JP2005115184A - Paper feed unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feed unit having a side cover and a paper conveyance guide, in which the operability of an opening/closing mechanism is improved. <P>SOLUTION: The side cover 51 which is opened/closed around a point A and the paper conveyance guide 53 with a press roller 65 which is rotated around a point B are connected together with a link member 52. When the cover is opened, a paper feed conveyance path is uncovered to allow the removal of jammed paper. To close the cover, the locking projection 55a of the cover 51 is brought into contact with the locking part 57 of a machine body with a hop-up spring 58 attached to the paper conveyance guide 53 in a cantilever manner, and thereby the opening/closing mechanism is locked. By pulling back and unlocking the locking projection 55a in order to unlock the opening/closing mechanism, the opening/closing mechanism brings the cover 51 and the paper conveyance guide 53 into opened states by the action of the hop-up spring 58. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to paper feeding for use as an image recording medium in an image forming apparatus such as a printer, a copier, or a facsimile machine, and more particularly to a recording paper feeding unit that is optionally provided in the apparatus body. .

  Conventionally, image forming apparatuses such as printers, copiers, and facsimiles have an additional paper feed unit as an option in addition to the standard cassette-type paper feed unit to respond to the use of multiple sizes and large amounts of paper. To be able to.

  This optional paper feeding unit has the same functions as the paper feeding unit of the equipment main body that is equipped as standard, and is instructed by the control unit of the equipment main body from among all the paper feeding units equipped during operation. The paper feeding operation is performed in response to the selection signal of the used paper feeding cassette. Specifically, the optional paper feeding unit has a structure for loading the main body of the image forming apparatus, is provided in contact with the main body paper feeding unit provided at the lower part of the main body, and is fed by power supplied from the main body side. The mechanism is such that the sheet is guided to a conveyance path common to the sheet feeding unit on the main body side by operating. Further, as means for realizing such conveyance, the optional paper feeding unit side includes a conveyance roller and a guide member similar to those on the main body side.

  By the way, when a jam occurs in the transport path, it is common to deal with such a method that the jammed paper remaining in the transport path is removed by pulling in the paper feeding direction.

In the conventional optional paper feeding unit, the side cover that can be opened and closed, the paper conveying press roller (the roller that presses and conveys the paper between the opposing driving roller) and the upstream side of the press roller The paper conveyance guide part connected to the side is directly attached, and the state of the press roller and the paper conveyance guide part changes from the paper conveyance state where the press roller is pressed against the paper when the cover is closed to the paper conveyance release state when the cover is opened. It has become. Therefore, by opening the cover at the time of jamming, it is possible to perform an operation of opening the press roller together with the paper transport guide portion and removing the jammed paper remaining in the transport path.
For example, in Patent Document 1, a cover body that opens and closes and a moving guide plate with a pressure roller are connected by a link body, and when the cover body is opened, the moving guide plate also opens in conjunction with each other to open the sheet conveyance path. A paper feeder that performs the operation is shown. In addition, by providing a spring that presses the moving guide plate with the pressure roller in the paper direction when the cover is closed, the positioning accuracy can be increased by pressing the moving guide plate against the main body contact surface. Is described.
JP 7-285704 A

  However, the spring shown in Patent Document 1 is provided to press and position a moving guide plate with a pressure roller in the paper direction. For this purpose, this spring is provided between the cover body and the movement guide plate so as to act on the sheet from the back side of the movement guide plate. As can be seen from such a method, the role of the spring is not intended for an operation other than the purpose of positioning the movable guide plate in an appropriate state when the cover body is closed.

  Therefore, the following points are problematic. That is, when the lock state is released to open the cover body, the spring described above is for pressing the movement guide plate toward the paper side for positioning the movement guide plate, and the cover body and movement guide connected by a link. It does not work effectively to move the entire mechanism consisting of plates in the opening direction (the moving guide plate has a spring acting opposite to the opening direction and is not conscious of moving the entire mechanism in the opening direction). It is necessary to be conscious of the operation to open the cover consciously and to apply force, and when closing the cover body, it is normal to keep in mind that it is in a semi-locked state. It can happen that the operation is disturbed.

