JP4595945B2 - Operation panel and image forming apparatus - Google Patents

Description

  The present invention relates to an operation panel that covers a printed board with a case, and an image forming apparatus that uses the operation panel.

  2. Description of the Related Art Conventionally, for example, an electronic device such as a multifunction peripheral has an operation panel for inputting data. The operation panel includes a printed circuit board on which an electronic circuit unit composed of various electronic components is mounted, and covers the printed circuit board with a case in order to protect the various electronic components from static electricity.

  The printed circuit board is provided with a ground pattern at the outer peripheral edge outside the mounting area of the electronic circuit section, and a resistance member is disposed at a position where the case is closest to the ground pattern. The discharge impedance between the case and the resistance member is made substantially the same as the discharge impedance of the part. Therefore, even if static electricity arrives from the outside through the gap of the case to the printed circuit board, the static electricity is surely discharged to the nearest ground pattern from the arrival site, so that various electronic components on the printed circuit board can be protected from static electricity. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 10-214697

  However, the conventional operation panel requires a resistance member in addition to various electronic components constituting the electronic circuit unit, and has a large number of components. In addition, it is troublesome to solder the resistance member to the printed circuit board. As described above, the conventional operation panel has a large number of parts and takes a lot of time to create a printed circuit board, which is expensive.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an inexpensive operation panel and image forming apparatus.

The operation panel according to the present invention has the following configuration.
(1) In an operation panel including a printed circuit board on which an electronic circuit unit composed of various electronic components is mounted and a case covering the printed circuit board, the printed circuit board is electrically protected by a carbon pattern and a metal stay. The pattern is formed in a loop shape so as to surround the electronic circuit portion, the case is formed with a locking hole for locking a cover attached to cover the case, and the metal stay is formed of the carbon pattern. It has higher conductivity and is disposed at a position corresponding to the locking hole .

( 2 ) In an operation panel comprising a printed circuit board on which an electronic circuit unit composed of various electronic components is mounted, and a case covering the printed circuit board, the case is attached so that a plurality of covers can be replaced, A locking hole for locking the cover is formed, and the printed circuit board is formed in a loop shape so that an electric protection pattern composed of a carbon pattern and a metal stay surrounds the electronic circuit portion, and the metal The night has higher conductivity than the carbon pattern and is arranged at a position corresponding to the locking hole.

( 3 ) In the invention described in ( 2 ), the plurality of covers have different languages printed on the surface.

( 4 ) In the operation panel described in any one of (1) to ( 3 ), the electronic circuit unit includes a switch contact formed of carbon, and the carbon pattern includes the switch contact and It was formed at the same time.

( 5 ) Further, an image forming apparatus according to the present invention includes the operation panel described in any one of (1) to ( 4 ).

  In the operation panel of the present invention having the above configuration, static electricity discharged between the case and the printed circuit board from the outside is preferentially discharged to the metal stay in the electronic circuit portion, and flows from the metal stay to the loop-like carbon pattern. Is consumed while circling the carbon pattern. Even if static electricity flows around the electronic circuit portion along the carbon pattern, since the conductivity of the carbon pattern is lower than that of the metal stay, the electrical protection pattern composed of the carbon pattern and the metal stay does not become a noise antenna. Therefore, according to the operation panel of the present invention, it is possible to protect various electronic components by discharging static electricity to the electrical protection pattern without soldering a resistance member to the printed circuit board separately from the various electronic components constituting the electronic circuit. The number of parts and the labor for creating a printed circuit board can be reduced, and the cost is low.

  Even if the static electricity is discharged from the outside to the printed circuit board through the locking hole formed in the case to lock the cover, the operation panel of the present invention is static on the metal stay near the locking hole. Is surely discharged. Therefore, according to the operation panel of the present invention, various electronic components can be protected from static electricity with a simple structure in which the electrical protection pattern is formed so that the metal stays are arranged at positions corresponding to the locking holes.

  The operation panel of the present invention, for example, arranges a metal stay at a position corresponding to the locking hole for locking the cover, even when the user attaches a cover printed with a desired language without wearing anti-static gloves to the case. Therefore, static electricity can be reliably discharged to the electrical protection pattern.

  Since the operation panel of the present invention forms the carbon pattern simultaneously with the switch contacts formed in the electronic circuit portion, even if the carbon pattern is increased on the printed circuit board, the man-hour for creating the printed circuit board does not increase.

  Since the image forming apparatus of the present invention has the inexpensive operation panel as described above, the apparatus cost can be reduced.

  Next, an embodiment of an operation panel and an image forming apparatus according to the present invention will be described with reference to the drawings.

