JP5522089B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a fall prevention mechanism in which a transfer belt unit can be safely and easily attached to and detached from a main body of an image forming apparatus.

  Conventionally, an image forming apparatus that forms a toner image on an image carrier using an electrophotographic method using toner, transfers the toner image onto a sheet, and fixes the transferred toner image on the sheet with a fixing device. It has been known.

  Such an image forming apparatus includes, for example, a plurality of internal devices such as a transfer belt unit, an image forming unit, and a fixing unit in a detachable manner. During maintenance work of these internal devices, the internal device is removed from the mounting portion of the image forming apparatus main body, removed, repaired or replaced with a new one, and remounted on the mounting portion.

  At that time, since many internal devices are heavy, when removing and removing the internal device from the mounting part, it is necessary to release the lock after surely releasing it. There is a possibility that the internal device may be damaged by forming an abnormal engagement portion with the internal device such as a catch.

  In order to prevent such a problem, for example, a configuration has been proposed in which when the fixing unit is taken out of the apparatus main body, the cradle on which the fixing unit is placed and pulled out is inclined so that it can be easily taken out ( For example, see Patent Document 1).

  In addition, the development unit of the tandem color image forming apparatus includes a variable capacity reserve tank in addition to the toner cartridge, and the toner cartridge can be replaced after the toner in the toner cartridge is completely used up. An image forming apparatus capable of exchanging a toner cartridge even during printing has been proposed (see, for example, Patent Document 2).

  Further, as described above, various internal units are disposed in the image forming apparatus. Among them, the transfer belt unit is not only heavy but also the largest in size. Accordingly, when the transfer belt unit is removed from the mounting portion and taken out, it must be handled with great care.

  As such a transfer belt unit, there is one described for a primary transfer belt unit that is detachably attached from an image forming apparatus. (For example, refer to Patent Document 3.)

JP 2005-266157 A JP 2008-276034 A JP 2007-094251 A

  However, although the technique of Patent Document 3 says that the primary transfer belt unit is detachably attached to the image forming apparatus, the main focus is on downsizing the primary transfer belt unit.

  In general, the transfer belt unit is the largest unit in terms of dimensions as described above, and therefore, careful handling is required for its handling. When the transfer belt unit is taken out, both end portions in the longitudinal direction of the belt cannot be held by hand because they are portions spanned between the driving roller and the driven roller.

  In other words, since the transfer belt unit has only a portion of the belt frame that is held in the belt width direction by hand, handling is very unstable when the transfer belt unit is taken out from the image forming apparatus main body. Specifically, the front portion of the belt frame can be held in the hand, but the rear portion cannot be held in the hand until just before being pulled out.

  Therefore, there is often a problem that the rear portion of the belt frame falls off the guide rail before falling in the hand. However, Patent Document 3 does not describe a specific method for attaching and detaching the primary transfer belt unit.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems, and to provide an image forming apparatus including a fall prevention mechanism in which a transfer belt unit can be safely and easily attached to and detached from an image forming apparatus main body. To do.

  In order to solve the above-described problems, the image forming apparatus according to the present invention, when maintaining the internal unit, opens the internal protection opening / closing member and slides both side ends of the internal unit on the guide / support rail. In the image forming apparatus configured to pull out the internal unit to the outside, one end is connected by a hinge to the outer end portion of the guide / support rail, and the other end faces upward when the opening / closing member is closed. A first rod-like member standing upright, and a second rod-like member having an upper end connected to the other end of the first rod-like member by a hinge and a lower end connected to the side of the opening / closing member by a hinge And when the opening and closing member is opened, the first rod-shaped member falls horizontally in the extending direction of the guide / support rail to form an extension portion of the guide / support rail, The second rod-shaped member is End while being supported on the side near the opening and closing member, the other end supporting as the front end when lying horizontally in the first rod-like member at the upper end, as configured.

  According to the present invention, it is possible to provide an image forming apparatus including a transfer belt unit configured to be detachable from the apparatus main body safely and easily.

