Button key assembly and electronic apparatus that employs the button key assembly

Button keys, resilient supports and a frame are molded in one piece such that the button keys are resiliently movable and are spaced apart by a gap. Each of the button keys includes an engagement portion. A case includes a button hole formed therein. The case is assembled to the frame such that the button keys are received in the button hole. After the case has been assembled to the frame such that the plurality of adjacent button keys are received in the button hole and such that the engagement portion abuts a perimeter portion of the button hole, the second gap being smaller than the first gap.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a button key assembly of an operator panel incorporated in a variety of electronic equipment including copying machines, facsimile machines, personal computers, telephones, and gaming machines.

2. Description of the Related Art

Conventional electronic apparatuses include an operator panel that employs a variety of operational keys that allow a user to operate the electronic apparatus. Such apparatuses include copying machines, facsimile machines, personal computers, telephones, and gaming machines. An operator panel includes a variety of operational keys such as selection keys for selecting a variety of functions such as “ENTER” and “RETURN” for confirming the selection, and “BACK KEY” for returning to the immediately previous state. These keys are commonly arranged closely for the purposes of functionality and design.

If a plurality of operational keys is to be closely located, the keys should be, for example, molded from a resin material in one-piece construction for minimum manufacturing cost. The mold should be designed such that adjacent keys are spaced apart by a predetermined distance or a gap. This gap may cause the keys to rattle after they have been assembled as a key board, impairing the operability of the keyboard.

SUMMARY OF THE INVENTION

An objection of the present invention is to solve the aforementioned drawbacks, and to provide a keyboard that offers good operability.

Another object of the invention is to provide a keyboard in which adjacent keys are spaced apart by as short a distance as possible so that the operability of the keyboard is least affected and excellent operability is obtained.

A button key assembly, includes a frame, a plurality of adjacent button keys connected to the frame via a plurality of resilient supports such that the plurality of button keys are resiliently movable, and a case.

The plurality of adjacent button keys are connected to the frame via a plurality of resilient supports such that the plurality of button keys are resiliently movable. The plurality of resilient supports, the plurality of button keys, and the frame are formed in one-piece construction, and each of the plurality of button keys includes an engagement portion. The case includes a button hole formed therein. The case is assembled to the frame such that the plurality of button keys are received in the button hole. The plurality of adjacent button keys are spaced apart by a first gap before the plurality of adjacent button keys have been received in the button hole. The plurality of adjacent button keys are spaced apart by a second gap after the case has been assembled to the frame such that the plurality of adjacent button keys are received in the button hole and such that the engagement portion abuts a perimeter portion of the button hole, the second gap being smaller than the first gap.

DETAILED DESCRIPTION OF THE INVENTION

First Embodiment

FIG. 1illustrates a pertinent portion of an image forming apparatus1that employs an operator panel29of a first embodiment.

Referring toFIG. 1, print engines2K,2Y,2M, and2C are aligned in this order in a direction of travel of paper. Transfer rollers10K,10Y,10M, and10C are disposed to face corresponding print engines2K,2Y,2M, and2C, respectively, such that an endless type transport belt18is sandwiched between the print engines2K,2Y,2M, and2C and the corresponding transfer rollers10K,10Y,10M, and10C. The transport belt18is disposed about a drive roller17and a driven roller16. The transfer belt18, drive roller17, and driven roller16cooperate with one another to form a transfer unit27. A paper cassette24holds a stack of paper therein. A feed roller11cooperates with a separator (not shown) to feed the top page of the stack of paper from the paper cassette24. An entrance sensor12and a write sensor13are located upstream of transport rollers14and15with respect to the direction of travel of the paper, and downstream of the transport rollers14and15. A fixing roller19incorporates a heat source such as a halogen lamp, and rotates in contact with a back up roller20so that a toner image on the paper is fused into a permanent image by heat and pressure.