  SUMMARY OF THE INVENTION In view of such problems, an object of the present invention is to provide a paper feed unit that improves the operability of an opening / closing mechanism including a side cover and a paper transport guide.

  A sheet feeding unit according to the present invention is a recording sheet feeding unit having a structure for loading an image forming apparatus main body and capable of optional equipment, and is set to a sheet conveying state or a sheet conveying path opened state by an opening / closing operation. And a resilient member that urges the guide in a direction to open the guide when the paper transport guide is closed. In addition, a side cover that can be opened and closed is provided, and the paper transport guide unit is set in a paper transport state when the cover is closed or a paper transport path is opened when the cover is opened in conjunction with the side cover. To do. Further, the link between the side cover and the sheet conveyance guide unit is made to be interlocked with each other. Further, the paper transport guide portion includes a press roller used for paper transport and a guide portion provided downstream thereof. Further, the elastic member is arranged at both end portions of the paper transport guide portion. Furthermore, the elastic member is a coil spring that is wound around and attached to a stud protruding from the paper transport guide portion.

  By having the configuration as described above, when the locked state is released, the paper conveyance guide unit automatically moves in the opening direction by the action of the elastic member that urges the paper conveyance guide unit, so that the operator enters the open state. Therefore, it is not necessary to apply much force to the operation for opening the paper transport guide portion, and the operability is improved.

  In addition, even when the side cover is provided and the paper transport guide part has a double structure, both move automatically in the direction of opening, and the movement of the side cover in the opening direction causes the operator to enter the open state. Therefore, it is not necessary to apply much force to the operation for opening the cover, and the operability is improved. If the side cover is not fully locked, the side cover is opened by the action of the elastic member, so that the operator can easily recognize that the side cover is in a semi-locked state and leave it in the half-locked state. Is prevented.

  Further, since the sheet conveyance guide portion opens and closes in conjunction with the side cover via the link, the interlocking operation of both can be reliably performed with a simple structure.

  In addition, since the paper transport guide part has a press roller used for paper transport and a guide part provided downstream thereof, the paper transport path can be effectively opened and the side provided for the purpose of jam processing A configuration suitable for implementation as a cover opening / closing structure can be provided.

  Furthermore, since the elastic members are arranged at both end portions of the paper transport guide portion, the paper transport guide portion can be urged in a stable state, and the paper transport guide can be surely secured even when the side cover is unlocked. It becomes possible to energize the part and move it in the opening direction.

  Furthermore, by using a coil spring wound around and attached to a stud protruding from the paper transport guide portion as an elastic member, it can be easily attached with a simple configuration and can be stably coiled. A spring can be attached.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  The present invention relates to a sheet feeding unit that is optionally combined with an image forming apparatus main body, and has a feature in a side cover opening / closing structure provided in the sheet feeding unit.

  Therefore, prior to the description of the optional sheet feeding unit itself, an embodiment of the overall configuration of the image forming apparatus combined with the image forming apparatus main body in order to use this sheet feeding unit as an option will be described. In the following embodiments, an image forming apparatus having a copying function will be described as an example.

  FIG. 1 is a schematic diagram showing the overall configuration of an image forming apparatus having a copying function according to this embodiment.

  The image forming apparatus main body 100 shown in FIG. 1 has a document reading unit 2 at the top, a recording unit 4, and a sheet feeding unit 3 at the bottom. Further, an optional paper feeding unit 200 is mounted below the apparatus main body 100 so as to stack the main body, thereby constituting the entire image forming apparatus. Although not shown in FIG. 1, the image forming apparatus main body 100 includes an operation panel having an operation unit for inputting an operation condition command to the apparatus and a display unit such as a display for notifying the operation state of the apparatus. A control unit that controls the operation of each unit according to the set operating conditions, and an electrical unit that functions as a processing unit for an image recording signal used for image formation.

