JP2010030758A - Paper feeder and image forming device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the generation of problematic separating sounds in a separation type paper feeder using a separating pad, and in an image forming device such as a copying machine using the same. <P>SOLUTION: A reinforcing sheet metal 6 is mounted on the reverse side of a paper feed tray 1 (on the reverse side of the separating pad 3 across the paper feed tray 1) to shift the resonance frequency of the paper feed tray 1, thus suppressing separating sounds. Further, a screw fastening site on the reinforcing sheet metal 6 is made selective to adjust the reinforcing effects of the reinforcing sheet metal 6, thus increasing a degree of allowance for suppressing the separating sounds. The size of the reinforcing sheet metal 6 is made selective to be changed corresponding to the generating frequency of the separating sounds. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a sheet feeding device and an image forming apparatus including the sheet feeding device.

  FIG. 1 is an overall view of a copying machine as an example of an electrophotographic image forming apparatus. The overall configuration and operation of such a copying machine are well known, but will be described briefly. A copying machine 100 shown in FIG. 1 is an in-body discharge type copying machine, and is arranged in order of a reading unit 30, an image forming unit 50, and a paper feeding device 70 from the upper side. A space between the image forming unit 50 and the reading unit 30 is formed as a paper discharge storage unit 40, and a sheet on which an image is formed is discharged and stored.

  The image forming unit 50 includes a charging device 11 that charges the surface of the photoconductor 90 around the drum-shaped photoconductor 90, an exposure device 13 that irradiates the surface of the photoconductor 90 with laser light, and a photosensitive device. A developing device 15 for visualizing an electrostatic latent image formed by exposure on the surface of the body 90; a transfer device 17 for transferring a toner image developed on the photoconductor 90 to a sheet; A cleaning device 19 that removes and collects the toner to be recovered is disposed. The photoconductor 90, the charging device 11, the developing device 15, and the cleaning device 19 form one developing unit 21.

  In addition to the above, the image forming unit 50 includes a fixing unit 23 for fixing the toner on the paper to which the toner image has been transferred. The fixing unit 23 is disposed above the developing unit 21 and includes a fixing roller 24 and a paper discharge device 25. The sheet that has passed through the fixing unit 23 is discharged and stored in the discharge storage unit 40 by the discharge device 25.

  In the reading unit 30, a reading traveling body 27 including a light source for illuminating a document and a mirror moves reciprocally with respect to the document placed on the contact glass 29, and reads and scans the document. The image information scanned by the reading traveling body 27 is read as an image signal into a CCD (Charge Coupled Device Image Sensor) 33 disposed behind the lens 31 (right side in the figure). The read image signal is digitized and subjected to image processing.

  Based on the image-processed signal, an optical signal generated by light emitted from an LD (laser diode) in the exposure device 13 reaches the photoconductor 90 via a polygon mirror or lens, and an electrostatic latent image is formed on the surface of the photoconductor 90. It is formed.

  The sheet feeding device 70 includes a sheet feeding tray 35 that is detachably attached to the main body and a sheet feeding roller 39 that is provided on the main body, and is perpendicular to the sheet feeding direction (perpendicular to the paper surface in FIG. 1). Direction) and can be detached from the copying machine 100 main body. The paper feed tray 35 includes a bottom plate 37, a push-up spring 41, a separation pad (separation member) 47, and a pressure spring 49.

  By the way, in the image forming apparatus adopting the separation method using the separation pad as described above, there is a problem of separation sound as a problem that can always occur. That is, since the sheet fed by the sheet feeding roller is brought into sliding contact with the lower surface (or the back surface) and separated by the frictional force, a rubbing sound is generated between the sheet feeding roller or separation pad and the sheet. Such a sound becomes a noise or noise which is very problematic in an office or the like.

  Various solutions have been proposed for preventing such noise from occurring. For example, a weight is attached to prevent the feed roller and the separation pad from vibrating, or separation from the feed roller. Measures such as strengthening the strength of not only the pads but also the members that hold and support them have been implemented.

  However, since the generation conditions of the separated sound differ depending on the paper, environment (ambient environment, installation state, etc.), it is desirable to provide an adjustment mechanism so that it can be optimized even under adverse conditions. However, as the inventor of the present application knows, there is no one that is excellent in the degree of freedom for dealing with separated sound and excellent in cost.

JP 2003-002472 A Japanese Patent No. 40111493 JP 05-238574 A

  In view of the above-described conventional problems, the present invention suppresses separation sound, which is a problem that may occur in a separation type sheet feeding device using a separation pad, and an image forming apparatus such as a copying machine using the separation pad. The purpose is to make it possible.

  A sheet feeding device according to a first aspect of the present invention includes a sheet feeding roller that feeds a sheet from a sheet feeding tray and a separation pad that separates the sheet fed by the sheet feeding roller. A natural frequency variable member such as a sheet metal that can change the natural frequency is added to the holding member and the back side of the holding part that is not in contact with the paper, and the whole natural sheet feeding device or at least the paper feed is provided by the natural frequency variable member. It is characterized in that the natural frequency of the paper feed system formed by the rollers and the separation pad can be increased to suppress or reduce chatter noise during paper feed.

  According to a second aspect of the present invention, in the paper feeding device of the first aspect, the natural frequency varying member is fixed to the back side of the member on which the separation pad is installed with a screw.

  According to a third aspect of the present invention, in the paper feeding device according to the first or second aspect, a plurality of screw fastening portions for fixing the reinforcing sheet metal are provided, and the fastening location can be selected.