1 is a cross-sectional view illustrating an internal configuration of a full-color image forming apparatus (printer) according to Embodiment 1 of the invention. (a) is an external perspective view of the printer according to the first embodiment, and (b) is a schematic diagram together with a transfer belt, picking up only one of the developing device of the image forming unit and the reserve tank and the toner cartridge of the toner supply unit in an easy-to-understand manner. FIG. (a), (b) is a figure which shows the structure before attaching the fall prevention mechanism at the time of taking out the transfer belt unit of the printer which concerns on Example 1. FIG. (a), (b) is the figure which shows the fall prevention mechanism at the time of taking out the transfer belt unit of the printer which concerns on Example 1, and its operation state, (c) is the elements on larger scale of (b). FIG. 5A is an overall view in the state of FIG. 4C, and FIG. 5B is a view showing a state in which the transfer belt unit is taken out using a fall prevention mechanism.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, a two-component developer including a toner and a carrier is used. In the following description, the two-component developer is simply referred to as a developer or a toner.

  FIG. 1 is a cross-sectional view illustrating an internal configuration of a full-color image forming apparatus (hereinafter simply referred to as a printer) according to Embodiment 1 of the present invention.

  A printer 1 shown in FIG. 1 is an electrophotographic secondary transfer tandem color image forming apparatus, and includes an image forming unit 2, a transfer belt unit 3, a toner supply unit 4, a paper feeding unit 5, and a belt type fixing device. It comprises a unit 6 and a transport unit 7 for duplex printing.

  The image forming unit 2 is in contact with the lower running unit surface 8a of the transfer belt 8 of the transfer belt unit 3 and multi-stages four developing devices 9 (9k, 9c, 9m, 9y) from right to left in FIG. It consists of a side-by-side configuration. The image forming unit 2 is held by a frame of the printer 1 main body so as to be movable up and down from a printing execution position shown in FIG. 1 to a maintenance position below it.

  Of the four developing devices 9, three developing devices 9c, 9m, and 9y on the upstream side (the left side in the figure) are cyan (C), magenta (M), and yellow (Y), which are subtractive three primary colors, respectively. A mono-color image is formed with the color toner, and the developing device 9k forms a monochrome image mainly with black (K) toner used for characters and dark portions of the image.

  Each of the developing devices 9 has the same configuration except for the color of the toner that develops the image. Therefore, the configuration of the developing device 9y for yellow (Y) toner will be described below as an example.

  The developing device 9 includes a photosensitive drum 10 at the top. The photosensitive drum 10 has a peripheral surface made of, for example, an organic photoconductive material. A cleaner 11, a charging roller 12, an optical writing head 13, and a developing roller 15 of the developing device 14 are disposed around the periphery of the photosensitive drum 10.

  The developing device 14 includes a housing 16 that covers the outside, a partition wall 17 provided inside, a developing roller 15, a first stirring and conveying screw 18, and a second stirring and conveying screw 19. Although not specifically shown, the first and second agitating and conveying screws 18 and 19 include a screw shaft and a fin that is integrally formed with the screw shaft and rotates.

  The developing unit 14 includes a reserve tank 27 (27k, 27c, 27m, 27y) of the toner supply unit 4, and black (K) and cyan (C) as indicated by K, C, M, and Y in FIG. , Magenta (M) or yellow (Y) toner is supplied.

  The transfer belt unit 3 has an endless transfer belt 8 that extends in the shape of a flat loop in the left-right direction in the figure at approximately the center of the main unit, and the transfer belt 8 is stretched over the transfer belt 8. A driving roller 21 and a driven roller 22 are provided to circulate and move counterclockwise as indicated by an arrow a in the figure.

  The transfer belt 8 includes a primary transfer roller 20 that is integrated with the unit. The primary transfer roller 20 is pressed against the photosensitive drum 10 via the transfer belt 8 and directly transfers (primary transfer) the toner image to the belt surface that circulates below. The transfer belt 8 conveys the toner image to the secondary transfer unit 23 to the paper for further transfer (secondary transfer) to the paper.

  A belt cleaner 24 is disposed on the transfer belt 8. The belt cleaner 24 includes a cleaning blade 25 that comes into contact with the surface of the transfer belt 8 that is stretched over the drive roller 21. A waste toner collecting container 26 is detachably disposed below the belt cleaner 24.

  The belt cleaner 24 scrapes and removes the waste toner remaining on the surface of the transfer belt 8 by the cleaning blade 25, and sends the waste toner to the waste toner collection container 26 below by a conveying screw.

