JP2012091896A - Paper feeder and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lift up neighboring loading trays with small difference in level of ascending.SOLUTION: The neighboring loading trays 5a, 5b are displacement-controlled to upper paper feeding positions, according to consumption of loaded paper sheets 7a, 7b. Slide terminal parts 17a, 17b are projected from the loading trays 5a, 5b, and are slide-displaced according thereto. Position detection parts 15 detect the positions of loading trays according to abutment positions where slide terminal parts 17a, 17b slidably abut on opposed faces of insulating substrates 19a, 19b which are disposed within displacement ranges of the loading trays 5a, 5b, and thereby acquire position detection signals. Based on the position detection signals, a displacement control part 13 performs a stop control of uppermost loading trays 5a, 5b when the other loading trays 5a, 5b are separated from the uppermost loading trays 5a, 5b by not less than a predetermined distance, and performs a control of displacing the uppermost loading trays 5a, 5b again when the distances of the other loading trays 5a, 5b from the uppermost trays 5a, 5b are within the predetermined distance.

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device and an image forming apparatus, and more particularly to a paper feeding device suitable for being mounted in an image forming apparatus such as a printer, a copying machine, a facsimile machine, and a multifunction peripheral (MFP) having these functions. The present invention relates to an improvement of the image forming apparatus.

  In this type of image forming apparatus, a latent image is formed on the surface of a rotating photoconductor based on optically read image data, a toner image is formed from the latent image with toner, and is supplied from a built-in paper feeding device. A configuration is well known in which a toner image is transferred from a rotating photoconductor to a paper sheet, and the paper sheet is heated and fixed through a heat fixing unit.

  In order to enable a large amount of printing in the image forming apparatus, for example, a stacking tray on which about 1500 sheets of paper can be placed side by side, and when the paper on one stacking tray is consumed, the other stacking Controls switching of the paper feed rollers, etc., so that the paper on the tray is fed, and controls switching of the paper feed rollers, etc., so that when the paper on the other stacking tray is exhausted, the paper on the other stacking tray is fed again. A paper feeding device has been proposed.

  In such a configuration, if paper is alternately supplied to the stacking tray where the paper has been consumed, a large amount of continuous printing is possible. Therefore, in order to ensure smooth large-scale printing, the paper is detected based on the position detection of the stacking tray. It is important to know the remaining amount and replenish it.

  Conventionally, as shown in FIG. 6, this type of sheet feeding apparatus A is individually provided with lift portions 3 a and 3 b that move up and down by driving a lift motor (not shown) on the inner bottom of the unit case 1. The stacking trays 5a and 5b are placed on the stacking trays 5a and 5b, and the loading trays 5a and 5b are lifted and displaced by the lift portions 3a and 3b along with the consumption of the paper 7a and 7b set on the stacking trays 5a and 5b. There is known a configuration in which the position detection unit 9 detects the displacement position. In addition, the code | symbol 11 in a figure is a partition plate in the unit case 1 and partitioning between these stacking trays 5a and 5b.

  In the paper feeder A described above, when the partition plate 11 in FIG. 6 is removed, for example, A3 size larger than the individual stacking trays 5a and 5b on the adjacent stacking trays 5a and 5b for A4 size, for example. Sheet can be loaded, and the sheet can be fed more than the size that can be loaded on each of the stacking trays 5a and 5b.

  By the way, as a general conventional gazette for setting a large amount of paper in an image forming apparatus, for example, a paper feeding device of Japanese Patent Application Laid-Open No. 2001-261167 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-302018 (Patent Document 2). A paper remaining amount detection method has been proposed.

JP 2001-261167 A JP 2001-302018 A

  However, in the above-described paper feeder A, when the partition plate 11 is removed and large size sheets are stacked on the left and right adjacent stacking trays 5a and 5b, the independent adjacent stacking trays 5a and 5b are moved at the same ascending speed. Need to lift up.

  However, the loading trays 5a and 5b are lifted up by using individually arranged and connected lift motors as drive sources. However, the loading trays 5a and 5b are different in lift-up ascending speed due to the difference in torque between the left and right lift motors and the motor component variation. There is a concern that the sheets stacked on the stacking trays 5a and 5b may be inclined, and the inclination of the stacked sheets is likely to cause loss of alignment of the stacked sheets or poor feeding.

  Furthermore, excessive tilting can cause component damage due to mechanical interference.