The print engines2K,2Y,2M, and2C include LED heads3K,3Y,3M, and3C, photoconductive drums4K,4Y,4M, and4C, charging rollers5K,5Y,5M, and5C, developing rollers6K,6Y,6M, and6C, toner reservoirs7K,7Y,7M, and7C, developing blades8K,8Y,8M, and8C, and toner supplying rollers9K,9Y,9M, and9Y, respectively. The image forming apparatus1includes the operator panel29at a front portion of the image forming apparatus1, allowing a user to input a variety of settings. The operator panel29will now be described in detail.

FIG. 2is a perspective view of the operator panel29as seen in a direction shown by arrow A ofFIG. 1.

Referring toFIG. 2, a display section30is, for example, a liquid crystal display (LCD), and displays the operational statuses and various settings of the image forming apparatus1. An on-line key34may be switched between a reception mode where the image forming apparatus is ready for receiving information from a host apparatus and a non-reception mode where the image forming apparatus is not ready for receiving information from the host apparatus. A cancel key35is operated by the user if a printing operation should be halted in the middle of printing. Upper and lower menu keys36and37are operated to set the number of pages to be copied and the type of print medium. An enter key38is depressed for confirming various settings after making selection. A back key39is operated if the user wants to return to one immediately previous page of a screen that displays various settings. A help key40is operated for displaying the details of malfunctions such as paper jam. A shut down key41is depressed if the image forming apparatus1is to be turned off. The aforementioned keys depressed by the user are referred to as operational keys hereinafter.

FIG. 3is a front view of the operator panel29.FIG. 4is a cross-sectional view taken along a line B-B ofFIG. 3.FIG. 5Ais a partial expanded cross-sectional view of a portion500ofFIG. 4encircled by a dot-dash line.FIG. 5Bis a partial expanded view ofFIG. 5A.FIG. 5Cis a partial expanded view ofFIG. 5A.FIG. 6is a perspective view of the case33as seen obliquely from above.

Referring toFIGS. 3 and 4, the operator panel29includes a variety of sections in addition to the aforementioned display30and the operational keys34-41. A display cover31is colorless and clear, and covers the front surface of the display30. A circuit board32controls the information received from the operational keys34-41. The case33accommodates the operational keys39-41, display30, display cover31, and circuit board32, and serves as an outer decorated panel. The operational keys34-41each include a pressing portion42. The pressing portion42is immediately over a switch43mounted to the circuit board32. When the operational keys34-41are depressed by the user, the switches43are shifted to their ON-position or OFF-position.

An on-line key34, the cancel key35, upper menu key36, the lower menu key37, the back key39, the enter key38, and a frame44are molded from, for example, a synthetic resin material in one piece construction such that these elements form a button key assembly45as a whole. The button keys assembly45will be described in more detail.

FIG. 7is a front view of the button key assembly45.FIG. 8is a perspective view of the button key assembly45as seen obliquely from above.

The operational keys34-39are in one piece with resilient supporting arms36f,36g,39d,39e,37g, and37fand the frame44such that the operational keys34-39may be displaceable by a predetermined short distance. Supporting arms36fand36gare formed between the upper menu key36and the frame44. Supporting arms37fand37gare formed between the lower menu key37and the frame44. Supporting arms39dand39eare formed between the back key39and the frame44. It is to be noted that the upper key36, lower key37and back key39are spaced apart from one another by a predetermined distance or a first gap T1(e.g., 0.8 mm,FIGS. 7 and 12) before the button key assembly45has been assembled to the case33. It is important that a mold used for one-piece molding of the button key assembly45has sufficient mechanical strength in all structural portions. In order to ensure sufficient mechanical strength of the mold, the portions of the mold corresponding to the first gap T1should have a minimum, sufficient thickness. The configuration of the aforementioned operational keys34-39having the first gap T1ensures mechanical and structural strength of the mold used for one-piece molding. The supporting arms each have one end fixed to the frame44and another end fixed to the corresponding operational keys, thereby supporting the operational keys such that the operational keys are resiliently movable in directions parallel to the direction in which the operational keys are depressed and in the directions substantially perpendicular to the directions in which the operational keys are depressed.

FIG. 9is a perspective view of the button key assembly45as seen obliquely from above.