<Overall configuration of multifunction device (image forming apparatus)>
FIG. 1 is a partial cross-sectional view of a multifunction machine 1 that is an example of an “image forming apparatus”.
The multifunction device 1 has a plurality of functions such as a copy function, a scanner function, a print function, and a facsimile function. The multifunction machine 1 includes an image forming unit 2 for forming an image on a recording sheet and an image reading unit 3 for reading an image of a document. The image reading unit 3 is rotatably attached to the image forming unit 2. An operation panel 10 is attached to the front side of the image reading unit 3.

  For example, when the user sets a document on the image reading unit 3 and inputs a copy start command from the operation panel 10, the multifunction device 1 reads the document and acquires image data. In the image forming unit 2, as indicated by a one-dot chain line in the figure, the paper feeding unit 4 picks up one recording sheet from the paper feeding cassette 5 and sends it to the image forming unit 6, and an image is recorded on the recording paper based on the image data. After the formation, the recording paper is discharged from the paper discharge unit 7 to a paper discharge tray 8 provided between the image forming unit 2 and the image reading unit 3.

<Overall configuration of operation panel>
FIG. 2 is a plan view of the operation panel 10.
The operation panel 10 is unitized in order to improve assemblability. In the operation panel 10, a plurality of dust keys 11 for inputting data are exposed on the surface of the cover 15, and a display panel 12 for displaying data is covered with a transparent cover.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 4 is a cross-sectional view taken along line BB in FIG. 3 and 4 are enlarged and displayed from FIG. 2 in order to make the drawings easy to see.
The operation panel 10 is configured by stacking a printed circuit board 13, a case 14, and a cover 15. As shown in FIG. 3, the printed circuit board 13 is hooked and held by a claw portion 16 protruding from the back surface of the case 14.

  As shown in FIGS. 3 and 4, a rubber sheet 17 is disposed between the printed circuit board 13 and the case 14. The rubber sheet 17 covers the surface of the printed board 13 and is insulated.

  A plurality of rubber keys 11 are provided on the surface of the rubber sheet 17 so as to protrude from the surface. The rubber key 11 is formed in a rectangular parallelepiped block shape, and the strength is secured so as not to be deformed when pressed. Each rubber key 11 is integrally connected to the rubber sheet 17 via the flexible portion 18.

  The flexible portion 18 is formed in a square frame shape along the outer periphery of the side surface of the rubber key 11 facing the printed circuit board 13 so that the connecting portion on the rubber sheet 17 side of the flexible portion 18 is larger than the connecting portion on the rubber key 11 side. The sides are inclined. Therefore, the flexible portion 18 has an elastic force in the direction in which the rubber key 11 is pushed up. Each rubber key 11 has a rubber-side contact 19 attached to the lower surface on the side where the flexible portion 18 is formed.

  The case 14 and the cover 15 are made by injection molding of resin. The cover 15 is detachably attached to the case 14. The case 14 and the cover 15 are formed with key holes 14a and 15a through which the rubber key 11 passes.

  As shown in FIG. 4, a plurality of locking claws 20 are provided on the back surface of the cover 15 so as to protrude toward the case 14. The locking claw 20 has a wedge shape in which the tip portion protrudes inward. Since the locking claw 20 is formed of resin, it is slightly deformed outward. The case 14 has a locking hole 14 b and a locking groove 14 c formed at a position corresponding to the locking claw 20. The locking hole 14b is formed so as to penetrate substantially the same width as the locking claw 20, and is formed long in the direction in which the locking claw 20 deforms outward. On the other hand, the locking groove 14 c has the same width as the locking claw 20 and is formed by cutting out the edge of the case 14.

  As shown in FIG. 2, the surface of the cover 15 is provided with a printing surface 26 on which the functions of the rubber keys 11 are printed in a predetermined language in order to clarify the functions of the operation panel 10. The cover 15 is prepared in a plurality of types in which the same content is printed in different languages (for example, Japanese, English, Chinese, etc.) so that the display language can be arbitrarily selected according to the user of the multifunction device 1 and the purpose of use. Has been.

<Electronic circuit configuration of printed circuit board>
FIG. 5 is a conceptual diagram of a wiring pattern provided on the printed circuit board 13 shown in FIG.
The printed circuit board 13 is a resin formed in a plate shape. The printed circuit board 13 has an insulating film formed on the surface, and a wiring pattern is formed on the insulating film. The printed circuit board 13 is mounted with an electronic circuit portion 22 by fixing a plurality of “electronic components” including the switch contacts 21 on the wiring pattern. The printed circuit board 13 has an electrical protection pattern 23 formed in a loop so as to surround the electronic circuit portion 22.