  The present invention has been made to solve such a problem. In the configuration in which the paper can be lifted up individually by the individual loading trays and the adjacent loading trays can be lifted up integrally, the adjacent loading trays can be It is an object of the present invention to provide a sheet feeding device and an image forming apparatus that can easily lift them up with a small difference in rising level.

  In order to solve such a problem, a paper feeding device according to claim 1 of the present invention is a stacking tray in which sheets are stacked and controlled to be displaced to an upper sheet feeding position by consumption of the sheets, and are adjacent to each other. A plurality of stacking trays arranged side by side, a slide terminal portion projecting from each stacking tray and slidably displaced according to the stacking tray, and each loading tray is disposed within a displacement range of the slide terminal portions. It is an electrode pattern in which the slide terminal part facing it is slidably abutted on each opposing surface of the insulating substrate, and a predetermined potential is applied to detect the position of the stacked tray according to the abutment position of the slide terminal part A plurality of position detection units on which electrode patterns for obtaining position detection signals to be formed are formed, and on the basis of the position detection signals, the other stacking tray When it is determined that the distance is more than the predetermined interval, stop control of the displacement of the preceding stacking tray, and re-displacement control of the preceding stacking tray when the position of the other stacking tray falls within the predetermined interval. A displacement control unit.

  In the sheet feeding device according to claim 2 of the present invention, the position detection unit forms a plurality of electrode patterns on each facing surface of the insulating substrate, each of which has a different displacement range direction divided into a plurality of sections. In this configuration, a signal corresponding to a combination of a short circuit and an open circuit between the electrode patterns for each section by the slide terminal portion is obtained as a position detection signal.

  In the sheet feeding device according to claim 3 of the present invention, the position detection unit has a short-circuit pattern that is commonly formed in the remaining sections except for one section among the plurality of sections on each facing surface of the insulating substrate; The electrode pattern is different for each section, and a signal corresponding to a short-circuit combination of the short-circuit pattern and the electrode pattern for each section by the slide terminal portion is obtained as a position detection signal.

  The sheet feeding device according to a fourth aspect of the present invention is configured such that the position detection unit includes the removed one section as one end section of the plurality of sections.

  In the sheet feeding device according to claim 5 of the present invention, the position detection unit has a resistance pattern formed in the direction of the displacement range on each facing surface of the insulating substrate and a short-circuit pattern along the resistance pattern. In this configuration, a position detection signal is obtained from a circuit formed by a short circuit between the resistance pattern and the short circuit pattern by the slide terminal portion.

  An image forming apparatus according to a sixth aspect of the present invention forms image data on a paper fed from the paper feeding device according to any one of the first to fifth aspects and a paper fed from the paper feeding device having the paper feeding device. And an image forming unit.

  In such a sheet feeding device according to the first aspect of the present invention, based on the position detection signal from the position detection unit for each stacking tray, the other stacking trays are more than a predetermined distance from the stacking tray that precedes the top most. When it is determined that it is separated, the displacement of the preceding loading tray is controlled to stop, and when the position of the other loading tray falls within the predetermined interval, the preceding loading tray is controlled to be re-displaced. It is easy to lift them up to the paper feed position with a small rise level difference between adjacent stacking trays.

  In the sheet feeding device according to the second aspect of the present invention, a plurality of electrode patterns made different for each section are formed on each facing surface of the insulating substrate, and short-circuiting and opening between the electrode patterns for each section by the slide terminal portion. Since a signal corresponding to the combination is obtained as a position detection signal, it is possible to lift up adjacent stacking trays with a small rise level difference based on stepwise position detection with a simple configuration.

  In the sheet feeding device according to claim 3 of the present invention, the short-circuit pattern commonly formed in the remaining sections except for one section among the plurality of sections on each facing surface of the insulating substrate is made different from each other. Since the signal corresponding to the short-circuit combination of the short-circuit pattern and the electrode pattern for each section by the slide terminal portion is obtained as the position detection signal, it is possible to detect the position step by step with a simpler configuration. Based on this, it is possible to lift up adjacent loading trays with a small difference in rising level.

  In the sheet feeding device according to claim 4 of the present invention, since the one section removed in the position detection unit is a section at one end of the plurality of sections, the configuration for acquiring the position detection signal is further simplified. Is done.

