JP4407669B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a scanner, a facsimile machine, and a copying machine, and more particularly to an image forming apparatus provided with a lock mechanism that locks a reading unit at a predetermined angle with respect to a recording unit.

  2. Description of the Related Art Image forming apparatuses such as scanners, facsimiles, and copiers are generally configured by placing a reading unit that reads a document on a recording unit that performs recording on paper. The reading unit is configured to be opened upward so that the upper surface of the recording unit is exposed when the toner cassette housed in the recording unit is replaced or when a paper jam occurs in the recording unit. Yes.

  A locking mechanism is provided between the recording unit and the reading unit in order to lock the opening when the reading unit is opened at a predetermined angle so that the reading unit is not opened any further.

  FIG. 1 is a perspective view showing a state in which a reading unit 503 on a recording unit 501 is opened in an image forming apparatus 500 having this type of locking mechanism. As shown in the figure, an image forming apparatus 500 places a reading unit 503 that reads a document on a recording unit 501 that performs recording on a sheet, and the reading unit 503 opens with the vicinity of one side as the center of the rotation axis. (See paragraph number “0008” of Patent Document 1). Between the recording unit 501 and the reading unit 503, the reading unit 503 is ejected from the recording unit 501 in a direction to be opened by an elastic unit 507 configured by two torsion springs 505 installed near the axis center. Note that a description of a locking mechanism that locks the reading unit 503 when the reading unit 503 is closed on the recording unit 501 against the elastic force of the elastic unit 507 is omitted.

  A lock mechanism 530 is mounted near one end near the shaft center. The lock mechanism 530 is provided with a shaft support member 535 composed of a male screw on each side of a single bar-shaped lock bar 533 so that the shaft support member 535 can be rotated. It is configured by screwing and fixing to the inner wall surface 509 of the recording unit 501 and the side plate 512 of the mounting plate 511 fixed to the reading unit 503. When the reading unit 503 is closed, the lock mechanism 530 moves the shaft support member 535 in the insertion hole 534 formed of a long hole in which the shaft support member 535 on the inner wall surface 509 side of the lock bar 533 is mounted, whereby the lock bar 533 is moved. Is stored in the recording unit 501. As shown in FIG. 2, the shaft support member 535 is a male thread formed by processing a metal, a screw portion 537 that is screwed into a screw hole provided in the inner wall surface 509 or the side plate 512, and the lock bar. The rotary guide portion 539 has a columnar shape that is rotatably inserted into the shaft 533 and has a diameter larger than that of the screw portion 537, and a head portion 541 provided on an end surface of the rotary guide portion 539.

However, the conventional lock mechanism 530 has the following problems.
(1) Since the shaft support member 535 is a custom-made product having a special structure made by processing a metal as described above, the cost is high.

(2) When the opening / closing operation of the reading unit 503 is repeated many times, the shaft support member 535 is rotated by friction and impact between the shaft support member 535 and the lock bar 533, and the inner wall surface 509 and the side plate 512 of the shaft support member 535 are rotated. There was a risk that loosening would occur in fixing.
JP 2002-72055 A

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus including a lock mechanism that can reduce costs and that does not cause loosening of a shaft support of a lock bar. .

According to the first aspect of the present invention, there is provided a recording unit that performs recording on a sheet, a reading unit that reads an original and is installed on the recording unit so as to be openable and closable, and opens the reading unit at a predetermined angle with respect to the recording unit. A locking mechanism that locks in a closed state. The locking mechanism inserts pivotal support members rotatably into insertion portions provided on both side portions of the lock bar, and records a part of these pivotal support members respectively. In the image forming apparatus configured to be fixed to the scanning unit and the reading unit, at least one of the pair of shaft supporting members constituting the locking mechanism is connected to the recording unit or the reading unit. Comprising a fixed male screw and a resin bush inserted into the insertion portion of the lock bar in a state in which the male screw is inserted , and the lock bar is formed of a resin molded product, Furthermore, the resin bush The material in the image forming apparatus, wherein the surface than the material of the resin of the lock bar is smooth material.