  The toner supply unit 4 includes four reserve tanks 27 (27k, 27c, 27m, and 27y) that are disposed above the upper running unit of the transfer belt 8 and are detachably disposed on the reserve tanks 27, respectively. Toner cartridge 28 (28k, 28c, 28m, 28y) for toner replenishment.

  The four toner cartridges 28k, 28c, 28m, and 28y accommodate black (K), cyan (C), magenta (M), and yellow (Y) toners, respectively, and four reserve tanks 27 (27k, 27c). , 27m, 27y) are replenished with toner from the toner cartridge 28 mounted thereon.

  These four reserve tanks 27 are hidden behind the opposite side of the transfer belt unit 3 in FIG. 1, but are connected to the corresponding developing devices 14 of the developing device 9 by toner supply paths.

  Although not particularly shown, the toner supply unit 4 is held on the frame of the printer 1 main body so as to be able to be raised and lowered from the printing execution position shown in FIG. 1 to a maintenance position above it.

  Two electrical parts 30 are disposed on the left side of the toner supply unit 4 from the left side of the belt cleaner 24 to above the drive roller 21. The electrical unit 30 includes a circuit board on which a control device including a plurality of electronic components is mounted.

  The paper feed unit 5 includes two paper feed cassettes 29 (29a, 29b) arranged in two upper and lower stages. A paper take-out roller 31, a feed roller 32, a separating roller 33, and a standby conveyance roller pair 34 are disposed in the vicinity of the paper feed opening (right side of the drawing) of the two paper feed cassettes 29, respectively.

  A secondary transfer roller 35 that is in pressure contact with the driven roller 22 via the transfer belt 8 is disposed in the paper transport direction (vertically upward in the drawing) of the standby transport roller pair 34, and the secondary transfer onto the paper described above. Part 23 is formed.

  A belt-type heat fixing unit 6 is disposed downstream (upward in the drawing) of the secondary transfer portion. On the further downstream side of the belt-type heat fixing unit 6, a pair of carry-out rollers 36 for carrying out the fixed paper from the belt-type heat fixing unit 6, and a paper discharge tray 37 formed on the upper surface of the apparatus. A paper discharge roller pair 38 for paper discharge is provided.

  The conveyance unit 7 for double-sided printing also serves as an opening / closing member whose outer surface (right outer surface in the drawing) opens or shields the inside of the printer 1 from the side surface to the outside.

  This duplex printing transport unit 7 has a start return path 39a that branches rightward in the figure from just before the paper discharge roller pair 38, an intermediate return path 39b that bends downward, and a left lateral direction opposite to the above. Thus, a return path 39 including a terminal return path 39c for finally inverting the return sheet is provided.

  In the middle of the return path 39, five pairs of return rollers 41 (41a, 41b, 41c, 41d, 41e) are arranged. The exit of the end return path 39 c joins the conveyance path to the pair of standby conveyance rollers 34 corresponding to the sheet feeding cassette 29 b below the sheet feeding unit 5.

  2A is an external perspective view of the printer 1, and FIG. 2B is a developing device 9 of the image forming unit 2 and a reserve tank 27 and a toner cartridge 28 of the toner supply unit 4 in an easy-to-understand manner. FIG. 6 is a perspective view schematically showing only the transfer belt 8 together. 2A and 2B, the same components as those in FIG. 1 are given the same reference numerals as those in FIG.

  As shown in FIG. 2 (a), the printer 1 is provided with a front door 42 at the front, and an opening / closing member 44 with a handle 43 at the top on the right side. The double-sided printing conveyance unit 7 shown in FIG.

  As shown in FIG. 1, the printer 1 does not directly transfer a toner image onto a sheet. Instead, the printer 1 conveys a sheet conveyed vertically to a secondary transfer unit by a pair of standby conveying rollers 34 via a transfer belt 8. The toner image is transferred.

  Accordingly, troubles such as paper jams do not occur in the arrangement portion of the kits, so the operation of attaching / detaching consumables such as kits concentrated on the left side of FIG. 1 opens the front door 42 shown in FIG. The kits are configured to be exchanged in the longitudinal direction (front door direction).