  In the sheet feeding device according to claim 5 of the present invention, the position detection unit has a resistance pattern formed in the displacement range direction and a short-circuit pattern along the resistance pattern on each facing surface of the insulating substrate. Since the position detection signal is obtained from the circuit formed by the short circuit between the resistance pattern and the short circuit pattern by the slide terminal part, based on continuous position detection in a simple configuration, it is possible to accurately detect adjacent stacking trays with a small rise level difference. Lift up is possible.

1 is a schematic configuration diagram illustrating an embodiment of a paper feeding device according to the present invention. It is a principal part top view which shows the position detection part in FIG. It is a chart explaining operation | movement of the paper feeder which concerns on this invention. FIG. 2 is an internal configuration diagram illustrating an internal configuration of an image forming apparatus according to an embodiment of the invention equipped with a sheet feeding device according to the invention. It is a principal part top view explaining the other example of the paper feeder which concerns on this invention. It is a schematic block diagram which shows the conventional paper feeder.

  Embodiments of a paper feeding device and an image forming apparatus according to the present invention will be described below with reference to the drawings. In the sheet feeding device according to the present invention, the same reference numerals are given to the same parts as those in the conventional configuration.

  FIG. 1 is a schematic configuration diagram showing an embodiment of a paper feeding device A according to the present invention.

  In FIG. 1, a pair of lift portions 3a and 3b that move up and down by a motor drive, for example, are juxtaposed on the inner bottom of a unit case 1 having a box shape with an open top. Loading trays 5a and 5b on which 7a and 7b are set are placed and fixed on each. In FIG. 1, reference numeral 11 denotes a partition plate that is detachably installed on the inner bottom of the unit case 1 between the stacking trays 5 a and 5 b.

  The lift units 3a and 3b move the trays 5a and 5b upward by a lift motor (not shown) that is driven and controlled as the paper 7a and 7b set for the stacks 5a and 5b is fed. Has a function of moving them downward.

  The lift parts 3a and 3b are controlled to be lifted and displaced by a displacement control part 13 which will be described later.

  The stacking trays 5a and 5b are regulated so that the uppermost portions of the sheets 7a and 7b are always positioned at the sheet feeding position P which is the upper open position of the unit case 1, and consumption by feeding the sheets 7a and 7b is reduced. Along with the displacement.

  The following position detector 15 is formed for detecting this position in accordance with the upward displacement of the stacking trays 5a and 5b.

  The position detection unit 15 includes an insulating substrate 19a, 19b disposed in a displacement range of slide terminal portions 17a, 17b, which will be described later, and an electrode pattern, which will be described later, in which the slide terminal portions 17a, 17b facing the substrate are slidably contacted. And an electrode pattern (DIG0, DIG1, DIG2, GND) that outputs a position detection signal to detect a stacking tray position according to the contact position of the slide terminal portions 17a, 17b when a predetermined potential is applied. Is formed.

  The position detection unit 15 arranged for each of the stacking trays 5a and 5b has the same configuration, and details of the electrode pattern will be described later.

  The slide terminal portions 17a and 17b have a shape in which a conductive leaf spring is curved in a U shape, and the stacking tray 5a projects in a direction different from the adjacent stacking trays 5a and 5b, for example, in the opposite direction. 5b is cantilevered on the side, and the tip elastically contacts the opposing surface of the insulating substrates 19a and 19b, and slides on the insulating substrates 19a and 19b by the vertical displacement of the stacking trays 5a and 5b. It has become.

  The insulating substrates 19a and 19b are arranged on the side opposite to the partition plate 11 with the respective stacking trays 5a and 5b interposed therebetween, and the vertical displacement range of the adjacent stacking trays 5a and 5b, that is, the upper and lower sides of the slide terminal portions 17a and 17b. The electrode pattern DIG0, DIG1, DIG2, and GND as shown in FIG. 2 are formed on the opposing surface, respectively, having a length in the vertical (longitudinal) direction that is slightly longer than the direction displacement range. The position detector 15 described above is formed.

  Since the insulating substrates 19a and 19b and the electrode patterns DIG0 to GND formed thereon are the same, only one of them will be described below and the other will be omitted.

  The vertical direction of the insulating substrate 19a (19b) is divided into eight equal sections D1, D2, D3, D4, D5, D6, D7, and D8, and each section D1 to D8 extends in the vertical (longitudinal) direction. Electrode patterns DIG0, DIG1, DIG2, and GND are formed, and the presence and absence and width shapes of these electrode patterns DIG0 to GND in the individual sections D1 to D8 are different. The electrode patterns DIG0 to GND are formed by a known printing method or the like.