In the invention according to claim 2 of the present invention, the material of the resin bush and the material of the resin lock bar are both polyacetal, and the polyacetal constituting the bush is more than the polyacetal constituting the lock bar. The image forming apparatus according to claim 1, wherein the surface is a high-grade polyacetal having a smooth surface .
According to a third aspect of the present invention, the resin lock bar is formed such that one insertion portion is rotatably supported by inserting the shaft support member, and the other insertion portion is the shaft. It is formed in a long hole shape that allows the support member to be inserted and moved along the longitudinal direction, and the width of the other insertion portion is narrowed near the end portion farthest from one insertion portion. 3. The image according to claim 1, wherein the image is an integrally molded product in which a shaft support member holding hole for holding the shaft support member is formed by providing a pair of locking pieces protruding from the upper and lower inner surfaces. In the forming device.

In the invention according to claim 4 of the present application, the bush includes a lock bar insertion portion that is rotatably inserted into an insertion portion provided in the lock bar, and a flange portion provided on one end surface side of the lock bar insertion portion. an image as defined in claim 1 or 2 or 3, characterized in that through the said flange portion and the lock bar insertion portion is configured by including a through hole for inserting the screw portion of the male thread In the forming device.

  According to the first aspect of the present invention, the frictional resistance between the shaft support member and the lock bar can be reduced by interposing the resin bush, and accordingly, the shaft support of the lock bar by the shaft support member is less likely to be loosened. . Even if the screw is loosened, the bush will rotate, and the loosening of the screw will not occur. Moreover, even for a shaft support member that requires a special shape, the bush can be easily mass-produced at a low cost by using a molding die by making the shape of the bush that is a molded product suitable for it. Low cost general-purpose products available on the market can be used for the male screws made from these products, which reduces the cost of parts that combine male screws and bushes compared to conventional shaft support members that process metal into special shapes. be able to.

According to the first aspect of the present invention, since both the lock bar and the bush are made of resin, it is possible to effectively reduce the frictional resistance between them by using a resin material having a low frictional resistance. it can.

According to the invention described in claim 4 , the outer periphery of the lock bar insertion portion of the bush touches the lock bar insertion portion, and the surface of the collar portion touches the surface of the lock bar on which the shaft support member is inserted. The male screw never touches the lock bar, and the frictional resistance between the lock bar and the shaft support member can be effectively reduced.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 3 is a perspective view showing an example of the image forming apparatus 100 to which the present invention is applied. The image forming apparatus according to the present invention may be any of a copying machine, a facsimile machine, a printer, or a so-called multifunction machine having these functions. The image forming apparatus 100 shown in FIG. 1 includes a recording unit 101 arranged on the lower side and a reading unit 103 arranged on the upper side. The recording unit 101 includes a recording device 105, a paper feed cassette 107, and a recording paper discharge tray 109, and feeds the paper stored in the paper feed cassette 107 to the recording device 105. After recording, the paper is discharged to the recording paper discharge tray 109.

  On the other hand, the reading unit 103 stores a reading device (not shown) in the reading case 111 and reads a document placed on a platen glass (not shown) installed on the upper surface side of the reading case 111. It is comprised so that it may scan and read by. Further, an upper part of the reading case 111 is provided with a document presser cover 113 attached so as to be openable and closable around one side thereof. The document presser cover 113 is configured to press a document placed on the platen glass from above. is doing. An automatic paper feeder (ADF device) 115 that automatically feeds a document is attached to one end of the document pressing cover 113. The automatic paper feeder 115 picks up the documents placed on the document supply tray 117 one by one, and an ADF reading unit (not shown) provided at one end of the upper surface of the reading case 111 by a transport device (not shown). (Not shown), the document is read by a stationary reading device, and then discharged to a document discharge tray 118 provided on the upper surface of the document pressing cover 113. As described above, the reading unit 103 may be a flat bed type scanner that scans a reading device to read a stationary document, or a sheet feed type scanner that reads a document while fixing the position of the reading device. It is comprised so that it can be used.