Thus, as shown inFIG. 9, the first gap T1exists between a back key wall portion39bthat extends from the surface of the back key39in a direction in which the back key39is depressed, and an upper menu key wall36cthat extends in the direction in which the upper menu key36is depressed. The first gap T1also exists between the back key wall portion39bthat extends in the direction in which the back key39is depressed, and the lower menu key wall37cthat extends from the surface of the lower menu key37cin the direction in which the lower menu key37is depressed.

Referring toFIGS. 5A-5B,7, and8, abutments36dand36eare formed on side surfaces36aand36bof the upper menu key36. The abutments36d(FIG. 5A) and 36ehave short beveled surfaces46a(FIG. 5C) that facilitate the movement of the upper menu key36when the button key assembly45is assembled to the case33. Abutments37d(FIG. 8) and 37care formed on side surfaces37aand37bof the lower menu key37. The abutments37dand37ehave beveled surfaces46b(not shown) that facilitate the movement of the lower menu key37when the button key assembly45is assembled to the case33. An abutment39c(FIGS. 5 and 8) is formed on a side surface39aof the back key39, and has beveled surfaces46c(FIG. 5B) that facilitate the movement of the back key39. The beveled surfaces46a-46cshould be formed at positions where the beveled surfaces are below the surface of the case33after the button assembly45has been assembled the case33for pleasant appearance of the keyboard.

FIG. 10illustrates the operation of the button key assembly45. Referring toFIG. 10, the supporting arm36gand the supporting arm36fconnect the frame44and the upper menu key36together. The supporting arm36gand the supporting arm36finclude knee bends36k(sharply curved portions) and36nand36m, respectively, for providing resiliency that allows the upper menu key36to resiliently displace in directions shown by arrows U1and U2. Likewise, the supporting arm37gand the supporting arm37fconnect the frame44and the lower menu key37together. The supporting arm37gand the supporting arm37finclude knee bends37k(sharply curved portion) and37nand37m,respectively, for providing resiliency that allows the lower menu key37to resiliently displace in directions shown by arrows L1and L2. Still likewise, the supporting arm39dand the supporting arm39econnect the frame44and the back key39together. The supporting arm39dand the supporting arm39einclude knee bends39fand39g(sharply curved portion) and knee bends39hand39i, respectively, for providing resiliency that allows the back key39to resiliently displace in a direction shown by arrow B1.

As described above, the upper menu key36, lower menu key37, and back key39each include at least one knee bend in their corresponding supporting arms such that the knee bend provides resiliency of the key in specific directions. In other words, when external forces are exerted on the upper menu key36, lower menu key37, and back key39, the knee bends resiliently deform such that these keys are allowed to resiliently displace in the U1and U2directions, the L1and L2directions, and the B1direction, respectively.

FIG. 11illustrates an angle θ through which a portion102curves relative to a portion101about a bent portion100. The respective knee bends are bent by the angle θ equal to or greater than 90 degrees and not larger than 180 degrees so that the respective supporting arms may be resiliently deformed without difficulty.

Referring back toFIGS. 3 and 4, the frame44includes a first post47(FIGS. 4 and 7) and a second post48that are located at longitudinal end portions of the frame44and at substantially midway between widthwise ends of the frame44. When the button key assembly45is assembled to the case33(FIG. 6), the first and second posts47and48are fittingly received in a circular recess49and an elongated circular recess50, respectively. The display section30is electrically connected to a circuit board32via cables (not shown). The display section30and the display cover31are securely mounted to the case33by means of, for example, screws (not shown) such that the display cover31covers the front side of the display section30.

The circuit board32includes a round hole51and an elongated hole52spaced apart by a predetermined distance. The case33includes a first post53and a second post54formed thereon, and received in the round hole51and elongated hole52, respectively. The circuit board32is fixed to the case33by means of, for example, screws.

Referring toFIG. 6, the case33includes a single button hole56for receiving the upper menu key36, lower menu key37, and back key39therein, and includes no partitions that isolate these operational keys from one another. The button hole56has a perimeter portion56aand a perimeter portion56b.

The engagement relation among the button hole56, the abutments36dand36eof the upper menu key36, the abutments37dand37eof the lower key37, the abutment39cof the back key39will be described.

