up and down is arbitrarily set to several to several tens of times so that a user or the like can set it. In other words, the change in the number of operations by the user may be performed using an operation input unit provided in advance in the image forming apparatus, and a numerical value representing the number of operations desired to be set by the user is directly input and operated. However, if the operation input unit has a display screen in advance, the current operation count that has been set may be adjusted within the above range.
Therefore, when the number of operations can be arbitrarily set in this way, so-called variable, the number of operations can be set appropriately according to the type of paper that affects the degree of adhesion between the stacked sheets. It is possible to facilitate the separation by further reducing the degree of adhesion. That is, it is possible to set a larger number of operations and move the sheet up and down more for paper type paper such as coated paper with high adhesion.

Next, a specific control example executed by the control unit will be described based on the flowchart shown in FIG.
That is, as shown in FIG. 3, when the power of the image forming apparatus is turned on, the control for facilitating the separation between the sheets is started. Further, the image forming apparatus starts preheating operation of a fixing unit (not shown), and performs this control in parallel between the time when the power is turned on and the time when the fixing unit is heated to a predetermined temperature and the preheating is completed. Is implemented. Note that the timer as the time counting means and the number counter as the counting means included in the control unit are each reset to zero value.

First, in S01, time counting by a timer is started.
Next, in S02, the timer performs a standby process to continue counting until the count value reaches a preset time value. If this count value is less than the predetermined time value, the counting is continued, whereas if it is equal to the predetermined time value, the counting process in S02 is terminated, and the process proceeds to S03. . In other words, the process of S03 is executed when the set time has elapsed from the start of the time count.

In S03, an operation process for moving the bottom plate up at a lower speed than the lowering operation is executed. That is, a driving current having a polarity and a low voltage in the forward direction is supplied from the power source to the motor, and the motor outputs the low-speed rotational driving force in the forward direction.
In S04, it is determined whether or not the bottom plate rising at a low speed has reached the upper limit position. If the bottom plate does not reach the upper limit position, the process returns to S03, and the bottom plate continues to rise. If the upper limit position has been reached, the process proceeds to S05. In S05, the motor output operation is immediately stopped, and the process proceeds to S06. Even when the output operation of the motor is stopped, the bottom plate does not naturally descend as described above, and maintains the posture in which one end is raised.

In S06, an operation process for lowering the bottom plate at a high speed is performed. That is, a reverse polarity and high voltage drive current is supplied from the power source to the motor, and a high speed rotational drive force in the reverse rotation direction is output from the motor. In this way, the ascending and descending operations of the bottom plate are successively performed in this order.
In S07, it is determined whether or not the bottom plate that descends at a high speed has reached the lower limit position. If the bottom plate does not reach the lower limit position, the process returns to S06, and the descent continues while the bottom plate reaches the lower limit position. If it has reached, the process proceeds to S08. In S08, the motor output operation is immediately stopped, and the process proceeds to S09.

In S09, the count value of the count counter is incremented by one.
In S10, it is determined whether or not the count value is a predetermined count value set in advance. If the count value is less than a predetermined count value smaller than the predetermined count value, the process returns to S01. On the other hand, the series of processes from S01 to S09 described above is repeated. On the other hand, if the count value is a predetermined number of times, the series of processes is not repeated and the process is terminated.
Before the termination process, the timer as the time counting means and the number counter as the counting means may reset the respective count values to zero values, or when starting this control, the above S01 to The two count values may be reset to zero values before the execution of the control body consisting of S10.

As described above, if the control program based on the above-described flowchart is added to the control program used in the existing sheet feeding tray device, the above-described effects can be obtained, and thus a wide application range can be obtained. That is, as an existing sheet feeding tray device, at least the sheet feeding tray described above and a bottom plate provided on the sheet feeding tray, a drive unit that drives the bottom plate in a predetermined manner, and a predetermined upper limit detection sensor and a lower limit detection sensor And a control unit that controls the drive output operation of the drive unit based on the detection result of the upper limit detection sensor and the detection result of the lower limit detection sensor, the control can be performed without changing the device configuration at all. The above-described embodiment can be realized only by changing the program.
On the other hand, in order to perform the above-mentioned operation, it is not necessary to provide a new dedicated mechanism consisting of additional members as component members and detection members, and without newly installing a dedicated fixed guide member, In this way, the structural member and the detection member that perform the normal paper feeding operation can be used as they are, and only the control program needs to be changed. Therefore, the cost can be extremely reduced and can be easily realized.