  The electrical protection pattern 23 includes a carbon pattern 24 and a metal stay 25. The carbon pattern 24 is higher in conductivity than the insulating film formed on the surface of the printed circuit board 13 and is formed of the same carbon as the switch contact 21. The metal stay 25 is disposed at a position corresponding to the locking hole 14 b of the case 14. The total length W2 of the metal stay 25 is longer than the total length W1 of the locking hole 14b. The metal stay 25 is made of a material having higher conductivity than carbon (for example, copper).

<Assembly of operation panel 10>
The operation panel 10 overlaps the rubber sheet 17 at a predetermined position on the printed circuit board 13. Further, the display panel 12 is arranged at a predetermined position on the printed circuit board 13. Then, the case 14 is overlaid on the printed circuit board 13 so that the rubber keys 11 pass through the key holes 14a of the case 14 respectively. Then, the claw portion 16 of the case 14 is hooked on the edge of the printed circuit board 13 to position and fix the printed circuit board 13 to the case 14. Then, the case 14 is fixed to the image forming unit 3 with a fixing screw or the like.

  The cover 15 is positioned with respect to the case 14 so as to penetrate the rubber key 11 through the key hole 15a. The cover 15 is inserted into the corresponding locking holes 14b and the locking grooves 14c of the case 14 while elastically deforming the locking claws 20 outwardly, thereby restoring the locking claws 20 and The front end portion is attached to the case 14 by hooking it to the edges of the locking hole 14b and the locking groove 14c. The locking holes 14b and the locking grooves 14c of the case 14 are formed with the same width as the locking claws 20 of the cover 15, and the edges of the locking holes 14b and the locking grooves 14c are directed inward by the locking claws 20. Since the cover 15 is attached to the case 14 so as to be sandwiched, the cover 15 is not displaced with respect to the case 14.

<Effect>
When the user presses down the rubber key 11 protruding from the surface of the cover 15 against the elastic force of the flexible portion 18, the rubber side contact 19 contacts the switch contact 21 of the printed circuit board 13. To send an electric signal. When the user removes his / her finger from the rubber key 11, the rubber key 11 is pushed up by the elastic force of the flexible portion 18, and the rubber side contact 19 is separated from the switch contact 21 of the printed circuit board 13, so that no electrical signal is sent.

  Even when static electricity is generated when the user operates the rubber key 11, the printed circuit board 13 is insulated by covering the surface with the rubber sheet 17, so the gap between the rubber key 11 and the key holes 14a and 15a is obtained. Static electricity is not discharged to the printed circuit board 13.

  Here, the locking hole 14b of the case 14 is formed larger than the locking claw 20 of the cover 15, and the printed circuit board 13 is exposed to the outside through the locking hole 14b. As shown in part P of FIG. 4, a gap is formed between the printed circuit board 13 and the rubber sheet 17 at a portion corresponding to the locking hole 14 b.

  For example, even when static electricity is generated when the cover 15 is attached to the case 14, a metal stay 25 having higher conductivity than the wiring pattern such as the switch contact 21 formed on the printed circuit board 13 is formed around the electric circuit portion 22. The electric circuit portion 22 is disposed closer to the locking hole 14b. For this reason, the static electricity discharged to the locking hole 14 b flows preferentially to the metal stay 25 in front of the printed board 13. The current that flows in the metal stay 25 flows to the carbon pattern 24. Since the electrical protection pattern 23 composed of the carbon pattern 24 and the metal stay 25 is formed in a loop shape, current is consumed while flowing through the electrical protection pattern 23.

Since the electric current flows through the carbon pattern 24 whose current is mainly lower in conductivity than the metal stay 25, the electric protection pattern 23 does not become a noise antenna.
In addition, since the part corresponding to the latching groove 14c of the printed circuit board 13 is blocked by the wall protruding on the back surface of the case 14, static electricity is not discharged.

  Therefore, according to the operation panel 10 of the present embodiment, the static electricity is discharged to the electrical protection pattern 23 without soldering the resistance member to the printed circuit board 13 separately from the various electronic components constituting the electrical circuit unit 22. Since the electronic parts are protected, the number of parts and the trouble of creating the printed circuit board 13 can be reduced and the cost can be reduced.

  By the way, depending on the user of the MFP 1, for example, the language used (for example, Chinese) is different from the language (for example, Japanese) printed on the cover 15, or the language (for example, Japanese) printed on the cover 15 is used. There is a case where it is desired to display a different language (for example, English). The operation panel 10 is provided with a plurality of types of covers 15 that express the same content in different languages (for example, Chinese, Japanese, English, etc.).