  FIG. 4 is a perspective view showing a state in which the reading unit 103 on the recording unit 101 is lifted and opened in the image forming apparatus 100. As shown in the figure, the reading unit 103 is mounted on the recording unit 101 so that the vicinity of one side thereof is rotatable about the axis. Between the recording unit 101 and the reading unit 103, an elastic unit 121 including two torsion springs 119 installed in the vicinity of the shaft center is installed. One end of each of the two torsion springs 119 is elastically contacted with the tip of the arm part 133 at both ends of the mounting plate 123 attached to the lower surface of the reading unit 103, and the other end is in contact with the upper surface 125 of the recording unit 101, thereby The reading unit 103 is ejected from the recording unit 101 in the opening direction. It should be noted that a locking mechanism that locks the reading unit 103 when the reading unit 103 is closed on the recording unit 101 against the elastic force of the elastic unit 121 is omitted. The reading unit 103 is opened when the upper surface of the recording unit 101 is exposed to replace a toner cassette or a photosensitive product installed in the recording unit 101, or when the side plate 127 of the recording apparatus 105 is opened to remove the jammed paper. Etc.

  A lock mechanism 200 according to the present invention is mounted near one end near the shaft center. FIG. 5 is an enlarged perspective view of a main part of the lock mechanism 200 shown in FIG. As shown in the figure, the lock mechanism 200 is seen on both side portions of a single synthetic resin lock bar 201, respectively, with a shaft support member 210 (the upper shaft support member 210 is located on the back side of the lock bar 201). And the tip of each of them is fixed to the inner wall surface 129 around the recess 128 provided on the upper surface of the recording unit 101 and the side plate 131 of the mounting plate 123 attached to the reading unit 103. It is installed with. The inner wall surface 129 is made of a metal plate, and a screw hole (not shown) is provided at a predetermined position, and a tip of a male screw 211 described below is screwed and fixed. On the other hand, the mounting plate 123 is made of a metal plate, and its overall shape is substantially U-shaped as shown in FIG. 4, and the tip of the torsion spring 119 is locked to the tip of the arm portion 133 at both ends. Further, the reading unit 103 is configured to be openable and closable with respect to the recording unit 101 by attaching a pivotal support unit 135 provided at the base portion of both arm units 133 to the recording unit 101 so as to be swingable. A screw hole 139 is provided in the vicinity of the tip of the side plate 131 outside the arm portion 133 to screw and fix the tip of a male screw 211 described below.

  6 is a view showing the shaft support member 210. FIG. 6A is a perspective view showing the male screw 211 and the bush 221 constituting the shaft support member 210. FIG. 6B is a view showing the bush 221 from the opposite side. FIG. As shown in this figure, the screw 211 is a commercially available metal male screw that is widely used, and has a columnar screw part 213 and a head having a larger diameter than the screw part 213 formed at one end of the screw part 213. 215. Although not shown, a plus or minus groove for driver engagement is formed on the upper surface of the head 215. Moreover, since the external thread 211 is a commercial item, it is inexpensive.

  The bush 221 is an integrally molded product made of synthetic resin, and has a cylindrical lock bar insertion portion 223 that is rotatably inserted into insertion portions 203 and 205 provided on the lock bar 201 described below, and a lock bar insertion portion 223. Provided on one end surface side (side into which the male screw 211 is inserted) and having a flange portion 225 having a diameter larger than that of the lock bar insertion portion 223, and further passing through the flange portion 225 and the lock bar insertion portion 223. A through hole 227 is formed through the threaded portion 213 of the external thread 211. A head insertion portion 229 is provided at the end of the through hole 227 on the flange 225 side so that the head 215 of the male screw 211 can be inserted with an inner diameter larger than the inner diameter of the through hole 227. The material of the bush 221 is preferably a material whose surface is slippery with respect to the metal, and polyacetal is used in this embodiment. The bush 221 can be easily mass-produced by using a molding die and is inexpensive.