  In the above flowchart, the process of driving the bottom plate downward is performed by driving the bottom plate downward by the drive unit, and the lower limit detection sensor detects whether the bottom plate has reached the lower limit position by this downward driving, and stops the downward driving. However, the present invention is not limited to this, and using the timer function of the control unit, the time taken to drive up the bottom plate is measured, that is, timed, and this counted up drive The time is stored in the storage unit that the control unit has in advance, and the ascending driving time has elapsed since the descent driving was started without the detection by the lower limit detection sensor using the stored ascending driving time. At this point, a process of stopping the descending drive may be performed. That is, instead of stopping the descending drive based on the detection from the lower limit detection sensor, the ascending drive time is set from the time when the descending drive is started by setting the ascending drive time to a time for continuing the descending drive. When the time elapses, the lowering drive is stopped, and the apparatus configuration may be a configuration in which the lower limit detection sensor is omitted from the above configuration.

Specifically, the paper feed tray device is mounted with a paper feed tray for storing paper as transfer paper and a length approximately half of the length in the paper feed direction. A bottom plate having a trailing edge as a swing fulcrum with respect to the paper feed tray, a drive unit that swings and drives the bottom plate to move up and down, and when the bottom plate is raised, the top sheet of paper loaded on the bottom plate is fed. An upper limit detection sensor that detects that the position for paper conveyance has been reached, and a control unit that controls the drive unit in a predetermined manner, that is, controls the drive unit for an arbitrary time or amount, and its drive direction. The control unit continuously performs the operation of swinging the bottom plate by the driving unit when the paper feeding and conveyance is not designated, and raising and lowering approximately half of the sheets stacked on the bottom plate. Control is repeated multiple times.
The control unit has a storage unit that counts the time taken to drive the bottom plate up and down and stores the time, and the time taken to raise the bottom plate based on the detection of the upper limit detection sensor. Is stored in the storage unit, and the lower limit for lowering the bottom plate after ascending is the time stored in the storage unit.

More specifically, in the above flowchart, in addition to the above-described processing in S03, in S03, a timer for counting the time taken to drive the bottom plate upward starts counting time, and S05 In S05, in addition to the above-described processing in step S05, the timer count is stopped, and the counted up driving time is stored in the storage unit.
In addition to the above-described processing in S06, in S06, a timer for counting the time elapsed since the start of the descent driving of the bottom plate starts its time counting. Next, in addition to the above-described processing in S07, in S07, the elapsed time of the descent drive counted by the timer is compared with the ascending drive time, and the elapsed time of the former descent drive is compared with the latter descent drive. If the time value is shorter than the time, the process returns to S06 to continue the descent drive and continue the time count. On the other hand, if the time value becomes equal to the predetermined time value, the process proceeds to S08. To do. In the determination process of S07, when the descending drive speed is set higher than the ascending drive speed, the ascending drive time as a reference is shortened by the ratio of the descending drive speed to the ascending drive speed. The ascending drive time is used.
In S08, the descent drive is immediately stopped, the timer count is stopped, and the timer count value is reset to zero. The ascending drive time stored in the storage unit is also reset to zero, and when the count value is less than the predetermined number of times, the ascending drive time is newly set in S03 to S05 with the next ascending drive. get.

Therefore, according to the configuration in which the lower limit detection sensor is not required in this way, the existing sheet feed tray apparatus described above does not have the lower limit detection sensor but the existing sheet feed tray apparatus having only the upper limit detection sensor. Since this embodiment can be realized, a wider application range can be obtained.
On the other hand, it is possible to avoid malfunction of the control related to the bottom plate lowering drive based on the erroneous detection of the lower limit detection sensor, and to improve the reliability in the control related to the driving of the bottom plate.

