JP2007169064A - Paper feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably detect an upper surface position of paper. <P>SOLUTION: This paper feeder is composed of an air jetting means for floating and separating an upper part of the paper loaded on a tray and a carrier belt sucking and carrying the paper of the uppermost position on the tray, and contacts an elastic shielding member with a light receiving surface of an optical analog sensor, by arranging the elastic shielding member on a shielding plate movable together with an upper surface of the paper and detecting the upper surface position, for always keeping the upper surface position of the uppermost position paper in a specific position by using the optical analog sensor for detecting the upper surface of the uppermost position paper. The elastic shielding member is arranged in parallel to the movable direction of the shielding plate, and is arranged so that a surface of contacting the elastic shielding member with the light receiving surface of the optical analog sensor, becomes the same plane as a surface of contacting the elastic shielding member with the shielding plate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a paper feeding device for a printer.

  Conventionally, a method for detecting the upper surface position of the uppermost sheet is a method for turning on / off an optical digital sensor in which a shielding plate in contact with the upper surface of the uppermost sheet is installed at a predetermined position, or a voltage change of the optical analog sensor. The upper surface position of the uppermost sheet is kept constant by the detection voltage (see, for example, Patent Documents 1 and 2). Further, an elastic member is used as a shielding plate for the optical analog sensor (see, for example, Patent Document 3).

  For the paper feeding device that separates the top of the paper by air blowing, sucks the paper by the suction conveyance belt, and sends it out, it is indispensable to always keep the top surface of the topmost paper constant. It is.

  Therefore, detection of the upper surface position of the uppermost sheet is made so that a shielding plate having a weight of a certain load or more is brought into contact with the upper surface of the sheet so as not to be affected by floating or flapping of the sheet by air for separation. The tray is raised and the upper surface position of the paper is kept constant by detecting whether or not the optical sensor installed at a predetermined position is detected. In general, digital sensors that detect ON / OFF are often used as optical sensors, but it is more stable to use analog sensors so that variations in height due to the effects of paper curl can be corrected. It is effective for detecting the upper surface position. In the case of an optical analog sensor, the light receiving side detects the change in the amount of light blocked by the light shielding side by changing the voltage to the light receiving side. There is a case.

  For this reason, there is known a paper feeding device in which an elastic shielding member is disposed and the elastic shielding member is made larger than the shielding plate and is brought into contact with the detection surface of the analog sensor so as to accurately detect the upper surface position of the paper. It has been. This configuration will be described with reference to FIGS.

  3 and 4, the upper portion of the paper 2 stacked on the tray 1 in the paper hopper (not shown) is separated at the leading edge by the air blowing mechanism 4, and only the uppermost paper 3 is sucked by the suction conveyance mechanism 5. And sent out. In order to accurately feed the sheets 2 one by one by the suction transport mechanism 5, it is necessary to always stably blow the air blown from the air blowing mechanism 4 to the number of sheets in order to separate the sheets 2. Therefore, in order not to be affected by the floating of the sheet due to the blown air, the shielding plate 6 that can hold the sheet with a certain weight or more is brought into contact with the upper surface of the rear end of the uppermost sheet 3 and the shielding plate 6 Is detected by the optical analog sensor 7, and the upper surface position of the paper 2 is kept constant by a mechanism (not shown) that moves the tray 1 up and down by detecting the upper surface position of the paper 2. In the optical analog sensor 7, the light emitting unit 8 and the light receiving unit 9 are arranged to face each other. In general, the light emitting unit 8 includes an LED lamp, and the light receiving unit 9 includes a CCD sensor. The light emitting unit 8 irradiates the light receiving unit 9 with light, and the light receiving unit 9 changes the amount of light received into a voltage. If the position of the shielding plate 6 changes, the amount of received light also changes, so that the position can be detected. The shielding plate 6 is movable between the light emitting unit 8 and the light receiving unit 9 of the optical analog sensor. Therefore, the shielding plate 6 is configured to move at a position close to the light receiving unit 9 side so as not to be affected by the light wraparound of the light emitting unit 8. Further, the shielding plate 6 is configured to move at a substantially fixed position between the light emitting unit 8 and the light receiving unit 9 by a guide plate or the like (not shown). However, the shielding plate 6 needs to be slightly separated from the light receiving unit 9 because it requires weight and rigidity to suppress the flapping of the paper 2 due to the blown air. For this reason, the light from the light emitting unit 8 may wrap around, and accurate detection may not be possible. Therefore, as shown in FIG. 4, an elastic shielding member 10 is added to the shielding plate 6 to contact the light receiving unit 9.