  The electrode patterns DIG0 to GND are external connection portions P0, P1, P2, and P3 at the lower end portion of the insulating substrate 19a (19b). From the left side of the insulating substrate 19a (19b) in the drawing, the electrode patterns DIG0 and DIG1 , GND, DIG2 are formed in the vertical direction with an interval in that order. Although not shown, a predetermined DC voltage (for example, +3 V, “1” potential) is applied to the electrode patterns DIG0 to DIG2 from the external connection portions P0 to P2. The ground (“0” potential) is connected to the external connection portion P3 of the electrode pattern GND.

  That is, the electrode pattern DIG0 is formed in an elongated unit band shape from the lower end portion of the insulating substrate 19a (19b) and extends upward in the section D1, and extends upward in a double width over the sections D2 to D5 to open the tip.

  The electrode pattern DIG1 formed on the right side of the electrode pattern DIG0 has a unit band shape in the sections D4 and D5, and has a double width in the sections D6 to D8, and extends on the extension line of the electrode pattern DIG0 (upper section of the insulating substrate 19a (19b)). D8), and the right end portion extends in a unit band shape to the lower end portion so as to surround the electrode patterns GND and DIG2.

  On the right side of the electrode pattern DIG1, an electrode pattern GND formed in a unit band shape extends upward from the lower end of the insulating substrate 19a (19b) to the section D1 to the section D7 in an elongated unit band shape.

  On the right side of the electrode pattern GND, the electrode pattern DIG2 extends upward from the lower end of the insulating substrate 19a (19b) in a double width from the section D1 to the section D2, and extends upward in the unit band shape to the sections D3 and D4. From D5 to D6, it is opened again with a double width.

  The electrode pattern GND is formed in common in the remaining sections excluding the upper one section D8 among the plurality of sections D1 to D8, and functions as a short-circuit pattern for short-circuiting the electrode patterns DIG0 to DIG2 as described later.

  The slide terminal portion 17a (17b) slides the electrode pattern (short-circuit pattern) GND in the process of sliding vertically on the insulating substrate 19a (19b) while being in electrical contact with the electrode patterns DIG0 to DIG2 and GND. The electrode pattern DIG0 to DIG2 has a function of shorting the double-width portion and the electrode pattern GND, and setting the external connection portions P0 to P2 of the shorted electrode patterns DIG0 to DIG2 to “0” potential. Yes.

  The external connection portions P0 to P2 of the electrode patterns DIG0 to DIG2 that are not short-circuited to the electrode pattern GND remain at “1” potential.

  When the slide terminal portion 17a (17b) is slid in the vertical direction on the insulating substrate 19a (19b), the form in which the electrode patterns DIG0 to DIG2 are short-circuited with the electrode pattern GND is changed in the sections D1 to D7. The external connection portions P0 to P2 of the patterns DIG0 to DIG2 change to “0” potential.

  FIG. 3 is a diagram illustrating a combination state of the potentials “1” and “0” of the electrode patterns DIG0 to DIG2 in the sections D1 to D8 in the position detection unit 15, and the sections D1 to D8 according to these combination states. Is specified, and a position detection signal is output from a processing circuit (not shown).

  For example, in the section D8 from 0% to 12.5%, the electrode patterns DIG0 to DIG2 are “1, 1, 1”, and in the section D7 from 12.5% to 25%, the electrode patterns DIG0 to DIG2 are “1, In the section D1 from 87.5% to 100%, the electrode patterns DIG0 to DIG2 become “1, 1, 0”, and the combination of the “1” potential and the “0” potential of the electrode patterns DIG0 to DIG2 Thus, the position of the slide terminal portion 17a (loading tray 5a) is specified, and this can be used for detecting the positions of the loading trays 5a and 5b.

  Returning to FIG. 1, the displacement control unit 13 is based on the position detection signal from the position detection unit 15 in a mode (unified mode) in which all the stacking trays 5 a and 5 b are displacement-controlled at the same speed. When it is determined that the other stacking trays 5a and 5b are separated by one section or more from the stacking trays 5a and 5b that are preceded most upward, the displacement of the preceding stacking trays 5a and 5b is stopped and controlled. When the other stacking trays 5a and 5b are within the same section, the preceding stacking trays 5a and 5b are controlled to be re-displaced.