  Note that the start timing of the drive control for performing the predetermined operation for reducing the adhesion force described above is performed when the predetermined number of sheets are set in the sheet feed tray and the sheet feed tray is inserted into the image forming apparatus. Although the startup preparation operation of the apparatus is started immediately after the power of the forming apparatus is turned on and the image forming apparatus enters the preheating mode, these timings are different from each other without being excluded from each other. Since it is a point in time, you may combine suitably.

According to the invention of claim 3, when the bottom plate is operated, the upper limit is set to the time required until the upper limit is reached by using the upper limit detection sensor of the paper feed unit, and the bottom plate is operated fully. In addition, the stacked transfer sheets can be bent as much as possible, and the adhesion can be reduced. That is, when the bottom plate is driven to swing, it is detected that the bottom plate has reached the upper limit position using the upper limit detection sensor and is controlled to stop based on the upper limit position detection, while the bottom plate has reached the lower limit position, Without using a sensor, the descent drive time is measured and the stop control is performed when the descent drive time reaches a predetermined time, that is, when the predetermined time has elapsed since the bottom plate was driven toward the lower limit position. The stop control is performed, and this predetermined time is the time taken for the bottom plate that is actually driven up to reach the upper limit position from the lower limit position.
On the other hand, since the lower limit position sensor for detecting that the bottom plate has reached the lower limit position is unnecessary, the cost can be reduced.

  According to the fourth aspect of the invention, by making sure that the bottom plate can be lowered to the lower limit, the transfer paper can be bent as much as possible, and the adhesion can be reduced.

  According to the invention of claim 5, by moving the bottom plate up and down immediately after setting the transfer paper, it is possible to bend the transfer paper before feeding and reduce the adhesion.

  According to the sixth aspect of the present invention, the vertical movement of the bottom plate can be completed immediately after the image forming apparatus is turned on during the start-up preparation operation of the apparatus. There is no problem even if a copy operation is requested.

  According to the seventh aspect of the invention, when the image forming apparatus enters the preheating mode, the adhesion can be reduced without applying a load to the power supply built in the apparatus.

  According to the eighth aspect of the present invention, when the bottom plate is lowered, the transfer paper does not fall immediately because it is in contact with the side fence or the entire reference wall that regulates the position of the transfer paper. By waiting for the bottom plate to rise until it completely falls, the adhesion of the transfer paper from the bottom paper to the top paper can be reliably reduced. Therefore, in the process in which the transfer paper settles when the bottom plate is lowered, the transfer paper has its peripheral edge in contact with the side fence and the front reference wall provided in the paper tray. A frictional resistance that hinders the movement of the roller occurs, and the settling is not completed immediately. Therefore, since the predetermined elapsed time is ensured in this way, the calming can be completed with certainty.

  According to the ninth and tenth aspects of the present invention, it is possible to shorten the time required for the descent by increasing the speed at which the bottom plate descends. That is, since the bottom plate lowering drive speed is set to be higher than the ascending drive speed, even if the swinging motion that descends after the bottom plate rises is repeated multiple times, these multiple swinging motions are repeated. Can greatly reduce the overall time required to complete the process.

  According to the invention of claim 11, since the image forming apparatus includes the paper feed tray device according to any one of claims 1 to 10, it is possible to improve the paper feed conveyance quality of the image forming apparatus.

  According to the twelfth aspect of the present invention, since the image forming apparatus according to the eleventh aspect is any one of a copying machine, a printer, a facsimile, or a combination machine combining some of these, these copying machines Also in each apparatus configuration such as the above, it is possible to improve the respective paper feed and conveyance qualities.