  The document reading unit 2 includes an ADF (automatic document feeder) 12 and a scanner (document reader) 16 as components for reading a copied document. In the document reading unit 2, the sheet documents placed on the document tray 11 provided on the document cover 10 are automatically conveyed one by one to the reading position by the ADF 12 and discharged to the document discharge tray 13. At the reading position, a scanner 16 equipped with a reading device 15 for photoelectrically reading a document is disposed so as to face the document, so that the document can be read during ADF conveyance. When reading a book (book) or the like, the document cover 10 is rotated upward to place the document at a predetermined position on the flat bed platen 14, and the scanner 16 is moved as indicated by an arrow to perform a reading operation. I do. The configuration of the document reading unit 2 described above is the same as that of a conventional document reading device called a so-called ADF or flat bed type.

  A paper feed cassette 17 is disposed in the paper feed unit 3, and a plurality of sheets of a predetermined size are stacked on the flapper 18. A pickup roller 19 is disposed at the right end of the paper feed cassette 17. The flapper 18 is urged upward by a spring member (not shown) so that the upper surface of the stacked paper comes into pressure contact with the pickup roller 19. When the pickup roller 19 is rotationally driven in this state, the sheets are fed one by one to the sheet conveyance path by the frictional force.

  The fed paper is first conveyed to the recording unit 4 by the feed roller 20 and the press roller 21. The recording unit 4 includes a developing device 22, a paper dust removing roller 23, a corona charger 24, a photosensitive drum 25, a transfer roller 26, an exposure head 27, and a fixing roller 28 for recording on the conveyed paper. Yes. The paper dust removing roller 23 is made of a conductive sponge or the like, and captures toner or paper dust attached to the surface of the photosensitive drum 25 after transfer. The corona charger 24 uniformly charges the surface of the photosensitive drum 25 by the discharge from the corotron. The photosensitive drum 23 uniformly charged by the paper dust removing roller 23 and the corona charger 24 is exposed by an exposure head 25 in accordance with an image recording signal (in this example, a laser beam whose emission is controlled by the image recording signal). An electrostatic latent image is formed by exposing the photosensitive surface by scanning). Then, as will be described later, the toner in the developing device 22 is transferred to the electrostatic latent image formed on the photosensitive drum 25 to visualize the electrostatic latent image. The transfer roller 26 is installed at a position facing the photosensitive drum 25 with the paper interposed therebetween, and a toner image formed on the surface of the photosensitive drum 25 is transferred to the paper when a predetermined voltage is applied. The transferred toner image is sandwiched between the fixing roller 28 and the press roller 29 and heated and pressed to be fixed on the paper. The fixed paper is sandwiched between the paper discharge roller 30 and the press roller 31 and is carried out to the paper discharge tray 32. The sheet conveyance path and direction at this time are indicated by solid lines and arrows in FIG.

  In this example, a reverse conveyance path 40 is provided for duplex printing. The reverse conveyance path branches off from the paper conveyance path between the paper discharge roller 30 and the fixing roller 28, and takes the paper conveyance path and direction as indicated by the broken line and the arrow in FIG. 19 is formed so as to be merged with the sheet conveyance path between the two. In the reverse conveyance path 40, two pairs of conveyance rollers, a feed roller 43 and a press roller 44, a feed roller 45 and a press roller 46, are arranged up and down to carry the paper in the reverse conveyance path.

  When recording on both sides of a sheet, the sheet is conveyed to a sheet conveyance path indicated by a solid line in FIG. 1 and recorded on one side, and then the sheet is unloaded to a sheet discharge tray 32 by a discharge roller 30. The carry-out operation is temporarily stopped in a state where the rear end portion of the paper is sandwiched between the paper discharge roller 30 and the press roller 31. Then, the paper discharge roller 30 is driven to rotate reversely, the paper is carried into the reverse conveyance path from the rear end, and is nipped by the feed roller 43 and the press roller 44 to be conveyed in the reverse conveyance path. Next, the paper is nipped by the feed roller 45 and the press roller 46 and further conveyed, and the paper is brought into contact between the roller pair 20 and 21. When the sheet is conveyed to the sheet conveyance path in this state, the other surface is recorded to face the photosensitive drum 25, and recording is performed on both sides of the sheet.

  Next, the optional sheet feeding unit 200 according to the present invention will be described.