  FIG. 7 is a perspective view showing the lock bar 201, and FIGS. 7A and 7B are perspective views as seen from different surfaces. As shown in the figure, the lock bar 201 is an integrally molded product obtained by molding a synthetic resin in a substantially rod shape, and a pair of through insertion portions through which the lock bar insertion portions 223 of the bush 221 are rotatably inserted on both sides thereof. 203 and 205 are provided. One insertion portion 203 is circular and has an inner diameter dimension that pivotally supports the lock bar insertion portion 223 of the bush 221 inserted into the insertion portion 203. The other insertion portion 205 has a linear long hole shape, and is formed to have a dimension that allows the lock bar insertion portion 223 inserted into the insertion portion 205 to move along the longitudinal direction of the insertion portion 205. In the vicinity of the end portion of the insertion portion 205 farthest from the insertion portion 203, a pair of locking pieces 207 projecting from the upper and lower inner surfaces is provided so as to narrow the vertical width dimension. The end portion of the insertion portion 205 on the side where the locking pieces 207 are provided serves as a shaft support member holding hole 209 having a structure in which the lock bar insertion portion 223 of the bush 221 can be inserted and held at this position. The material of the lock bar 201 is preferably a material whose surface is slippery with respect to a metal, and polyacetal is used in this embodiment.

  Next, a method for attaching the lock mechanism 200 composed of the two sets of shaft support members 210 and one lock bar 201 will be described. First, two sets of shaft support members 210 are assembled by inserting screws 211 into the through holes 227 of the bushing 221 shown in FIG. At this time, the head portion 215 of the male screw 211 is accommodated in the head insertion portion 229 of the bush 221, and the tip of the screw portion 213 protrudes from the end surface of the bush 221 (the end surface on the side where the collar portion 225 is not provided) by a predetermined dimension. To do. Next, the lock bar 201 is disposed between the recording unit 101 and the reading unit 103 as shown in FIG. Then, a pair of pivot members 210 are inserted into the insertion portion 203 on one end side of the lock bar 201 and the tip of the screw portion 213 protruding from the bush 221 is screwed into the screw hole 139 provided in the side plate 131 of the arm portion 133 and fixed. To do. Similarly, another set of shaft support members 210 is inserted into the shaft support member holding holes 209 of the insertion portion 205 of the lock bar 201, and the tips of the screw portions 213 protruding from the bush 221 are provided on the inner wall surface 129 of the recording unit 101. Screw in a screw hole (not shown) and fix.

  In the lock mechanism 200 configured as described above, the state illustrated in FIG. 5 indicates a state in which the reading unit 103 is opened. At this time, the shaft support member 210 fixed to the inner wall surface 129 is located in the shaft support member holding hole 209 of the lock bar 201 and is held in this position by the pair of locking pieces 207, and thus the reading unit. 103 is held in an open state.

  Next, when the reading unit 103 is pressed in the closing direction, the shaft support member 210 is detached from the shaft support member holding hole 209 and moves in the insertion portion 205 formed of a long hole while expanding the pair of locking pieces 207. As a result, the lock bar 201 is accommodated in the recess 128 on the top surface of the recording unit 101, and at the same time, the reading unit 103 is placed on the recording unit 101. When the reading unit 103 is opened, an operation reverse to the above is performed.