  Similarly, the printer 1 transfers the toner image to a sheet conveyed in the vertical direction to the secondary transfer unit via the transfer belt 8, and further conveys the sheet in the vertical direction to fix the transferred toner image on the sheet. It is a method to do.

  Therefore, at the time of maintenance processing for recovering from a problem such as a paper jam occurring in the paper transport path, as shown in FIG. 2 (a), it is possible to cope with it simply by opening the right opening / closing member 44.

  The toner cartridge 28 shown in FIG. 2 (b) is attached to and detached from the reserve tank 27 in the front direction with respect to the printer 1 main body shown in FIG. 2 (a), that is, as shown by the double arrow b in FIG. 2 (b). It is free. Similarly, the transfer belt unit 3 is also detachable from the printer 1 body in the front direction.

  Although it is not visible between the toner cartridge 28 and the reserve tank 27 in FIG. 2B, when the toner cartridge 28 is attached to the reserve tank 27, it communicates with the reserve tank 27 and becomes reserved. A toner replenishing port for replenishing toner is formed.

  A cartridge motor 45 is externally engaged with the screw shaft of the toner cartridge 28, and a reserve tank motor 46 is externally engaged with the screw shaft of the reserve tank 27. A toner replenishing mechanism including a screw shaft and fins of the toner cartridge 28 conveys the internal toner to the toner replenishing port.

  The toner replenishing mechanism comprising the screw shaft and fins of the reserve tank 27 conveys the toner replenished from the toner cartridge 28 through the toner replenishing port to the upper end opening of the toner replenishment path 47 connecting the reserve tank 27 and the developing device 14. To do. The toner replenishment path 47 is disposed so as to wrap around the back of the transfer belt unit 3 and is connected to the developing device 14.

  FIGS. 3A and 3B are diagrams showing a structure before the fall prevention mechanism is attached for comparison with the configuration after the fall prevention mechanism is attached when the transfer belt unit of the printer according to the first embodiment is taken out. is there. In FIGS. 3A and 3B, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  As shown in FIG. 3A, when the front door 42 is opened from the image forming apparatus main body 40 (hereinafter simply referred to as the apparatus main body 40), the front door 42 is horizontally opened and fixed in position. Above the transfer belt unit 3, four toner cartridges 28k, 28c, 28m, and 28y are replaceably disposed, and a belt-type fixing unit 6 is disposed on the right side thereof.

  Below the transfer belt unit 3, the four developing devices 9k, 9c, 9m, and 9y are arranged so that they can be removed during maintenance. A handle 48 is formed at the front of the frame of the transfer belt unit 3.

  FIG. 3B shows a state in which the handle 48 of the transfer belt unit 3 is put on the hand, both end portions on the lower surface of the transfer belt unit 3 are brought into sliding contact with the guide / support rail 49 and pulled forward. Although there is a handle at the rear end of the transfer belt unit 3, the transfer belt unit 3 cannot be held in the hand unless the hand is inserted through a slight gap after the transfer belt unit 3 is pulled out to the very front of the main unit.

  In this state, the handling of the transfer belt unit 3 is extremely unstable, and the rear end part often comes off the guide / support rail 49 and falls to the rear of the front door 42, and the hinge of the front door 42 or the transfer The belt unit 3 itself is damaged.

  4A and 4B are diagrams showing a fall prevention mechanism and its operating state when the transfer belt unit 3 of the printer 1 according to the first embodiment is taken out, and FIG. 4C is an enlarged perspective view of FIG. is there. 4 (a), (b), and (c), the same components as in FIGS. 3 (a) and (b) are assigned the same numbers as in FIGS. 3 (a) and (b). It shows.

  As shown in FIG. 4 (a), in the fall prevention mechanism of this example, first, when the front door 42 as an internal protection opening / closing member is closed, the outer end of the guide / support rail 49 is hinged by the hinge 51. A first rod-like member 52 is provided that is connected at one end and stands upright with the other end facing upward.

  The other end of the first bar-like member 52 is provided with a second bar-like member 55 having an upper end connected by a hinge 53 and a lower end connected by a hinge 54 near the side of the front door 42.

  In FIG. 4 (a), the guide / support rail 49 and the hinges and rod-like members connected thereto are shown by solid lines, but in reality, they are located inside the apparatus main body 40 and the front door 42. Invisible to the eyes. Therefore, it should be shown transparently with a virtual line, but is shown with a solid line because it is difficult to understand.