  The paper feeding unit 3 of the main body of the image forming apparatus performs a paper feeding operation in synchronization with the operation of the electrophotographic process during the image forming operation described above according to a command from the control unit. When the optional paper feeding unit 200 is not equipped, the paper feeding is performed exclusively from the paper feeding unit 3 provided as a standard in the image forming apparatus main body 100, but the optional paper feeding unit 200 is equipped. In this case, the optional sheet feeding unit 200 is added, the sheet cassette to be used is selected and the sheet feeding operation is controlled, and the sheet feeding operation is performed when the sheet cassette 70 on the option side is selected.

  The optional paper feeding unit 200 has a structure for stacking the image forming apparatus main body 100 described above, is provided in contact with the paper feeding unit 3 at the lower part of the main body provided as a standard, and is supplied with power supplied from the main body side. The paper feeding mechanism is operated to guide the paper from the paper feeding unit 3 on the main body side to the transport path.

  The sheet feeding mechanism of the optional sheet feeding unit 200 includes a sheet feeding cassette 70, a pickup roller 64, a feed roller 63 and a press roller 65 as conveying rollers, and a junction point of the conveying path of the main body sheet feeding unit 3 (roller pairs 20 and 21). A guide member for guiding the paper toward the upstream side of the main body is provided with the same configuration as that of the paper feeding unit 3 on the main body side.

  In addition, an input gear 60 is provided to receive power necessary for the operation of the paper feed mechanism from the main body side. The input gear 60 is a gear having a one-way clutch function, and transmits the power from the drive gear 49 on the main body side to the pickup roller 64 and the feed roller 63 via the gear trains 61 and 62. Further, the input gear 60 connects and disconnects the transmission with the drive gear 49 on the main body side by the solenoid 67 driven by the command signal so that the power supply can be disconnected and connected according to the command signal from the main body control unit. The operation of the sheet feeding mechanism can be turned on / off according to the solenoid 67 being turned on / off.

  Next, the opening / closing structure of the side cover characterizing the optional paper feeding unit according to the present invention will be described in detail.

  2 and 3 show the main part of the optional sheet feeding unit of the present embodiment. In each figure, only the optional sheet feeding unit 200 separated from the entire apparatus shown in FIG. 1 is shown as an explanatory diagram of the opening / closing operation of the side cover. FIG. 2 shows a state in which the side cover is closed, and FIG. , Showing the open state. FIG. 4 is a perspective view showing the entire optional sheet feeding unit in the opened state as in FIG.

  The side cover having a double structure will be described with reference to FIGS. 2 and 3. The double structure is configured by connecting a cover member 51 that can be opened and closed and a sheet conveying guide member 53 by a link member 52. . At one end of each of the cover member 51 and the paper transport guide member 53, the cover member 51 and the paper transport guide member 53 are pivotally attached to the machine body at points A and B shown in the drawing. Both ends of the link member 52 are connected to substantially the center in the width direction of the cover member 51 and the paper transport guide member 53, and this configuration constitutes a substantially parallel link mechanism by the cover member 51, the guide member 53, and the link member 52. Accordingly, it is possible to cause the sheet transport guide member 53 around the pivot point B to perform the same movement as the opening and closing of the cover member 51 around the pivot point A, in the closed state shown in FIG. 2 and the open state shown in FIG. The cover member and the guide member are opened and closed with the same inclination. The link member 52 is composed of a single member made of a thick plate-like body, and engaging pins project from both ends as will be described later.

  As can be seen from FIG. 2 showing the closed state, the advantage of the double structure using such parallel links is that the sheet conveyance guide member 53 can be conveyed by opening and closing the cover member 51 even when the sheet conveyance guide member 53 is separated from the cover member 51. The guide member 53 can be opened and closed. In addition, the degree of freedom in design that enables the dead space to be provided at a position where it does not occur as much as possible is increased. Even if the upper surface position of the guide member 53 is higher than the upper surface of the cover member 51 by the selection of the position performed in this way, the upper surface position of the cover member 51 is not restricted by the upper surface position of the guide member 53. Can be set in accordance with the position of the support surface of the bottom surface portion of the image forming apparatus main body 100 on which the image forming apparatus main body 100 is stacked, and the support surface of the apparatus main body can be made linear.

