JP4428379B2 - Static electricity removal mechanism for paper cassette - Google Patents

Description

  The present invention comprises a terminal member attached to a paper feed cassette for storing paper, and a grounding portion provided in a cassette receiving portion for mounting the paper feed cassette, and when the paper feed cassette is attached to the cassette receiving portion, The present invention relates to a static electricity removing mechanism for a paper feed cassette that removes static electricity charged in the paper feed cassette when a terminal member contacts a grounding portion.

2. Description of the Related Art Image forming apparatuses such as facsimiles and copiers are provided with a paper feed cassette that stores paper to be supplied to a recording unit that records images. As shown in Patent Document 1, this paper feed cassette is mounted in a drawer shape on a cassette receiving portion provided in the main body of the image forming apparatus, and a flapper for placing paper is placed in the paper feed cassette. A pickup roller is installed at a position above the flapper. As a result, the paper in the paper feed cassette is lifted by the rotation of the flapper and brought into pressure contact with the pickup roller, and is fed out of the paper feed cassette by the rotation of the pickup roller and conveyed to the recording unit.
JP 2003-182875 A

  By the way, in the paper feed cassette as described above, static electricity is generated due to the slide movement of the paper feed cassette and the like when the paper feed cassette is taken out and put in and out for replenishment of paper. Since the generated static electricity is charged to the flapper of the paper cassette, if the paper cassette is returned to the cassette receiving portion in that state, the static electricity flows to other mechanisms of the image forming apparatus, and the recorded image The image quality could be affected. In addition, when the sheet feeding cassette is charged with static electricity, there is a problem that so-called double feeding in which a plurality of overlapping sheets stored in the sheet feeding cassette are simultaneously transported easily occurs.

  Therefore, in order to remove the charged static electricity, there is a paper feed cassette provided with a static electricity removing mechanism. This static electricity removing mechanism has a conductive member having elasticity such as a coil spring attached to the paper feed cassette side and a grounded member such as a sheet metal frame provided on the cassette receiving portion side. When mounted on the plate, the coil spring is elastically contacted with the sheet metal frame, so that the static electricity charged in the sheet feeding cassette is removed.

  However, in the above-described static electricity removing mechanism of the paper cassette, there is a possibility that the static electricity charged in the paper cassette may flow to the ground at a moment when the coil spring contacts the sheet metal frame. If this happens, a large current will flow through the mechanism of the image forming device, which may cause an unexpected situation such as a device reset or malfunction, or a high voltage spark may occur at the contact point between the coil spring and the sheet metal frame. There was sex. In particular, when the static electricity charged in the paper feed cassette is a static electricity having a large charge, the influence of these situations on the image forming apparatus becomes large.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a static electricity removing mechanism for a paper feeding cassette that can safely remove static electricity charged in the paper feeding cassette.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present application includes a terminal member attached to a paper feed cassette for storing paper, and a grounding portion provided in a cassette receiving portion for mounting the paper feed cassette, In the static electricity removing mechanism of the paper feed cassette, the static electricity charged to the paper feed cassette is removed by the terminal member coming into contact with the grounding portion when the paper feed cassette is attached to the cassette receiving portion. The terminal member includes a plurality of contact terminals, and the plurality of contact terminals sequentially contact the grounding portion when the sheet feeding cassette is mounted on the cassette receiving portion. .

  According to a second aspect of the present invention, in the static electricity removing mechanism for the sheet feeding cassette according to the first aspect, the contact terminal is a contact piece having elasticity that protrudes toward the grounding portion and has different elasticity. It is characterized by being.

  According to a third aspect of the present invention, in the static electricity removing mechanism for the paper feed cassette according to the second aspect, the paper feed cassette is configured to be attached in a drawer shape to the cassette receiving portion, and the contact terminals are The sheet feeding cassette is disposed on the outer surface on the back side in the mounting direction, and the grounding portion is disposed on the inner surface on the back side in the mounting direction of the cassette receiving unit.

  According to a fourth aspect of the present invention, in the static electricity removing mechanism of the paper feed cassette according to any one of the first to third aspects, the contact is located at a position where the contact terminal of the grounding portion first contacts. The terminal is provided with a static elimination sheet for removing static electricity charged.

