JP4575840B2 - Paper feeder - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention is used in a paper feeding device that feeds paper that has been cut to a predetermined size to an image forming apparatus such as a printer or a copying machine, and even when the stacking tray is pulled out from the paper feeding device. The present invention relates to a paper feeding device capable of driving a stacking tray.

  The prior art will be described with reference to FIG. Intermediate position detection for detecting that the upper surface of the stacking tray 3 or the upper surface of the sheets 1 stacked on the stacking tray 3 is at the set position in the large capacity paper feeding device 2 capable of accommodating thousands of sheets 1 When the sheets are stacked, the cover 11 of the stacking tray 3 is opened, and the stacking tray 3 is lowered until the intermediate position detection sensor 7 detects the stacking of the sheets 1 (FIG. 3A). (B)). Further, when the sheets 1 are stacked, a lowering switch (not shown) is pressed, and the stacking tray 3 is lowered until it is detected again by the intermediate position detection sensor 7 (FIGS. 3C and 3D).

JP-A-11-11691

  When loading paper into the stacking tray, the stacking tray must be lowered to an intermediate position where it is easy to load paper. Further, when stacking sheets, it is troublesome to press down the lowering switch and lower the stacking tray to the intermediate position again. Also, it is not possible to detect a stacking abnormality when an amount of sheets exceeding the stacking tolerance of the sheet feeding device is loaded when loading sheets. In addition, when a worker runs a stack of paper, the control program of the paper feeder runs out of control and the stacking tray rises, and there is a risk that the clothes sleeve of the worker will be caught in the gap between the stacking tray, There is a risk of damaging the paper feeder itself.

  The present invention includes an upper surface detection sensor for detecting the upper surface position of the paper stacked on the stacking tray and a driving means such as a stepping motor for driving the stacking tray up and down, and when there is no paper on the stacking tray, When sheets are stacked on the upper surface and the stacking tray, when the upper surface detection sensor detects the upper surface of the stacked sheets, the stacking tray is lowered by a certain amount by driving the loading tray driving means by a certain amount. Control means is provided.

  In addition, a lower limit detection sensor for detecting that the stacking tray has been lowered to the lower limit position is provided, and when the lower limit detection sensor detects, a control means for stopping the lowering drive of the stacking tray is provided, and the upper surface detection sensor and the lower limit detection sensor are provided. When both sensors detect, it is judged that the stacking allowable amount of the sheet feeding device has been exceeded, and a control means for making a stacking abnormality is provided.

  Furthermore, an open detection sensor for detecting that the stacking tray has been pulled out from the paper feeding device is provided. When the open detection sensor detects that the paper feeding device has been pulled out, the hardware circuit detects the loading tray drive means. A circuit is provided in which the drive signal is turned off, and only the rise of the stacking tray cannot be driven.

According to the present invention, automatically for a certain amount stacking tray is lowered, can be loaded paper Runode smoothly be loaded immediately paper pull the stacking tray from the paper feed device.

  Further, if the stacking capacity of the sheet feeding device is exceeded, a stacking abnormality can be confirmed at an early stage when the sheet is loaded.

  Furthermore, even when the software control program runs away during work such as paper loading, the stacking tray of the paper feeding device does not rise, so that the safety of the operator can be maintained and damage to the paper feeding device can be prevented.

  The objectives of loading paper smoothly, checking paper stacking abnormalities at an early stage, and preventing the stacking tray from rising when the software runs out of control are realized by adding a simple hardware circuit and changing the software.

  An embodiment of the present invention will be described with reference to FIGS.

  First, a large-capacity paper feeding device 2 for supplying printing paper to the image forming apparatus will be described with reference to FIG. The sheets 1 are stacked on the stacking tray 3. The stacking tray 3 is configured to be raised and lowered by driving means (not shown). In the present invention, as an embodiment, the driving means is a stepping motor 10. Above the sheets 1 stacked on the stacking tray 3, a feeding unit for sequentially feeding the uppermost sheet 1 (not shown) is arranged. An open detection sensor 6 is installed at a position where it can be detected that the stacking tray 3 is pulled out when the stacking tray 3 is pulled out from the paper feeding device 2 to load paper. And a light interrupter that is provided between the light emitting units with a gap interposed therebetween. The upper surface detection sensor 4 installed on the upper portion of the stacking tray 3 is a reflection type photosensor. The lower limit detection sensor 5 installed at a position that can be detected when the stacking tray 3 reaches the lower limit position is a photointerrupter with an actuator that includes a light emitting portion and a light receiving portion provided through a gap between the light emitting portions. It is.