  Further, in this embodiment, as shown in FIGS. 3 and 4, the paper conveyance guide member 53 holds a driven press roller 65 that is paired with the feed roller 63 as a paper conveyance roller. When the conveyance path is opened, the configuration may be based on the concept that the press roller 65 is left as it is, and only the guide member 53 is opened and closed. In this example, the press roller 65 and the press roller 65 are connected from the upstream to the downstream. The conveying path is opened by adopting a method of integrally opening and closing a wide range of guide 53 members.

  In this way, the press roller 65 is held by the paper transport guide member 53, and the guide member 53 in a wide range from the upstream to the downstream of the press roller 65 is integrally opened and closed. Even when the paper is removed, it is possible to easily check the jam state and remove the paper without being obstructed by the press roller 65.

  By the way, when the cover member 51 is in the closed state, it enters a standby state in which the operation can be started when a paper feeding operation is instructed. The open / closed state of the cover member 51 can be known from the detection signal of the photo interrupter 81 that changes according to the open / closed state by detecting the sensor piece 80 attached to the cover member 51 by the photo interrupter 81 provided on the machine body side. It is used for control operations performed according to the open / close state.

  In such a paper feed standby state, the paper feed mechanism needs to be in a state where it can operate normally. In this example, the paper transport guide member 53 holds the press roller 65. Therefore, it is necessary to maintain an appropriate operating state, and for this purpose, a lock mechanism is provided.

  On the cover member 51 side, as a member constituting a lock mechanism, a lock member 55 and a lock member 55 having a locking projection 55a that contacts the locking portion 57 on the machine body and a handle portion 55b for performing an unlocking operation. Is provided with a spring 56 that biases the upper portion of the spring upward. The lock member 55 is slidable to an upper lock position or a lower release position, and the spring 56 constantly biases the lock member 55 toward the lock position.

  On the paper conveyance guide member 53 side, a hop-up spring 58 is provided as a member constituting a lock mechanism so as to act as a compression spring between the paper conveyance guide member 53 and the machine body. The hop-up springs 58 are arranged in pairs at both end portions of the paper transport guide member 53 and are set to be substantially equidistant from the lateral center position of the paper transport guide member 53. The hop-up spring 58 may be attached to the airframe side, or may be attached between the cover member 51 and the airframe.

  FIG. 5 is an enlarged plan view (FIG. 5 (a)) and an AA cross-sectional view (FIG. 5 (b)) of the attachment portion of the hop-up spring 58. A stud 59 is projected from the paper transport guide member 53, and a coil spring is used as the hop-up spring 58. The stud 59 is formed by integrally forming a substantially triangular plate-like body in a cross shape in plan view, and becomes wider toward the root portion. Therefore, when the hop-up spring 58 is inserted while being wound around the stud 59, the inner diameter portion of the hop-up spring 58 is fitted into the root portion, and when further inserted, the hop-up spring 58 is pressed against and fixed to the outer surface of the stud 59. According to this mounting method, the spring can be installed in a cantilevered manner without requiring any other mounting parts, and the stud 59 is used as a core to prevent buckling and incorrect operation. Spring operation is guaranteed.

  In the locked state (see FIG. 2), the locking projection 55a of the locking member 55 is urged to a position where it can be ejected by the spring 56 and protrude upward to come into contact with the locking portion 57 on the machine body side. On the other hand, since the paper transport guide member 53 is urged toward the cover member 51 by the hop-up spring 58, the cover member 51 is also urged through the link member 52, and the locking projection 55a locks the machine body. It is brought into pressure contact with the portion 57 and is in a stable locked state.

  When the lock is released, the handle 55b of the lock member 55 is pushed down against the urging force of the spring 56, and the protruding locking protrusion 55a is retracted. The lock state is released. By releasing the locked state, the urging force of the hop-up spring 58 against the paper transport guide member 53 acts to rotate the cover member 51 and the paper transport guide member 53 in the opening direction. Therefore, it can be easily recognized that the locked state is released, and the open state of FIG. 3 can be achieved with a slight force.