  According to a fifth aspect of the present invention, in the static electricity removing mechanism of the paper feeding cassette according to any one of the first to third aspects, the grounding is provided at a position where the contact terminal of the grounding unit first contacts. It is characterized in that a conductive resistance member made of a material having a lower conductive performance than the portion is attached.

  According to a sixth aspect of the present invention, in the static electricity removing mechanism for the paper feeding cassette according to any one of the first to fifth aspects, the terminal member has the contact terminal provided at one end thereof as the paper feeding. It is arranged outside the cassette, and a connecting portion provided at the other end is connected to a conductive member installed in the sheet feeding cassette.

  According to the first aspect of the present invention, in the static electricity removing mechanism of the paper feed cassette, the terminal member includes a plurality of contact terminals, and when the paper feed cassette is attached to the cassette receiving portion, the plurality of contacts are provided. Since the terminals are in contact with the grounding part in order, even if static electricity with a large charge is charged in the paper cassette, multiple contact terminals come in contact with the grounding part in sequence, and the static electricity is stepped. It is possible to discharge safely and remove it safely. Therefore, it is possible to prevent an unexpected situation such as a reset or malfunction of the device or a high voltage spark from occurring at the contact portion between the terminal member and the grounding portion.

  According to the invention described in claim 2 of the present application, since the contact terminal is a contact piece having elasticity different from each other in the protruding dimensions protruding toward the grounding portion, the contact terminal can be reliably brought into contact with the grounding portion, Static electricity charged in the paper feed cassette can be removed more safely.

  According to the invention described in claim 3 of the present application, the sheet feeding cassette is configured to be attached to the cassette receiving portion in a drawer shape, and the contact terminal is disposed on the outer side on the back side in the mounting direction of the sheet feeding cassette. Since the grounding part is arranged on the inner surface on the back side in the mounting direction of the cassette receiving part, it can be safely removed by discharging the static electricity step by step with the paper feeding cassette with a simple configuration. become able to.

  According to the invention described in claim 4 of the present application, since the static elimination sheet for removing the static electricity charged on the contact terminal is attached at the position where the contact terminal in the ground portion first contacts, the contact terminal contacts the ground portion. The amount of static electricity that flows into the grounding portion instantaneously can be reduced, and the static electricity charged in the paper feed cassette can be removed more safely.

  According to the invention described in claim 5 of the present application, since the conductive resistance member made of a material whose conductivity is lower than that of the grounding portion is attached at the position where the contact terminal in the grounding portion first contacts, the contact terminal is connected to the grounding portion. It is possible to prevent static electricity from abruptly flowing to the grounding portion at the moment of contact with the sheet, and it is possible to more safely remove static electricity charged in the paper feed cassette.

  According to the invention described in claim 6 of the present application, the terminal member has the contact terminal provided at one end thereof arranged outside the paper feed cassette, and the connection provided at the other end is provided in the paper feed cassette. Since it is connected to the conductive member, static electricity charged on the conductive member in the paper feed cassette can be effectively removed by the terminal member.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an image forming apparatus provided with a static electricity removing mechanism for a paper feeding cassette according to an embodiment of the present invention. First, a schematic overall configuration of the image forming apparatus will be described with reference to FIG. The image forming apparatus to which the present invention is applied may be any one of a copier, a facsimile machine, a printer, or a so-called multifunction machine having these functions as long as the image forming apparatus includes a paper feed cassette. . The image forming apparatus 1 shown in FIG. 1 includes a reading unit 2 installed on the upper side and a recording unit 3 installed on the lower side.

  The reading unit 2 includes an image reading device 4 that scans and reads an image of a document, an operation panel 5 attached to the front side of the image reading device 4, and a hinge mechanism whose one side is not shown at the top of the image reading device 4. And a document presser cover 6 attached to be openable and closable. At one end of the document presser cover 6, an automatic document transport device (ADF device) 7 that transports document paper to the image reading device 4 is installed. The ADF device 7 sequentially transports a plurality of documents placed on the document supply tray 8 to the image reading device 4, reads an image of the document by the image reading device 4, and then discharges the document to the document discharge tray 9. It is supposed to be.