The upper menu key36, lower menu key37, and back key39are spaced apart from one another by the first gap T1(e.g., 0.8 mm) before the button key assembly45is assembled to the case33. The side surface36aof the upper menu key36, side surface37aof the lower menu key37, and side surface39aof the back key39have a radius of curvature substantially the same as the surface of the perimeter portion56aof the button hole56, so that the side surfaces36aand37amay comfortably slide on the perimeter portion56aonce the button key assembly45has been assembled to the case33. Likewise, the side surface36bof the upper menu key36and the side surface37bof the lower menu key37have a radius of curvature substantially the same as the surface of a perimeter portion56bof the button hole56, so that the side surfaces36band37bmay comfortably slide on the perimeter portion56b.

The relation between the diameter of the perimeter56aof the button hole56, and the radii of the upper menu key36, lower menu key37, and back key39will be described with reference toFIGS. 12A-12C.FIG. 12Aillustrates the various dimensions of the button hole56.FIG. 12Billustrates the various dimensions of the upper menu key36, lower menu key37and back key39before the button key assembly45has been assembled to the case33.FIG. 12Cillustrates the positional relationship among the upper menu key36, lower menu key37and back key39after the button key assembly45has been assembled to the case33.

Referring toFIG. 12A, the perimeter portion56aincludes a diameter D1equivalent to the diameter of an imaginary circle A (centered at “201”), and the perimeter portion56bincludes a diameter D3equivalent to the diameter of an imaginary circle B (centered at “202”). The center-to-center distance W between the two imaginary circles A and B is selected such that the two imaginary circles A and B overlap each other by a predetermined amount.

Referring toFIG. 12B, the upper menu key36, lower menu key37, and back key39are spaced apart from one another by the first gap T1(e.g., 0.8 mm) before the button key assembly45has been mounted to the case33, and the side surface36a, side surface37a, and side surface39ahave a radius of curvature substantially the same as that of the imaginary circle A having the diameter D1about the center201. Further, the abutments36d,37d, and39cproject further radially outwardly than the diameter of the perimeter portion56aof the button hole56, i.e., an imaginary circle C that is circumscribed around the abutments36d,37d, and39chas a diameter D2slightly larger than the diameter D1. The diameters D, D2, D3, and D4are 33mm, 33.6 mm, 21.6 mm, and 21 mm in the first embodiment.

The imaginary circle B having the diameter D3lies on the side surface36bof the upper menu key36and the side surface37bof the lower menu key37. An imaginary circle D that is circumscribed around the abutments36eand37ehas a diameter D4slightly smaller than the diameter D3. In other words, the abutments36eand37eproject from the upper menu key36and lower menu key37radially outwardly from the center201further than the perimeter portion56bof the button hole56before the button key assembly45has been assembled to the case33. It is to be noted that the upper menu key36and lower menu key37are on either side of an imaginary plane cutting through the passing through the first and second posts47and48and generally perpendicular to the front surface of the case33, and are mirror images of one another. Another way of looking at the assembly is that the upper menu key36and lower menu key37are symmetrical with respect to a line passing through the centers201and202. Likewise, the back key39is symmetrical about the line passing through the centers201and202.

As described above, a second gap T2smaller than the first gap T1is maintained between the perimeter portion56aand the surface36a, between the perimeter portion56aand the side surface37a, and between the perimeter portion56aand the side surface39a. The radius of curvature of the perimeter portion56bis substantially equal to that of surface36band side surface37b. The side surfaces36aand37amay be any shape as long as they do not outwardly extend further from the center201than the imaginary circle C having the diameter D2. The side surfaces36band37bmay be of any shape as long as they do not outwardly extend further from the center201than the imaginary circle D having the diameter D4.

For example, if the perimeter portion56aof the button hole56has a diameter of 33 mm, and the perimeter portion56bof the button hole56has a diameter of 21.6 mm, then the side surfaces36a,37a, and39aare designed to have a diameter of 33 mm, the side surfaces36band37bare designed to have a diameter of 21.6 mm, the abutments36d,37d, and39care designed to be inscribed in the imaginary circle having a diameter of D2=33.6 mm, and the abutments36eand37eare designed to be on the imaginary circle D having a diameter of D4=21 mm. These diameters are those before the button key assembly45has been assembled to the case33.