1 is a schematic front view illustrating an overall configuration of a paper feed tray apparatus according to an embodiment of the present invention. The operation of the paper feed tray device of this embodiment will be described, (a) shows a state in which sheets are stacked in a horizontal posture, (b) shows a state in which one half of the paper is in an upward inclined posture, (C) is a conceptual view and a partially enlarged view, respectively, showing a state in which an air layer is interposed between stacked sheets. 5 is a flowchart illustrating a specific control example used in the sheet feeding tray device of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper feed tray 2 Bottom plate 3 Drive part (electric motor) 4 Power supply 5 Control part 6 Upper limit detection sensor 7 Lower limit detection sensor 8 Lifting lever 10 Calling roller 11 Paper feed roller 12 Separation roller A Paper feed tray device S Paper (transfer paper)

Claims (12)

A predetermined number of transfer sheets placed in a substantially horizontal state are stacked and stored, and one half of the stacked transfer sheets in the feeding direction is inclined upward so that the leading edge of the uppermost transfer sheet reaches the paper feed position. In the paper feed tray device configured as described above,
The sheet feeding tray device is characterized in that at a predetermined timing other than the time of sheet feeding, the operation of returning to the horizontal state after tilting upward is continuously repeated a predetermined number of times. A paper feed tray for storing transfer paper, a bottom plate on which a length approximately half of the length in the feed direction of the transfer paper is placed and the rear end in the feed direction is a swinging fulcrum with respect to the paper feed tray, A drive unit that swings and drives the bottom plate to move up and down, and an upper limit for detecting that when the bottom plate is raised, the uppermost sheet of transfer paper loaded on the bottom plate has reached the position for feeding and conveying A paper feed tray device comprising a detection sensor and a control unit for controlling the drive unit to a predetermined level,
The control unit continuously performs the operation of causing the bottom plate to swing by the drive unit when the paper feed conveyance is not specified, and raising and lowering approximately half of the transfer paper loaded on the bottom plate. The sheet feeding tray device is controlled to be repeated a plurality of times. The control unit has a storage unit that counts the time taken to drive the bottom plate up and down and stores the time.
The time taken to raise the bottom plate is stored in the storage unit based on the detection by the upper limit detection sensor, and the lower limit for lowering the bottom plate after being raised is the time stored in the storage unit. Item 3. The paper feed tray device according to Item 2. A paper feed tray for storing transfer paper, a bottom plate on which a length approximately half of the length in the feed direction of the transfer paper is placed and the rear end in the feed direction is a swinging fulcrum with respect to the paper feed tray, A drive unit that swings and drives the bottom plate to move up and down, and an upper limit for detecting that when the bottom plate is raised, the uppermost sheet of transfer paper loaded on the bottom plate has reached the position for feeding and conveying A sheet feeding tray device comprising: a detection sensor; a lower limit detection sensor for detecting that the bottom plate is at a lower limit; and a control unit for controlling the drive unit to be predetermined.
The control unit continuously repeats the swinging motion of raising and lowering the bottom plate a plurality of times based on the detection of the upper limit detection sensor and the detection of the lower limit detection sensor when paper feed conveyance is not designated. A paper feed tray device characterized by   5. The sheet feeding tray apparatus according to claim 4, wherein the start timing of the control is when a sheet feeding tray loaded with transfer sheets is set in the apparatus main body.   The sheet feeding tray device according to claim 4, wherein the start timing of the control is when the power of the apparatus main body is turned on.   5. The sheet feeding tray apparatus according to claim 4, wherein the start timing of the control is when the apparatus main body enters a preheating mode.   8. The rocking motion is continuous without a gap when moving from ascending to descending, and is spaced a certain time when moving from descending to ascending. Paper tray device.   9. The paper feed tray device according to claim 2, wherein the swinging motion has a lowering speed than a rising speed.   The power source that supplies power to the drive unit is configured to be able to output one of two types of power sources: a power source voltage at the time of rising and a power source voltage at the time of falling. 10. The paper feed tray device according to claim 2, wherein the drive unit is driven with a high power supply voltage.   An image forming apparatus comprising the paper feed tray device according to claim 1.   The image forming apparatus according to claim 11, wherein the image forming apparatus is any one of a copying machine, a printer, and a facsimile machine, or a multifunction machine that combines some of them.

Images