  When the lock bar 201 is moved by the opening / closing operation of the reading unit 103, the pair of shaft support members 210 and the insertion portions 203 and 205 of the lock bar 201 into which these members are inserted rotate relatively. As a result, a frictional force is exerted on the shaft support member 210 to rotate it. However, in the case of the present invention, since the bush 221 made of synthetic resin is in contact with the lock bar 201, the friction resistance between the lock bar 201 and the bush 221 is small and slippery between the two, so the bush 221 rotates. do not do. Therefore, the male screw 211 does not rotate, and even if the reading unit 103 is repeatedly opened and closed, the male screw 211 and the inner wall surface 129 of the recording unit 101 and the side plate 131 of the reading unit 103 are fixed by screwing them. There will be no looseness between them. Even if the bush 221 is rotated a little, if the bush 221 is made of a high grade material with a particularly smooth surface (for example, the same polyacetal is expensive, but the surface is smoother). Slip occurs between the male screw 211 and the bush 221, and the male screw 211 does not rotate. Since the bush 221 is a small part, the material used is small, and even if this material is expensive, the cost increase can be suppressed considerably compared to the case where the lock bar 201 itself is made expensive.

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 and the specification and 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 shape and material of the lock bar 201, the external thread 211, and the bush 221 can be variously changed. Although in the above SL embodiments For example the structure of the present invention both of the pair of shaft support 210, the present invention may be applied to only one of the shaft support member 210 as needed.

FIG. 11 is a perspective view showing a conventional image forming apparatus 500 with a reading unit 503 opened. 5 is a perspective view showing a shaft support member 535. FIG. 1 is a perspective view illustrating an example of an image forming apparatus 100 to which the present invention is applied. 1 is a perspective view showing an image forming apparatus 100 with a reading unit 103 opened. 4 is an enlarged perspective view of a main part of the lock mechanism 200. FIG. FIG. 6A is a perspective view showing the male screw 211 and the bush 221 constituting the shaft support member 210, and FIG. 6B is a perspective view of the bush 221 viewed from the opposite side. FIG. FIG. 7A is a perspective view showing the lock bar 201, and FIG. 7A and FIG. 7B are perspective views as seen from different surfaces.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 101 Recording part 103 Reading part 121 Ejection means 123 Mounting plate 129 Inner wall surface 131 Side plate 133 Arm part 139 Screw hole 200 Lock mechanism 201 Lock bar 203 Insertion part 205 Insertion part 207 Locking piece 209 Axial support member holding hole 210 Shaft Support Member 211 Male 221 Bush 223 Lock Bar Insertion Portion 225 Collar Portion 227 Through Hole

Claims (4)

A recording unit that performs recording on a sheet; a reading unit that reads an original and is installed on the recording unit so as to be openable and closable; and a lock mechanism that locks the reading unit at a predetermined angle with respect to the recording unit. The lock mechanism is configured by inserting pivotal support members rotatably in insertion portions provided on both side portions of the lock bar and fixing a part of the pivotal support members to the recording unit and the reading unit, respectively. Image forming apparatus,
At least one of the pair of shaft support members constituting the lock mechanism is configured such that a male screw fixed to the recording unit or the reading unit and a state where the male screw is inserted into the lock bar. A resin bush inserted into the insertion portion , and the lock bar is formed of a resin molded product, and the resin bush is made of the resin lock bar material. An image forming apparatus characterized in that the surface is made of a smooth material . Both the material of the resin bush and the material of the resin lock bar are polyacetal, and the polyacetal constituting the bush is made of a high-grade polyacetal with a smoother surface than the polyacetal constituting the lock bar. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The resin-made lock bar is formed such that one insertion portion is rotatably supported by inserting the shaft support member, and the other insertion portion is inserted along the longitudinal direction by inserting the shaft support member. A pair of latches that protrude from the upper and lower inner surfaces so as to narrow the width dimension near the end portion farthest from the one insertion portion. The image forming apparatus according to claim 1, wherein the image forming apparatus is an integrally formed product in which a shaft support member holding hole for holding the shaft support member is formed by providing a piece. The bush includes a lock bar insertion portion that is rotatably inserted into an insertion portion provided in the lock bar, a collar portion provided on one end surface side of the lock bar insertion portion, the collar portion and the lock bar insertion portion, the image forming apparatus according to claim 1 or 2 or 3, characterized in that through is configured by including a through hole for inserting the screw portion of the male screw a.

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