  The recording unit 3 is provided with a recording device 10 that records an image on a sheet and a paper feeding device 20 that supplies the sheet to the recording device 10. Although not shown or described in detail, the recording apparatus 10 includes various components such as a developing device, a charging brush, a photosensitive drum, a transfer roller, an exposure head, and a fixing roller arranged along a paper conveyance path formed inside. It is configured with.

  Here, the configuration of the sheet feeding device 20 will be described in detail. As shown in FIG. 1, the paper feeding device 20 includes a paper feeding cassette 30 that stores paper, and a cassette receiving unit 50 that mounts the paper feeding cassette 30 in a drawer shape. The cassette receiving unit 50 is a rectangular opening provided in the lower part of the main body casing 1 a of the image forming apparatus 1. FIG. 2 is a schematic side sectional view showing the paper feeding cassette 30 and the cassette receiving portion 50 (a cross-sectional view seen from the front side in the mounting direction described below), and FIG. 3 is a schematic plan view showing the paper feeding cassette 30. It is. In the following description, as shown in FIG. 3, the direction in which the paper feed cassette 30 is mounted on the cassette receiving unit 50 is referred to as the mounting direction, and the direction in which the paper is conveyed in the paper feed cassette 30 is referred to as the paper feed direction.

  The paper feed cassette 30 is set so that the mounting direction and the paper feed direction are orthogonal to each other. A front cover 31 is provided on the outer surface on the near side in the mounting direction. Further, side walls 32 and 32 and side walls 33 and 33 are provided on both sides of the paper feeding direction and the mounting direction, respectively, and the side walls 32 and 32 are formed linearly along the mounting direction on the outside of the side walls 32 and 32, as shown in FIG. Protruding protrusions 34, 34 are formed, and groove parts 54, 54 with which the protrusions 34, 34 engage are formed on the inner side surfaces 52, 52 of the cassette receiving part 50 facing the side walls 32, 32. Yes. The projecting portion 34 and the groove portion 54 constitute a guide mechanism 55 that guides the sliding movement when the paper feeding cassette 30 is taken in and out of the cassette receiving portion 50.

  As shown in FIG. 3, the inside of the paper feed cassette 30 surrounded by the side walls 32 and 32 and the side walls 33 and 33 is a paper storage unit 35 for storing paper. A flapper 36 which is a flat plate member made of a metal material is installed in the paper storage unit 35. The flapper 36 is installed so as to be rotatable (swingable) in the vertical direction with hinges 37, 37 provided inside the side walls 33, 33 as fulcrums. As shown in FIG. 2, a coil spring 38 interposed between the flapper 36 and the bottom surface 35 a of the paper storage unit 35 is provided on the lower surface side in the vicinity of the front end in the paper feeding direction. Due to the elastic force of the coil spring 38, the front end portion of the flapper 36 is urged upward with the hinge portions 37, 37 as a fulcrum, so as to rotate. Although not shown, a lock mechanism is provided for locking the flapper 36 pushed down against the spring force of the coil spring 38 when the paper is placed on the flapper 36 at the pressed position. Yes.

  As shown in FIG. 3, an end guide 39 and side guides 40, 40 that define the size of the paper placed on the flapper 36 are installed around the flapper 36. The end guide 39 is in contact with the rear end portion of the sheet in the sheet feeding direction, and the side guides 40 and 40 are in contact with both sides of the sheet. The end guide 39 and the side guides 40, 40 are installed so as to be able to advance and retreat along guide grooves 39a, 40a, 40a provided on the bottom surface 35a of the sheet storage portion 35. The end guides 39 and side guides 40, 40 are provided on the guide grooves 39a, 40a, 40a. It can be fixed at an arbitrary position.

  On the other hand, as shown in FIG. 2, a pickup roller 51 that feeds out the sheets stacked on the flapper 36 is installed in the upper part of the cassette receiving unit 50 in the paper feeding direction. The pickup roller 51 is a columnar member whose shape is circular when viewed from the axial direction of the rotating shaft 51 a, and its side surface is a roller surface 51 b, and the roller surface 51 b is a sheet placed on the flapper 36. It is made to rotate by a rotational drive mechanism such as a motor (not shown) while being in contact with the upper surface of the motor.