  A specific method for stopping and controlling the displacement of the stacking trays 5a and 5b is performed by stopping the driving of the lift motor including the lift portions 3a and 3b or by disconnecting the drive connection from the lift motor to the stacking trays 5a and 5b. .

  In a mode (independent mode) in which all the stacking trays 5a and 5b are independently controlled to be displaced (independent mode), the displacement control unit 13 controls the displacement of each of the stacking trays 5a and 5b at an individual speed according to the sheet feeding status. In addition, it has a function of detecting the position.

  Next, the operation of the sheet feeding apparatus A according to the present invention will be briefly described.

  It is to be noted that the partition plate 11 between the A4 plate loading trays 5a and 5b is removed, A3 size paper 7c is loaded on both the loading trays 5a and 5b, and all the loading trays 5a and 5b are controlled to be displaced at the same speed. A description will be given assuming that the mode is selected.

  When 100% of the sheets 7c are set on the stacking trays 5a and 5b, the stacking trays 5a and 5b are positioned at the bottom and the slide terminal portion 17a contacts the lower part of the section D1 on the insulating substrates 19a and 19b, and only the electrode pattern DIG2 is provided. Is short-circuited to the electrode pattern (short-circuit pattern) GND, and the electrode patterns DIG0 to DIG2 become “1, 1, 0”.

  Therefore, it is possible to obtain a position detection signal indicating 100% by the processing circuit for the stacking trays 5a and 5b.

  When the paper 7c is consumed, the stacking trays 5a and 5b are raised according to the consumption amount, and the slide terminal portion 17a slides in a state where the insulating substrates 19a and 19b are in contact with each other. The electrode patterns DIG0 to DIG2 are short-circuited to the electrode pattern (short circuit pattern) GND, and the electrode patterns DIG0 to DIG2 become “0, 0, 0”. Therefore, it is possible to obtain a position detection signal indicating 50% for the stacking trays 5a and 5b.

  Further, when the sheet 7c is consumed and the stacking trays 5a and 5b are moved up to the uppermost portion and the slide terminal portion 17a reaches the section D8, the electrode patterns DIG0 to DIG2 are not short-circuited with the electrode pattern (short-circuit pattern) GND. Thus, the electrode patterns DIG0 to DIG2 become “1, 1, 1”.

  When a position detection signal indicating 0% is obtained for the stacking trays 5a and 5b, the stacking trays 5a and 5b are reset to a position of 100% by appropriate means, and the sheet 7c is loaded on the stacking trays 5a and 5b. If replenished, it is possible to prepare for the next paper feed.

  In the unified mode, the displacement control unit 13 constantly monitors the position detection signal while the stacking trays 5a and 5b are raised together. For some reason, the stacking trays 5a and 5b are most advanced, for example. When it is determined that the other stacking tray 5b is delayed by one section or more with respect to the stacking tray 5a, the displacement control unit 13 stops the displacement of the preceding stacking tray 5a, and the position of the other stacking tray 5b is compared with this. Enters the same section as the preceding loading tray 5a, the preceding loading tray 5a is re-displaced. The other stacked trays 5b that have been delayed are controlled to move upward as they are.

  Regarding the operation in the independent mode, the displacement stop control of the preceding loading trays 5a and 5b in the unified mode and the previous loading trays 5a and 5b are re-displaced when the positions of the other loading trays 5a and 5b enter the same section. Since it is the same except for a point, description is abbreviate | omitted.

  Next, an embodiment of an image forming apparatus B equipped with the above-described paper feeding apparatus A will be described with reference to FIG.

  In FIG. 4, the image forming apparatus B has an image capturing unit 23, a storage unit 25, an operation panel unit 27, a communication unit 29, and a printing unit 31 with the main control unit 21 as the center, and constitutes, for example, a multifunction peripheral. ing. The image forming apparatus B has a configuration other than this, but since it is not the gist of the present invention, description and illustration are omitted.

  For example, as shown in FIG. 4, the image reading unit 23 is arranged on the upper part of the main body case 33 of the image forming apparatus B, and optically reads an image from a printed document, for example, under the control of the main control unit 21. This is an image data input unit such as a known scanner that generates an electronic print job by performing filter processing or the like, and the generated print job is sequentially stored in the storage unit 25.

  The storage unit 25 is a readable / writable hard disk that stores read image data from the image reading unit 29 or received image data from the communication unit 29 and an operation program of the main control unit 21 under the control of the main control unit 21. .