JP-A-7-187422 JP-A-10-95543 JP 2000-188420 A

  However, in the configuration of FIG. 4, the elastic shielding member 10 is affixed in parallel with the movable direction of the shielding plate 6, but is opposite to the surface in contact with the elastic shielding member 10 and the light receiving surface 9 of the optical analog sensor 7. Affixed to the surface (C and D in FIG. 4). That is, the surface C that contacts the elastic shielding member 10 and the light receiving portion 9 of the optical analog sensor 7 is the opposite surface to the surface (attachment surface) D that contacts the elastic shielding member 10 and the shielding plate 6. . For this reason, when the elastic shielding member 10 is repeatedly contacted and moved, a force is applied to the attaching surface like a wedge, and the elastic shielding member 10 is lifted or peeled off.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a stable and highly reliable paper feeding device by preventing the elastic shielding member from being lifted and peeled off.

  The object is to make the shape of the shielding plate for detecting the position of the upper surface an inverted U shape, the elastic shielding member is arranged in parallel with the movable direction of the shielding plate, and the elastic shielding member and the light receiving surface of the optical analog sensor The contact surface is arranged so as to be the same surface as the contact surface (attachment surface) between the elastic shielding member and the shielding plate.

  According to the present invention, it is possible to provide a stable and highly reliable paper feeding device that can prevent the shielding member from being lifted, peeled off, and the like by inexpensive and simple attachment.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 shows a side view of an embodiment of the present invention. FIG. 2 is an enlarged view of part A of FIG. 1 as viewed from the B direction. 1 and 2, the same reference numerals as those in FIGS.

  1 and 2, 6a is a shielding plate, and 10a is an elastic shielding member. As shown in FIG. 5, the lower part of the shielding plate 6a is formed in an inverted U shape in parallel with the movable direction. As shown in FIG. 2, the elastic shielding member 10a is arranged in parallel with the movable direction of the shielding plate 6a, and the surface C where the elastic shielding member 10a and the light receiving surface 9 of the optical analog sensor 7 are in contact is elastic. The shielding member 10a and the shielding plate 6a are pasted so as to be in the same plane as the surface D (C and D in FIG. 2).

  In this embodiment, the lower part of the shielding plate 6a is formed in an inverted U shape. However, for example, as shown in FIG. 6, a square hole 6b is provided in the shielding plate, and the elastic shielding member 10a is placed in the square hole 6b. The same effect can be obtained even if the configuration is passed.

  As described above, the surface C where the elastic shielding member 10a and the light receiving portion 9 of the optical analog sensor 7 are in contact is the same surface as the surface D where the elastic shielding member 10a and the shielding plate 6a are in contact. The elastic shielding member 10a is guided and protected on the upper side of the reverse U-shape of the shielding plate 6a by sticking the elastic shielding member 10a to the lower part of the shielding plate 6a through the U-shaped space. In addition, a load is not applied to the pasted portion even with repeated movement.

It is a side view which shows one Example of this invention paper feeder. It is the enlarged view which looked at the A section of FIG. 1 from the B direction. It is a side view which shows an example of the conventional paper feeder. It is the enlarged view which looked at the A section of FIG. 3 from the B direction. It is a figure which shows the shape of the shielding board of this invention. It is a figure which shows the shape of the other shielding board of this invention.

Explanation of symbols

  1 is a tray, 2 is a sheet, 3 is a top sheet, 4 is an air ejection mechanism, 5 is a suction conveyance mechanism, 6 and 6a are shielding plates, 7 is an optical analog sensor, 8 is a light emitting unit, and 9 is a light receiving unit. 10 and 10a are elastic shielding members.

Claims (1)

Consists of air blowing means that floats and separates the top of the paper loaded in the tray, and a transport belt that sucks and transports the top paper on the tray, and detects the top surface of the top paper In order to keep the upper surface position of the uppermost sheet at a constant position using an optical analog sensor, an elastic shielding member is disposed on a shielding plate that moves together with the upper surface of the sheet and detects the upper surface position. In the paper feeding device in contact with the light receiving surface of the optical analog sensor,
The elastic shielding member is arranged in parallel with the movable direction of the shielding plate, and the elastic shielding member and the shielding plate are in contact with the elastic shielding member and the light receiving surface of the optical analog sensor. A sheet feeding device arranged to be flush with the surface.

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