The operation of the button keys of the aforementioned configuration will be described.

When a user wants to select, for example, the number of pages to be printed and the type of a medium to be printed on, he depresses the upper menu key36, lower menu key37, and back key39to select appropriate settings. As described previously, once the first post47and the second post48have been fittingly received in the circular recess49(FIG. 4) and the elongated circular recess50, respectively, the first post47and second post48are positioned accurately in a plane normal to the direction in which the operational keys are pressed.

The surfaces of the abutments36d,37d, and39care inscribed in the imaginary circle C having the diameter D2larger than the diameter of the perimeter portion56a.Therefore, when the upper menu key36, lower menu key37, and back key39are inserted in the button hole56, the abutments36d,37d, and39cabut the perimeter portion56aof the button hole56. Because the surfaces of the abutments36eand37eare on the circumference of the imaginary circle D having a diameter D4smaller than the perimeter portion56bof the button hole56, the abutments36eand37eare pressed against the perimeter portion56bof the button hole56.

When the button key assembly45has been assembled to the case33, the upper menu key36, lower menu key37, and back key39are pushed by the perimeter portions56aand56bin the U1and U2directions, L1and L2directions, and B1direction, respectively, as shown inFIG. 10. Thus, the knee bends36k,36n,36m,37k,37n,37m,39f,39g,39h, and39iresiliently deform such that the upper menu key36, lower menu key37, and back key39are displaced in such directions as to reduce the gap between adjacent ones of these keys from the first gap T1(e.g., approx. 0.8 mm) to the second gap T2(e.g., approx. 0.2 mm).

Once the upper menu key36, lower menu key37, and back key39have been assembled to the case33, the second gap T2between adjacent ones of these keys36,37,39is smaller than the first gap T1(e.g., 0.8 mm), the difference in gap being equal to the difference between the diameter of the button hole56and the diameter of the imaginary circle C in which the abutments36d,36e,37d,37e, and39care inscribed. The decrease in the gap in this manner is effective in minimizing rattling of the operational keys after the button key assembly45has been assembled to the case33. The difference is approx. 0.6 mm, providing that the perimeter portions56aand56bhave diameters of 33 mm and 21.6 mm, respectively, and the abutments36d,37d, and39care inscribed in the imaginary circle C having a diameter of 33.6 mm, and the surfaces of abutments36eand37eare on the circumference of the imaginary circle D having an outer diameter of 21 mm.

In the first embodiment, the abutments36d,36e,39c,37d,37eof the respective operational keys abut the perimeter portions56aand56bof the button hole56, thereby decreasing the gaps from the first gap T1to the second gap T2. However, the invention is not limited to this. For example, the abutments of the respective operational keys may abut other portions of the case33than the perimeter portions56aand56bof the button hole56, so that the first gaps T1decrease to the second gaps T2.

As described above, when the upper menu key36, lower menu key37, and back key39have been inserted into the button hole56, the abutment36d,36e,37d,37e, and39cabut the perimeter portions56aand56b, so that the gaps between adjacent ones of the upper menu key36, lower menu key37, and back key39may be decreased from the first gap T1to the second gap T2. Thus, the rattling of the operational keys due to the smaller second gaps T2between adjacent ones of the operational keys is minimized. For example, the configuration is effective in minimizing the rattling of the operational keys in directions perpendicular to the direction in which the operational keys are depressed, thereby improving the operability of the operational keys.

The first embodiment allows the operational keys to be spaced apart by the sufficiently large gap (e.g., T1shown inFIG. 7) during the manufacture of the button key assembly45by molding. Thus, the mold for molding the operational keys may be designed to have sufficient mechanical strength.

Second Embodiment

FIG. 13is a front view illustrating an operator panel129of a second embodiment.

FIG. 14is a cross-sectional view taken along a line B-B ofFIG. 13.