  The operation panel unit 27 is arranged on the upper part of the main body case 33, and is controlled by the main control unit 21, for example, a known liquid crystal display panel as a display unit capable of displaying various operation states, and the operation of the apparatus. By pressing a key on which an image is displayed, it has a function as an input unit that accepts image reading, printing instructions, switching instructions between the unified mode and independent mode described above, and other instructions.

  The communication unit 29 in FIG. 4 is an interface unit that transmits and receives image data to and from an information processing apparatus (computer) via a network (not shown) according to a predetermined protocol under the control of the main control unit 21. is there.

  The printing unit 31 develops and creates print image image data from the image data, forms a toner image based on the image data, transfers and fixes the toner image onto a sheet, prints it, and discharges it.

  That is, the printing unit 31 uses the above-described paper feeding device A having the paper feeding device A disposed in the main body case 33, and develops the toner on the photosensitive drum with toner based on the print image image data, and transfers this onto the paper. The image forming unit includes a transfer unit 35 serving as an image forming unit, a fixing unit 37 that fixes a sheet onto which the toner image has been transferred, and the like. Reference numeral 39 denotes a paper discharge tray.

  The main control unit 21 includes a CPU, a ROM that stores an operation program for the CPU, and a working RAM (none of which are shown). The main control unit 21 is configured as described above, and includes the image reading unit 29, the storage unit 25, and the user. It has a function of controlling the history creating unit 7, the operation panel unit 27, the printing unit 31, the communication unit 29, the displacement control unit 13, and the like.

  The main control unit 21 has a function of switching and controlling the operation of the displacement control unit 13 based on the mode switching instruction from the operation panel unit 27 described above.

  As described above, the sheet feeding device A according to the present invention is the stacking trays 5a and 5b on which the sheets 7a and 7b are placed and controlled to be displaced to the upper sheet feeding position by consumption of the sheets 7a and 7b. The plurality of stacking trays 5a and 5b juxtaposed in this manner, and the slides that project from the individual stacking trays 5a and 5b in different directions and slide in accordance with the stacking trays 5a and 5b. With respect to the terminal portions 17a, 17b and the respective loading trays 5a, 5b, the sliding terminal portions 17a facing the respective opposing surfaces of the insulating substrates 19a, 19b arranged in the displacement range of the ride terminal portions 17a, 17b. , 17b are slidably contacted electrode patterns DIG0 to GND, and a predetermined potential is applied to correspond to the contact positions of the slide terminal portions 17a, 17b. Based on the position detection signal in the position detection unit 15 in which the electrode patterns DIG0 to GND for obtaining the position detection signal for detecting the stacking tray position and the mode in which the displacement of all the stacking trays 5a and 5b is controlled at the same speed, When it is determined that the other stacking trays 5a and 5b are more than a predetermined distance apart from the stack trays 5a and 5b that precede the top most of the stacking trays 5a and 5b, the displacement of the preceding stacking trays 5a and 5b is stopped and controlled. On the other hand, a displacement control unit 13 is provided for re-displacement control of the preceding stacking trays 5a and 5b when the positions of the other stacking trays 5a and 5b fall within a predetermined interval.

  In addition, the position detection unit 15 forms a plurality of electrode patterns DIG0 to GND in which the displacement range direction is divided into a plurality of sections divided on the opposing surfaces of the insulating substrates 19a and 19b. It has electrode patterns (short circuit patterns) GND that are formed in common in the remaining sections except for one section at one end, and electrode patterns DIG0 to DIG2 that are made different for each of the sections, and slide terminal portions 17a and 17b. Are formed so as to obtain a signal corresponding to the short-circuit combination of the electrode pattern (short-circuit pattern) GND and the electrode patterns DIG0 to DIG2 for each section as the position detection signal.

  Therefore, it is possible to perform height correction between the adjacent stacking trays 5a and 5b in a configuration in which the individual stacking trays can be lifted up individually and the adjacent stacking trays 5a and 5b can be lifted up integrally. It is possible to lift them up to the paper feeding position in a state where the difference in the rising level is small between the adjacent adjacent stacking trays 5a and 5b, and the paper 7c loaded on the adjacent stacking trays 5a and 5b is inclined so much. It is easy to lift up.