  A series of operations of the present invention will be described with reference to FIGS.

  FIG. 2 is a front view of a series of sheet loading operations showing an embodiment of the present invention. FIG. 3 is a timing chart of a series of operations for loading paper of FIG. When the sheet feeding operation for feeding printing sheets one by one to the image forming apparatus is not performed, the height at which the top surface of the stacking tray 3 or the top surface of the sheets stacked on the stacking tray 3 can be easily loaded at all times (hereinafter referred to as the following) 2), the stepping motor 10 of the driving means for the stacking tray 3 is driven in the downward direction from the position detected by the upper surface detection sensor 4 to lower the stacking tray 3 (FIG. 2). 3, (a)). Here, when the stacking tray 3 is pulled out from the sheet feeding device 2 and the sheet 1 is loaded on the stacking tray 3 (FIG. 2, 3 (b)), the sheet 1 loaded on the upper surface detection sensor 4 is detected. Then, the stacking tray 3 is automatically lowered by a certain number of steps ((c) in FIGS. 2 and 3). Further, when the sheets 1 are stacked, the stacking tray 3 performs a lowering operation ((d) in FIGS. 2 and 3). When the stacking tray 3 is lowered until the lower limit detection sensor 5 detects it, the lowering operation of the stacking tray 3 is stopped ((e) in FIGS. 2 and 3). Further, when the sheet 1 is loaded and the upper surface detection sensor 4 detects the loaded sheet 1, it is determined that the stacking capacity of the sheet feeding device 2 has been exceeded, and an error indicating a stacking abnormality is reported (FIGS. 2, 3). (F)).

  Next, a protection circuit when the control program of the sheet feeding device 2 according to the present invention runs away will be described with reference to FIG. In FIG. 4, the control unit 8 takes in signals from the upper surface detection sensor 4, the lower limit detection sensor 5, and the open detection sensor 6 and controls the stepping motor 10. When the loading tray 3 is pulled out from the paper feeding device 2 and the paper is being loaded, the control program of the paper feeding device 2 runs out of control and the loading tray 3 rises, and the clothes sleeves of the worker are loaded. When the open detection sensor 6 detects that the paper feeding device 2 has been pulled out so as not to get caught in the gap between the trays 3, it is a driving means for the stacking tray 3 by the hardware circuit 9 of the control unit 8. Circuit means for turning off the drive signal of the stepping motor 10 and making it impossible to drive only the rise of the stacking tray 3 is provided.

1 is a side view of a paper feeding device showing an embodiment of the present invention. FIG. 5 is a diagram illustrating a series of operation of loading a sheet as viewed from the front showing an embodiment of the present invention. 4 is a timing chart of a series of paper loading showing an embodiment of the present invention. The figure which shows the control structure of this invention. FIG. 6 is a schematic side view of a conventional paper feeding device.

Explanation of symbols

1 is paper, 2 is a paper feeder, 3 is a stacking tray, 4 is an upper surface detection sensor, 5 is a lower limit detection sensor, 6 is an open detection sensor, 7 is an intermediate position detection sensor, 8 is a control unit, and 9 is a hardware circuit. Reference numeral 10 denotes a stepping motor, and 11 denotes a cover.

Claims (1)

A stacking tray for stacking print sheets, a driving means for moving the stacking tray up and down, and an upper surface of the sheet stacked on the stacking tray or the upper surface of the stacking tray can be detected even when the stacking tray is pulled out from the sheet feeding device. In a paper feeding device that includes an upper surface detection sensor and a control unit that controls the driving unit, and is stored in the image forming apparatus or connected to the image forming apparatus to supply printing paper to the image forming apparatus.
When the open detection sensor detects that the stacking tray is pulled out from the sheet feeding device, the control unit performs control not to perform only the raising drive of the stacking tray .

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