  Further, the locking projection 55a of the lock member 55 has an inclined surface and a vertical surface, and when the lock is locked, the vertical surface is a contact surface to the locking portion 57 of the fuselage, and this vertical force is applied by the urging force of the hop-up spring 58. The surface comes to work. When the cover member 51 is rotated from the open state to the locked state, if the cover member 51 is pushed in the closing direction, the inclined surface of the locking projection 55a comes into contact with the locking portion 57 of the airframe, and the locking projection. Since the portion 55a is forcibly moved downward and finally the locking portion 57 of the fuselage passes over the top of the locking projection 55a, it automatically enters a locked state. It becomes possible to be in a locked state. When the cover member 51 is rotated in the closing direction, first, the hop-up spring 58 is sandwiched between the paper transport guide member 53 and the machine body so that an urging force is applied. Therefore, the length of the hop-up spring 58 is set to such a length that the biasing force acts before the lock member 55 is locked. Therefore, the operator pushes in the cover member 51 while receiving the feeling of the urging force of the hop-up spring 58, and can raise the operator's awareness toward the locked state.

  FIG. 6 is a schematic plan view showing the connection relationship of the opening / closing mechanism when the cover member 51 is closed. In the figure, the cover member 51 and the paper transport guide member 53 have a pair of pin holding portions 51a and 53a projecting from the respective central portions, and the pin holding portion 51a has one end portion of the link member 52. Engaging pins 52b projecting laterally from both sides are pivotally supported, and the pin holding part 53a is pivotally supported by engaging pins 52a projecting laterally from both sides of the other end of the link member 52. Has been. A lock member 55 is attached to the upper portion of the pin holding portion 51 a of the cover member 51.

  A pair of bearing portions 65a are formed on the guide surface of the paper transport guide member 53, and a rod-shaped shaft body 65b is pivotally supported on the bearing portions 65a. A press roller 65 is disposed on the shaft body 65b at a position that is substantially equidistant from the lateral center of the paper conveyance guide member 53. A pair of springs 65c are mounted between the shaft body 65b and the guide surface of the paper transport guide member 53, and the shaft body 65b is urged away from the guide surface by the spring 65c. Therefore, when the press roller 65 is in contact with the feed roller 63, the two can be kept in constant pressure contact with each other. Further, the connection position of the link member 52 with respect to the paper transport guide member 53 is located in the middle of the pair of press rollers 65 and is a balanced position where a uniform pressing force can be applied to each press roller 65. Even when the number of press rollers 65 is increased, if the connecting position of the link member 52 is positioned at a balance position that applies a uniform pressing force to the respective press rollers, the pressing force of the press rollers becomes uniform, and jamming occurs. It can be prevented from occurring.

  Further, a pair of hop-up springs 58 are installed at positions that are approximately equidistant from the lateral center of the paper transport guide member 53. Therefore, since the connecting position of the link member 52 is set at an intermediate position between the pair of hop-up springs 58, the paper transport guide member 53 has the urging force of the hop-up springs 58 on both sides and the pressing force of the link member 52 in the center portion. Is balanced and kept stable.

  FIG. 7 is an enlarged schematic side view showing the respective connecting portions of the cover member 51 and the link member 52 and between the link member 52 and the paper transport guide member 53 in the closed state. FIG. 7A shows a configuration of a connecting portion between the paper conveyance guide member 53 and the link member 52. In the drawing, a long hole 53b is formed in the pin holding portion 53a of the paper conveyance guide member 53. An engagement pin 52a projecting from one end of the link member 52 is loosely fitted in the long hole 53b. Further, in the paper transport guide member 53, a portion where one end of the link member 52 is in pressure contact is formed in the thick portion 53c. As is clear from this figure, since the end portion of the link member 52 is pressed against the thick portion 53c, sufficient strength can be secured, and the engagement pin 52a is loosely fitted in the long hole 53b. Therefore, no power is applied.