  Further, it is possible to detect the positions of the sheets 7a and 7b only by elastically contacting the slide terminal portions 17a and 17b provided on the stacking trays 5a and 5b with the insulating substrates 19a and 19b. By simply forming the electrode patterns DIG0 to GND on the corresponding insulating substrates 19a and 19b and bringing the slide terminal portions 17a and 17b into contact with each other from the opposite surface, according to the combination of shorting and opening between the electrode patterns for each section by the slide terminal portion Therefore, it is possible to lift up adjacent loading trays with a small difference in elevation level based on stepwise position detection.

  In particular, if the position detection unit 15 increases the number of sections and detects the positions of the stacking trays 5a and 5b in a stepwise manner, the sheet 7c loaded on the adjacent stacking trays 5a and 5b can be lifted up with little inclination. Is possible.

  By the way, the position detection unit 15 of the sheet feeding device A of the present invention has a configuration in which the electrode pattern (short-circuit pattern) GND is excluded only in the upper end section D8, but a configuration in which the electrode pattern (short-circuit pattern) GND is excluded in any section is also possible. In the configuration in which the removed one section is one end section, the electrode pattern (short-circuit pattern) GND can be formed short, and the shape can be easily reduced in size.

  Further, the position detection unit 15 of the sheet feeding apparatus A according to the present invention forms a plurality of electrode patterns DIG0 to GND having different displacement range directions in each section, and each section by the slide terminal portions 17a and 17b. If the signal corresponding to the combination of the short circuit and the open circuit between the electrode patterns DIG0 to GND is obtained as the position detection signal, the position of the adjacent stacking trays 5a and 5b can be easily detected with a simple configuration.

  The point is that the slide terminal portions 17a, 17b facing each other slide on the opposing surfaces of the insulating substrates 19a, 19b arranged in the displacement range of the slide terminal portions 17a, 17b between the facing trays 5a, 5b. Electrode patterns DIG0 to GND that are freely contacted, and a predetermined potential is applied to obtain position detection signals for detecting the stacking tray position according to the contact positions of the slide terminal portions 17a and 17b. It is sufficient if the position detection unit 15 is formed.

  Furthermore, the displacement control unit 13 in the sheet feeding device A of the present invention is not limited to the configuration in which the displacement of the preceding stacking tray 5a is stopped when the stacking trays 5a and 5b are separated by one section or more as described above. In the case of a configuration having a large number of sections, when it is determined that the distance is longer than a predetermined interval, the displacement of the preceding stacking tray 5a is stopped and the position of the other stacking tray 5b falls within the predetermined interval. In this case, the object of the present invention can be achieved even if the preceding loading tray 5a is controlled to be re-displaced.

  Furthermore, in the configuration of the sheet feeding device A of the present invention described above, the correspondence when the stacking trays 5a and 5b are separated by one section or more has been described, but the present invention is not limited to this.

  For example, even if a predetermined time has elapsed since the section of the preceding stacking tray 5a is switched, if the section switching of the other stacking tray 5b is not detected, the preceding stacking tray 5a is stopped until it is detected, It is also possible to configure such that the loading tray 5a that previously detected the section change is stopped each time, and the stop is released at the same time as the subsequent loading tray 5b is detected.

  In short, when it is determined that the other stacking tray 5b is separated by a predetermined distance or more from the stacking tray 5a that precedes the top most, the displacement of the preceding stacking tray 5a is stopped and controlled. The above-described displacement control unit 13 may be formed so that the preceding stacking tray 5a is re-displaced when the position 5b falls within a predetermined interval.

  In the sheet feeder A of the present invention described above, the slide displacement range of the stacking trays 5a and 5b is divided into a plurality of sections D1 to D8, and the position is detected stepwise (digitally) in each of the sections D1 to D8. Although the position detection unit 15 is formed as described above, the present invention is not limited to this.

  For example, as shown in FIG. 5, on the opposing surfaces of the insulating substrates 19a and 19b described above, an elongated strip-like high-resistance electrode pattern (resistance pattern) DIG3 and an electrode pattern formed in parallel with a slight gap therebetween (Short-circuit pattern) GND, and position detection signals are continuously transmitted from the external connection portion P4 formed by short-circuiting the electrode pattern (resistance pattern) DIG3 and the electrode pattern (short-circuit pattern) GND by the slide terminal portions 17a and 17b. Since the detection is performed in an analog manner, the adjacent stacking trays 5a and 5b can be lifted up based on continuous position detection with a simple configuration.