  According to a fourth aspect of the present invention, in the paper feeding device according to any one of the first to third aspects, the natural frequency of the natural frequency varying member is changed by changing the size of the member.

  An image forming apparatus according to a fifth aspect uses the paper feeding device according to any one of the first to fourth aspects.

  The image forming apparatus according to claim 6 is any one of a copying machine, a printer, a facsimile machine, and a complex machine thereof.

  The present invention improves the degree of freedom in dealing with separated sound by adding a natural frequency varying member that can vary the natural frequency, such as sheet metal, to provide an adjustment mechanism for the effect of tray reinforcement. The best mode for carrying out the present invention will be described below with reference to the embodiments shown in the drawings.

  FIG. 2 is an enlarged plan view of a sheet feeding device installed in the image forming apparatus. The sheet feeding device 10 includes a sheet feeding tray 1, a sheet feeding roller 2, a friction pad 3, a side fence 4, and an end fence 5.

  A sheet for passing paper is set in a space between the end fence 5 and the sheet feeding roller 3, the sheet is conveyed by the sheet feeding roller 2, and separation is performed by the friction pad 3 so as not to convey a large number of sheets simultaneously. . At this time, the conveyance of the sheet in the vertical direction is performed by the side fence 4, and the conveyance direction is retained by the end fence 5.

  In the separation by the separation pad 3, there is a risk that separation sound due to stick slip on the separation pad 3 is generated, and in order to shift the resonance frequency there, the reinforcing sheet metal 6 is fixed to the back of the tray as shown in FIG.

  On the tray side, as shown in FIG. 3, four positioning bosses 7 and five screw holes 8 are provided. Normally, the positioning boss 7 uses two places on both ends, and the screw hole 8 uses two places on both ends, and three places in the middle. Tighten the points with screws.

  In addition, for the destinations corresponding to the environment / paper with a low frequency of separation sound, priority is given to cost, and the positioning boss 7 uses two places on the inside, and the screw hole 8 uses two places on the inside and three places in the middle. The sheet feeding tray 1 is reinforced with a small-sized sheet metal.

  That is, by attaching the reinforcing sheet metal 6 to the back side of the paper feed tray 1 (the back side of the separation pad 3 across the paper feed tray 1), the resonance frequency of the paper feed tray 1 can be shifted, and as a result, the separation sound is suppressed. be able to. Furthermore, by making it possible to select the screw fastening location of the reinforcing sheet metal 6, it is possible to adjust the reinforcing effect of the reinforcing sheet metal 6 and increase the margin for suppressing the separated sound. In addition, by adopting a configuration in which the size of the reinforcing sheet metal 6 can also be selected, the size of the reinforcing sheet metal 6 can be changed according to the frequency of separation sound generation. Thereby, the whole cost can be reduced. In other words, the cost can be reduced as a whole by using a large-sized sheet metal for an environment in which separation sound is likely to occur or for a paper specification destination, and vice versa.

  If the paper feed tray 1 with the above countermeasures against separation noise is installed as a tray of an image forming apparatus such as a copying machine, the image forming apparatus can also suppress the separation sound. Further, a greater reinforcing effect can be obtained as compared with an example in which ribs are added to the separation peripheral portion reinforcement. Further, since the reinforcing sheet metal 6 is disposed in an unused space on the back side of the sheet feeding tray 1, the above-described reinforcing effect can be obtained without wasting space. In addition, the reinforcement effect can be adjusted by changing the number and location of the screwing portions of the reinforcing sheet metal 6, and the paper compatibility with respect to the separated sound can be improved. As described above, the number of screws is individually increased for destinations and customers who use paper that easily generates separation sound. Further, the size of the reinforcing sheet metal 6 can be selected, and the reinforcing effect can be adjusted by changing the size of the reinforcing sheet metal 6 by providing positioning / fixing screw holes in the sheet feeding tray 1 so that different sizes of sheet metal can be attached.

Overall view of a copying machine as an example of an electrophotographic image forming apparatus Overall view of the front side of the paper tray Illustration of the reinforcing sheet metal attachment on the back side of the paper feed tray Perspective view of reinforcing sheet metal attached and screw tightened Perspective view showing change of reinforcing sheet metal size

Explanation of symbols

1: Paper feed tray 2: Paper feed roller 3: Friction pad 4: Side fence 5: End fence 6: Reinforcing sheet metal 7: Positioning boss 8: Screw hole 9: Fastening screw 10: Paper feed device

Claims (6)

In a paper feeding device having a paper feeding roller for feeding paper from a paper feeding tray and a separation pad for separating paper fed out by the paper feeding roller,
A natural frequency variable member such as a sheet metal that can change the natural frequency is added to the back side of the separation pad or its holding member, which is not in contact with the paper, and the natural frequency variable member can be used to change the entire sheet feeding device or A sheet feeding device characterized in that at least a natural frequency of a sheet feeding system formed by the sheet feeding roller and the separation pad can be increased to suppress or reduce chatter noise during sheet feeding. The paper feeding device according to claim 1.
The natural frequency varying member is fixed to a back side of a member on which a separation pad is installed with a screw. The sheet feeding device according to claim 1 or 2,
A sheet feeding device, wherein a plurality of screw fastening portions for fixing the reinforcing sheet metal are provided, and the fastening locations can be selected. In the paper feeding device according to any one of claims 1 to 3,
A paper feeding device that changes the natural frequency of the natural frequency varying member by changing the size of the member. An image forming apparatus using the sheet feeding device according to claim 1. 6. The image forming apparatus according to claim 5, wherein the image forming apparatus is any one of a copying machine, a printer, a facsimile machine, and a complex machine thereof.