  Next, the static electricity removal mechanism installed in the paper feed cassette 30 will be described. FIG. 4 is a diagram for explaining the configuration of the static electricity removing mechanism, and is a cross-sectional view taken along the line AA in FIG. 3. As shown in FIGS. 3 and 4, a conductive terminal member 60 is attached to the side wall 33 on the back side in the mounting direction of the paper feed cassette 30. Further, a conductive ground plane 70 is exposed on the inner side surface 53 on the back side in the mounting direction in the cassette receiving portion 50. The terminal member 60 and the ground plane 70 constitute a static electricity removal mechanism that removes static electricity charged in the paper feed cassette 30 when the paper feed cassette 30 is mounted on the cassette receiving portion 50.

  FIG. 5 is a perspective view showing a detailed configuration of the terminal member 60 and the ground plane 70. In the figure, the illustration of the side wall 33 of the paper feed cassette 30 to which the terminal member 60 is attached is omitted. As shown in the figure, the terminal member 60 is a plate spring member integrally formed by bending a plate-like strip made of an elastic metal material. The terminal member 60 has a substantially U-shaped body portion 61 and one end of the body portion 61. And a connection portion 63 having a circular opening 63 a provided at the other end of the main body portion 61. As shown in FIG. 4, the main body 61 is disposed through the communication portion 33 a provided on the lower side so as to connect the inner side and the outer side of the side wall 33, and is exposed to the outer side of the side wall 33. The main body portion 61 connects the contact terminal portion 62 and the connection portion 63 connected to the hinge portion 37 that rotatably supports the flapper 36 in the paper feeding cassette 30. The terminal member 60 is fixed to the side wall 33 with a screw or rivet 65, and the connection portion 63 is connected to the hinge portion 37 with a metal screw or rivet 37a.

  As shown in FIGS. 4 and 5, the contact terminal portion 62 of the terminal member 60 is a portion formed in a brush shape in which one end of the main body portion 61 is branched into a plurality, and protrudes toward the ground plane 70. A first contact piece (first contact terminal) 62a and a second contact piece (second contact terminal) 62b having different projecting dimensions are provided. The first contact piece 62a and the second contact piece 62b have different projecting dimensions that project toward the ground plane 70 due to the different lengths. That is, the length of the first contact piece 62a is longer than that of the second contact piece 62b, and the protruding dimension protruding toward the grounding surface 70 is also larger. In the present embodiment, the second contact piece 62b includes two contact pieces having the same length and shape.

  On the other hand, as shown in FIGS. 4 and 5, the ground contact surface 70 in the cassette receiving portion 50 is the surface of the sheet metal frame 71 disposed on the inner surface 53, and the sheet metal frame 71 is placed in the image forming apparatus 1. It is connected to a grounding component (not shown) provided. And as shown in FIG. 5, the static elimination sheet 72 is affixed in the position where the 1st contact piece 62a contacts in the ground surface 70, ie, the position where the contact terminal part 62 contacts first. This static elimination sheet 72 is a sheet-like member having a function of discharging static electricity into the air when an electrostatically charged object comes into contact. As an example, an organic polymer is formed on the surface of a nonwoven fabric made of ultrafine fibers such as polyester. There is a member formed by reaction formation of a conductive material. In the present embodiment, the static elimination sheet 72 is attached only to a position where the first contact piece 62a of the ground surface 70 contacts, and is not attached to a position where the second contact piece 62b contacts.

  In addition to attaching the static elimination sheet 72 as described above to the position where the first contact piece 62a is in contact with the ground plane 70, the illustration is omitted, but it is more conductive than the sheet metal frame 71 constituting the ground plane 70. A conductive resistance member made of a material with low performance may be attached. As the conductive resistance member, there is a sheet-like member made of a material such as metal or carbon having a lower conductive performance than the sheet metal frame 71.