  FIG. 7B shows a configuration of a connecting portion between the link member 52 and the cover member 51. In the drawing, a horizontally long notch 51b is formed in the pin holding portion 51a of the cover member 51, and the link member is formed in the notch 51b. An engaging pin 52b protruding from the other end of 52 is loosely fitted. Then, the retaining portion 55c provided hanging from the lock member 55 is overlapped with the notch 51b to prevent the engagement pin 52b from being detached from the notch 51b. And since the other edge part of the link member 52 press-contacts to the inner surface of the cover member 51, sufficient intensity | strength can be ensured and force is not added to the engagement pin 52b. If a wide flange portion is formed around the link member 52, the strength of the link member 52 can be further increased, and the pressing force can be dispersed on the surface of the flange portion even in the case of pressure contact.

  Then, it is attached to the paper feed unit main body so that the hinge position (pivot fulcrum A) that is the rotation center of the paper transport guide member 53 is higher than the hinge position (pivot fulcrum B) that is the rotation center of the cover member 51. It has been. By setting the positional relationship as described above, as shown in FIG. 3, the sheet conveyance guide member 53 can be set to be opened in the horizontal direction while the link member 52 is inclined in the opened state. Thus, the sheet conveyance guide member 53 can be opened greatly. FIG. 8 shows an enlarged schematic side view of the connecting portion of each member in the opened state. However, as shown in FIG. 8A, the engaging pin 52a of the link member 52 is opened in the opened state. Is slid to the lowermost part in the long hole 53b of the paper conveyance guide member 53, and it is avoided that the end of the link member 52 slides on the paper conveyance guide member 53 and obstructs the opening operation. As shown in FIG. 8B, since the engaging pin 52b of the link member 52 can also slide to the lowermost portion of the notch 51b of the cover member 51, the degree of freedom of the link member 52 is increased and its movement is restricted. The operability of the opening / closing operation is improved. Both end portions of the link member 52 are formed in a circular shape so as not to hinder the movement at the connecting portion.

  In the above, as an embodiment of the present invention, the recording unit 4 uses a laser printer system and an embodiment related to an image forming apparatus having a copying function is illustrated. However, the present invention is not limited to drawing data generated based on image data. Therefore, the present invention can be widely used in image forming apparatuses that perform printing on paper as a recording medium. That is, it may be a single function machine having only a printer function, or may be applied to an image processing apparatus combined with a facsimile function or another image processing function.

1 is a schematic view of an entire image forming apparatus including an embodiment according to the present invention. It is a figure which shows the principal part of the state which closed the side cover. It is a figure which shows the principal part of a state which opened the side cover. It is a perspective view regarding embodiment of the state which opened the side cover. It is the top view and sectional drawing regarding the attachment structure of a hop-up spring. It is a schematic plan view regarding the principal part of the state which closed the side cover. It is a figure regarding the connection part of the state which closed the side cover. It is a figure regarding the connection part of the state which opened the side cover.

Explanation of symbols

100 Image Forming Apparatus Main Body 2 Document Reading Unit 3 Paper Feeding Unit 4 Recording Unit 200 Optional Paper Feeding Unit 51 Cover Member 52 Link Member 53 Paper Transport Guide Member 58 Hop-Up Spring 59 Stud

Claims (6)

  A recording paper feed unit having a structure for loading an image forming apparatus main body and capable of optional equipment, and a paper transport guide unit that is set to a paper transport state or a paper transport path open state by an opening / closing operation, and a paper transport And a resilient member that biases the guide portion in a direction to open the guide portion when the guide portion is closed.   A side cover that can be opened and closed is provided, and the paper transport guide unit is set in a paper transport state when the cover is closed or a paper transport path is opened when the cover is open in conjunction with the side cover. Item 1. Paper feed unit.   3. The paper feeding unit according to claim 2, wherein the side cover and the paper transport guide portion are linked together by a link.   The paper feeding unit according to any one of claims 1 to 3, wherein the paper transport guide section includes a press roller used for paper transport and a guide section provided downstream thereof.   The sheet feeding unit according to any one of claims 1 to 4, wherein the elastic member is disposed at both end portions of the sheet conveyance guide unit.   6. The paper feed unit according to claim 1, wherein the elastic member is a coil spring wound around a stud projecting from the paper transport guide portion.

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