  In such a configuration, when the slide terminal portions 17a and 17b slide and displace due to the slide displacement of the loading trays 5a and 5b, the position of the resistance pattern DIG3 that is short-circuited by the electrode pattern (short-circuit pattern) GND changes, and the electrode pattern ( Since the resistance pattern) DIG3 changes the circuit resistance of the electrode pattern (short circuit pattern) GND, the adjacent trays 5a and 5b can be accurately lifted with a slight or consistent rise level difference based on continuous position detection. Is possible.

  In addition, the sheet feeding apparatus A according to the present invention is not limited to the configuration having the two stacking trays 5a and 5b, but can be implemented in a configuration in which a plurality of stacking trays 5a and 5b are adjacent to each other.

  Furthermore, in each of the electrode patterns DIG0 to DIG2 described above, some of the sections D2 to D5 are twice as wide as the other sections, but the present invention is not limited to double width. However, it is preferable to form partly wide from the viewpoint of ensuring reliable contact.

  Furthermore, the stacking trays 5a and 5b are not limited to the configuration in which the vertical displacement is controlled by the lift portions 3a and 3b that are moved up and down by the motor drive, and may be configured to be biased and displaced upward. The object of the present invention can be achieved as long as the stacked tray is displaced upward by the consumption of the paper.

  The image forming apparatus B equipped with the paper feeding device of the present invention has the same effect as the paper feeding device.

1 Unit case 3a, 3b Lift part 5a, 5b Stack tray 7a, 7b, 7c Paper 9, 15 Position detection part 11 Partition plate 13 Displacement control part 17a, 17b Slide terminal part 19a, 19b Insulating substrate 21 Main control part 23 Image capture Insertion section 25 Storage section 27 Operation panel section 29 Communication section 31 Printing section 33 Main body case 35 Transfer section 37 Fixing section 39 Paper discharge tray A Paper feeding apparatus B Image forming apparatuses DIG0, DIG1, DIG2 Electrode pattern DIG3 Electrode pattern (resistance pattern)
GND electrode pattern (short circuit pattern)
P0, P1, P2, P3, P4 External connections

Claims (6)

A plurality of stacking trays which are stacked and are controlled to be displaced to an upper sheet feeding position by consumption of the sheets,
A slide terminal portion protruding from each of the stacking trays and slidingly displaced according to the stacking tray;
For each of the stacking trays, an electrode pattern in which the slide terminal portion facing the insulating substrate disposed in the displacement range of the slide terminal portion is in contact with the slide terminal portion so as to be slidable, A plurality of position detection units on which the electrode pattern is formed to obtain a position detection signal for detecting the stacking tray position according to a contact position of the slide terminal unit to which a predetermined potential is applied
Based on the position detection signal, when it is determined that the other stacking tray is separated by a predetermined distance or more from the stacking tray that precedes the top most, the displacement of the preceding stacking tray is stopped and controlled. A displacement control unit for re-displacement control of the preceding loading tray when the position of the other loading tray falls within a predetermined interval;
A sheet feeding device comprising:   The position detection unit forms a plurality of the electrode patterns different for each section obtained by dividing the displacement range direction into a plurality of sections on each facing surface of the insulating substrate, and the slide terminal unit for each section The sheet feeding device according to claim 1, wherein a signal corresponding to a combination of a short circuit and an open pattern between electrode patterns is obtained as the position detection signal.   The position detection unit includes, on each facing surface of the insulating substrate, a short circuit pattern that is commonly formed in the remaining sections except for one section among the plurality of sections, and the electrode patterns that are different for each section. The sheet feeding device according to claim 2, wherein a signal corresponding to a short-circuit combination of the short-circuit pattern and the electrode pattern for each section by the slide terminal portion is obtained as the position detection signal.   The sheet feeding device according to claim 3, wherein the position detecting unit is configured such that the removed one section is a section at one end of the plurality of sections.   The position detection unit has a resistance pattern formed in the direction of the displacement range and a short circuit pattern along the resistance pattern on each facing surface of the insulating substrate, and the resistance pattern by the slide terminal unit and the short circuit pattern The sheet feeding device according to claim 1, wherein the position detection signal is obtained from a circuit formed by a short circuit.   A sheet feeding device according to any one of claims 1 to 5, and an image forming unit that forms image data on the sheet fed from the sheet feeding device having the sheet feeding device. Image forming apparatus.

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