  Next, a procedure for mounting the paper feeding cassette 30 loaded with paper in the cassette receiving unit 50 in the paper feeding device 20 having the above configuration will be described. First, in order to load paper into the paper feed cassette 30, the front cover 31 is pulled toward the front side of the image forming apparatus 1, and the paper feed cassette 30 is pulled out from the cassette receiving unit 50. When the paper feed cassette 30 is pulled out, the flapper 36 in the paper storage unit 35 is pushed down against the elastic force of the coil spring 38 and locked by the lock mechanism. Then, the side guides 40, 40 are moved in a direction approaching each other and stopped at a position that matches the size of the paper to be loaded. In this state, the paper is placed on the flapper 36. When the paper is placed, the paper feed cassette 30 is mounted on the cassette receiving unit 50.

  When the paper feeding cassette 30 is inserted into the cassette receiving portion 50 when the paper feeding cassette 30 is inserted into the cassette receiving portion 50, the contact terminal portion 62 of the terminal member 60 contacts the cassette receiving portion 50. Due to the elastic contact with the ground 70, static electricity charged in the paper feed cassette 30 is discharged to the installed parts of the main body of the image forming apparatus 1 through the terminal member 60 and the ground surface 70.

  At this time, as the sheet feeding cassette 30 slides, the first contact piece 62 a first makes elastic contact with the grounding surface 70 (static elimination sheet 71), and then the second contact piece 62 b makes elastic contact with the grounding surface 70. That is, the first and second contact pieces 62 a and 62 b are in elastic contact with the ground contact surface 70 in order. Accordingly, even if the sheet cassette 30 is charged with a large amount of static electricity, the static electricity is discharged stepwise to the ground plane 70, so that the static electricity can be removed safely. As a result, it is possible to prevent a large current from flowing due to a sudden discharge of static electricity through the mechanical part of the image forming apparatus 1, and to prevent an unexpected situation such as a device reset or malfunction. Further, it is possible to prevent a dangerous situation such as a high voltage spark from occurring at the contact portion between the terminal member 60 and the ground plane 70.

  In addition, as described above, since the static eliminating sheet 72 is attached to the position where the first contact piece 62a contacts the grounding surface 70, when the first contact piece 62a contacts the grounding surface 70, the first contact piece 62a. It is possible to discharge at least part of the static electricity charged in the air. As a result, the amount of static electricity flowing into the ground plane 70 at the moment when the first contact piece 62a contacts the ground plane 70 can be reduced, so that the static electricity can be removed more safely.

  Even when the conductive resistance member is attached to the grounding surface 70 at a position where the first contact piece 62a contacts, instead of the static elimination sheet 72, the first contact piece 62a is connected to the grounding portion 70 by the conductive resistance member. Since the static electricity can be prevented from suddenly flowing to the grounding section 70 at the moment of contact, the static electricity charged in the paper feed cassette 30 can be safely removed. The conductive resistance member is attached only to the position where the first contact piece 62a contacts the ground surface 70, and is not attached to the position where the second contact piece 62b contacts. By doing so, when the second contact piece 62b comes into contact with the ground plane 70, the remaining static electricity charged in the sheet cassette 30 flows smoothly into the ground plane 70, so the sheet cassette 30 is charged. Static electricity is effectively removed without remaining.

  Further, the paper feed cassette 30 is configured to be attached to the cassette receiving portion 50 in a drawer shape, and the contact terminal portion 62 of the terminal member 60 is disposed on the outer side on the back side in the mounting direction of the paper feed cassette 30 and is in contact therewith. Since the ground 70 is disposed on the inner surface on the back side in the mounting direction of the cassette receiving unit 50, when the paper cassette 30 is mounted by sliding, the static electricity is discharged stepwise with a simple configuration. And can be removed safely.