  The cover 15 is attached to the case 14 with a simple structure that only hooks the locking claws 20 into the locking holes 14b and the locking grooves 14c of the case 14. Therefore, the user releases the engagement relationship between the locking claw 20 of the cover 15 and the locking hole 14b and the locking groove 14c of the case 14, and the cover 15 on which a certain language (for example, Japanese) is printed. 14, and the locking claw 20 of the cover 15 printed with a desired language (for example, Chinese) is locked in the locking hole 14 b and the locking groove 14 c of the case 14, thereby printing the desired language. The cover 15 having 26 can be easily replaced.

  At this time, the finger of the user who does not wear the antistatic gloves approaches the printed circuit board 13. Even if static electricity is discharged from the outside toward the gap between the printed circuit board 13 and the rubber sheet 17 (see P part in FIG. 4) formed at a position corresponding to the locking hole 14b of the case 14, the electronic component part 22 Static electricity is reliably discharged to the metal stay 25 in front. For this reason, according to the operation panel 10 of the present embodiment, various electronic components are electrostatically charged with a simple structure in which the electrical protection pattern 23 is formed so that the metal stay 25 is disposed at a position corresponding to the locking hole 14b. Can be protected from.

  Moreover, the electrical protection pattern 23 is made of the same carbon as the switch contact 21 formed in the electronic circuit portion 22 of the carbon pattern 24 and is formed simultaneously with the switch contact 21. Therefore, even if the carbon pattern 24 is increased on the printed circuit board 13 and the electronic component part 22 is protected from static electricity, the number of steps for creating the printed circuit board 13 does not increase and the cost is low.

  Note that the multifunction machine 1 including the operation panel 10 can reduce the apparatus cost because the operation panel 10 is inexpensive.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, A various application is possible.
For example, in the above embodiment, the multifunction device 1 is an example of an image forming apparatus. However, the operation panel 10 may be applied to office equipment such as a printer and a copy machine, and home appliances such as a washing machine.
For example, in the above embodiment, the rubber key 11 is provided integrally with the rubber sheet 17. On the other hand, the electrical protection pattern may be formed on the substrate of the operation panel where the key switch is not a rubber key.
In the above embodiment, the locking claw 20 of the cover 15 is hooked on the locking hole 14b of the case 14 and the cover 15 is attached to the case. However, the locking structure of the case 14 and the cover 15 is not limited to this.

1 is a partial cross-sectional view of a multifunction peripheral as an example of an image forming apparatus according to an embodiment of the present invention. Similarly, it is a top view of an operation panel. Similarly, it is AA sectional drawing of FIG. Similarly, it is BB sectional drawing of FIG. Similarly, it is the conceptual diagram of the wiring pattern provided in the board | substrate shown in FIG.

Explanation of symbols

1 MFP (image forming device)
DESCRIPTION OF SYMBOLS 10 Operation panel 13 Printed circuit board 14 Case 14b Locking hole 15 Cover 21 Switch contact 22 Electronic component part 23 Electrical protection pattern 24 Carbon pattern 25 Metal stay

Claims (5)

In an operation panel comprising a printed circuit board on which an electronic circuit unit composed of various electronic components is mounted, and a case covering the printed circuit board,
The printed circuit board is formed in a loop shape so that an electrical protection pattern composed of a carbon pattern and a metal stay surrounds the electronic circuit portion ,
The case is formed with a locking hole for locking a cover attached to cover the case.
The operation panel is characterized in that the metal stay has higher conductivity than the carbon pattern and is disposed at a position corresponding to the locking hole . A printed circuit board electronic circuit unit is mounted consisting of the species electronic components, the operation panel and a case covering the printed board,
The case is attached so that a plurality of covers can be exchanged, and a locking hole for locking the cover is formed,
In the printed circuit board, an electrical protection pattern composed of a carbon pattern and a metal stay is formed in a loop shape so as to surround the electronic circuit portion, and the metal stay has higher conductivity than the carbon pattern , and is formed in the locking hole. An operation panel that is arranged at a corresponding position. In the operation panel according to claim 2 ,
The operation panel, wherein the plurality of covers have different languages printed on the surface. In the operation panel according to any one of claims 1 to 3 ,
The electronic circuit portion has a switch contact made of carbon,
The operation panel according to claim 1, wherein the carbon pattern is formed simultaneously with the switch contact. An image forming apparatus, comprising a control panel according to any one of claims 1 to 4.

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