FIG. 15is a partial expanded view of an area depicted at500shown inFIG. 13.

FIG. 16is a perspective view of a button key assembly145as seen obliquely from above.

FIG. 17is a perspective view of the button key assembly145as seen obliquely from under.

Referring toFIG. 13, the operator panel129differs from the operator panel29in the configuration of an upper menu key136, a lower menu key137, and a back key139. Elements similar to those in the first embodiment have been given the same reference numerals and their description is omitted. The configuration of the image forming apparatus1of the second embodiment is the same as that of the image forming apparatus1of the first embodiment except for the operator panel129. Thus, the second embodiment will be described with reference toFIG. 1as required.

Just as in the first embodiment, the upper menu key136and lower menu key137are on either side of an imaginary plane cutting through the passing through the first and second posts47and48and generally perpendicular to the front surface of the operator panel129, and are mirror images of one another. Another way to look at this configuration is that the upper menu key136and lower menu key137are symmetrical with respect to an imaginary plane generally perpendicular to the front surface of the operator panel129. The back key139is also symmetrical with respect to the imaginary plane. Referring toFIGS. 15-17, the upper menu key136includes a projection136athat extends over a distance substantially equal to a half of the thickness of an upper portion of the upper menu key136, extending in a direction in which the upper menu key136is pressed. There is a predetermined gap or a first gap T1(e.g., 0.8 mm) between a projection139bof the back key139and a side surface136bof the upper menu key136. The upper menu key136includes a side surface136cthat extends from the projection136ain a direction parallel to the direction in which the upper menu key136is pressed. The side surface136cis further away from the projection139bthan the side surface136b.

The upper menu key136further includes a rib136dformed on the side surface136c, the rib136dextending from the projection136ain the direction in which the upper menu key136is pressed. The rib136dincludes a surface flush with the side surface136bof the back key139. In other words, the surface of the rib136dand the side surface136blie in the same plane.

The operation of the button keys of the aforementioned configuration will be described.

In the first embodiment, once the button key assembly45has been assembled to the case33, the second gap T2is only about 0.2 mm. Therefore, when the user depresses the back key39, the back key39is difficult to move while maintaining this small gap T2. As the back key39moves, the back key wall portion39bslides on the upper menu key wall36cand the lower menu key wall37c.

In the second embodiment, the first gap T1between adjacent ones of the upper menu key136, lower menu key137, and back key139is defined by the projection139b, the side surfaces136band137b. In addition, the rib136dis flush with the side surface136b, and extends in a direction parallel to the direction in which the back key139is pressed. The rib137dis also flush with the surface137b, and extends in a direction parallel to the direction in which the back key139is depressed. When the back key139is depressed, the projection139bslides on the rib136dand the rib137d. The remaining portion of the operation is the same as that described in the first embodiment, and the description thereof is omitted.

When one of the upper menu key136, lower menu key137, and back key139is pressed, the pressed key moves while being in contact with the adjacent keys. It is to be noted that the pressed key has a smaller total area in contact with the adjacent keys in the second embodiment than in the first embodiment.

As described above, the configuration of the button key assembly145provides substantially the same advantages as the button key assembly45of the first embodiment. The smaller total area of an operational key in contact with the adjacent keys is effective in minimizing the friction between the pressed operational key and the adjacent operational keys, thus facilitating the smooth movement of the pressed operational key. Thus, the configuration of the second embodiment improves the ease of operation of the operational keys.

The first gap T1defined between upper menu key136and the back key139, and the first gap T1defined between the lower menu key137and the back key139do not extend over a great depth, eliminating extremely thin portions of a mold so that the usable lifetime of the mold may be prolonged.

While the embodiments have been described in terms of three operational keys, i.e., upper menu key, lower menu key and back key, the invention is not limited to this. While the operational keys form a generally cylindrical appearance when they are assembled together, the invention is not limited to this. The adjacent operational keys may have any shape.

Although the embodiments have been described with respect to an operator panel of an image forming apparatus, the invention may also be applicable to copying machines, printers, facsimile machines, personal computers, telephones, and gaming machines.