  Further, since the contact terminal portion 62 of the terminal member 60 is composed of contact pieces 62 a and 62 b having different projecting dimensions protruding toward the ground surface 70, the contact terminal portion 62 is changed to the ground surface 70. Can be reliably brought into contact, and static electricity can be removed safely. Further, the terminal member 60 has a contact terminal portion 62 provided at one end disposed outside the paper feed cassette 30 and a connection portion 63 provided at the other end serving as a conductive member in the paper feed cassette 30. 36, the static electricity charged in the paper feed cassette 30 can be collected on the terminal member 60 and effectively removed via the terminal member 60.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims, the specification, and the drawings. Is possible. It should be noted that any shape, structure, and material not directly described in the specification and drawings are within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, the specific configurations of the terminal member and the grounding portion in the static electricity removing mechanism of the present invention are not limited to those shown in the above embodiment. As an example, the number and shape of the contact pieces 62a and 62b included in the contact terminal portion 62 of the terminal member 60 may be other numbers and shapes. Further, as long as the terminal member 60 includes a contact piece that protrudes toward the ground surface 70, the other parts may have a configuration other than the above. The shape of the connecting portion 63 connected to the member may be another shape.

  Further, in the paper storage unit 35 of the paper cassette 30, not only the flapper 36 but also all the conductive members that can be charged with static electricity installed in the paper storage unit 35 directly or through other conductive members. It is desirable to connect to the connection portion 63 of the terminal member 60. By doing so, the static electricity charged in each part of the paper feed cassette 30 can be more effectively removed.

1 is a perspective view illustrating an overall configuration example of an image forming apparatus including a static electricity removing mechanism for a paper feed cassette according to an embodiment of the present invention. It is a sectional side view which shows the structural example of a paper feed cassette and a cassette receiving part. It is a top view which shows the structural example of a paper feed cassette. It is a figure which shows the structural example of a static electricity removal mechanism, and is AA arrow sectional drawing of FIG. It is a perspective view which shows the detailed structural example of the terminal member with which an electrostatic removal mechanism is provided, and a contact surface.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 20 Paper feeder 30 Paper feed cassette 31 Front cover 32 Side wall 33 Side wall 35 Paper storage part 36 Flapper 37 Hinge part 38 Coil spring 39 End guide 40 Side guide 50 Cassette receiving part 51 Pickup roller 53 Inner side surface 60 Terminal member 61 Main body 62 Contact terminal 62a First contact piece (first contact terminal)
62b Second contact piece (second contact terminal)
63 Connection 70 Grounding surface (grounding part)
71 Sheet metal frame 72 Static elimination sheet

Claims (6)

A terminal member attached to a paper feed cassette for storing paper, and a grounding portion provided in a cassette receiving portion for mounting the paper feed cassette, and when the paper feed cassette is attached to the cassette receiving portion, In the static electricity removing mechanism of the paper feeding cassette in which the static electricity charged in the paper feeding cassette is removed by contacting the ground member with the terminal member,
The terminal member includes a plurality of contact terminals, and the plurality of contact terminals sequentially contact the grounding portion when the sheet feeding cassette is mounted on the cassette receiving portion. Static electricity removal mechanism for paper cassette. In the static elimination mechanism of the paper feed cassette according to claim 1,
The static electricity removing mechanism for a sheet feeding cassette, wherein the contact terminals are contact pieces having elasticity different from each other in protruding dimensions protruding toward the grounding portion. In the static elimination mechanism of the paper feed cassette according to claim 2,
The paper feed cassette is configured to be attached to the cassette receiving portion in a drawer shape,
The contact terminal is disposed on an outer surface on the back side in the mounting direction of the paper feed cassette, and the grounding portion is disposed on an inner surface on the back side in the mounting direction of the cassette receiving unit. Static electricity removal mechanism for paper cassette. In the static electricity removal mechanism of the paper feed cassette according to any one of claims 1 to 3,
A static electricity removing mechanism for a sheet feeding cassette, wherein a static elimination sheet for removing static electricity charged on the contact terminal is attached at a position where the contact terminal first contacts in the grounding portion. In the static electricity removal mechanism of the paper feed cassette according to any one of claims 1 to 3,
A static electricity removing mechanism for a sheet feeding cassette, wherein a conductive resistance member made of a material having a lower conductive performance than the grounding portion is attached at a position where the contact terminal in the grounding portion first contacts. In the static electricity removal mechanism of the paper feed cassette according to any one of claims 1 to 5,
In the terminal member, the contact terminal provided at one end thereof is disposed outside the paper feed cassette, and a connection portion provided at the other end is connected to a conductive member installed in the paper feed cassette. A mechanism for removing static electricity from a paper cassette.

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