  In this configuration, as shown in FIG. 4 (b), when the front door 42 is opened horizontally as in FIGS. 3 (a) and 3 (b), the first bar-shaped member 52 is guided and supported. The guide 49 and the support rail 49 are extended to fall horizontally in the extension direction of the rail 49.

  And the 2nd rod-shaped member 55 supports the other end used as the front-end part when the 1st rod-shaped member 52 is falling horizontally by the upper end while being supported by the side part vicinity of the front door 42 at the lower end. The aspect is changed as follows.

  In the partially enlarged perspective view of FIG. 4C, the transfer belt unit 3 is not shown in order to clearly show the connection state between the guide / support rail 49 and the first rod-like member 52.

  FIG. 5A shows a partial perspective view of FIG. 4C as an overall perspective view. FIG. 5A also omits the illustration of the transfer belt unit 3 in order to clearly show the connection state between the guide / support rail 49 and the first rod-shaped member 52. FIG. 5B is a diagram showing a state in which the transfer belt unit 3 is pulled out.

  As described above, when maintaining the transfer belt unit 3 as an internal unit, the front door 42 as an opening / closing member is opened, and both end portions of the transfer belt unit 3 are slidably brought into contact with the guide / support rail 49, thereby transferring the transfer belt. Pull out the unit 3 to the outside.

  With this configuration of the fall prevention mechanism, even if the rear end portion of the transfer belt unit 3 is exposed to the outside, both side end portions of the unit are placed on the first rod-like member 52 as an extension portion of the guide and support rail 49. The rear end portion of the transfer belt unit 3 does not fall.

  Accordingly, the transfer belt unit 3 can be sufficiently pulled out by grasping the handle 48, and the handle at the rear end portion of the transfer belt unit 3 can be grasped with a margin, so that the transfer belt to the printer 1 main body can be obtained. The unit 3 can be attached and detached safely and easily.

As mentioned above, although embodiment of this invention was described, this invention is contained in the invention described in the claim, and its equal range. Hereinafter, the invention described in the scope of claims of the present application will be appended.
[Appendix 1]

In maintenance of the internal unit, in the image forming apparatus configured to open the opening / closing member for internal protection and pull out the internal unit to the outside while sliding the both side ends of the internal unit to the support rail,
A first rod-like member standing upright with the other end facing upward when one end is connected to the outer end of the support rail by a hinge and the opening / closing member is closed;
A second rod-shaped member having an upper end coupled to the other end of the first rod-shaped member by a hinge and a lower end coupled to the vicinity of the side of the opening / closing member by a hinge;
Have
When the opening and closing member is opened,
The first rod-shaped member falls horizontally in the extension direction of the support rail to form an extension portion of the support rail,
The second rod-shaped member has the lower end supported near the side of the opening / closing member and the other end serving as a front end portion when the first rod-shaped member is tilted horizontally at the upper end. To support,
An image forming apparatus.
[Appendix 2]

  The image forming apparatus according to claim 1, wherein the opening / closing member is a front door, and the internal unit is a transfer belt unit.

  The present invention can be used in an image forming apparatus including a fall prevention mechanism in which a transfer belt unit can be safely and easily attached to and detached from the image forming apparatus main body.

1 Full-color image forming device (printer)
2 Image forming unit 3 Transfer belt unit 4 Toner supply unit 5 Paper feeding unit 6 Belt fixing unit 7 Double-sided printing transport unit 8 Transfer belt 8a Lower running unit surface 9 (9m, 9c, 9y, 9k) Developing devices 9r, 9r -1, 9r-2 Preliminary developing device for special toner 10 Photosensitive drum 11 Cleaner 12 Charging roller 13 Optical writing head 14 Developer 15 Developing roller 16 Housing 17 Partition 15 Developing roller 18 First stirring and conveying screw 19 Second Agitating and conveying screw 20 primary transfer roller 21 driving roller 22 driven roller 23 secondary transfer unit 24 belt cleaner 25 cleaning blade 26 waste toner collection container 27 (27m, 27c, 27y, 27k) reserve tank 28 (28m, 28c, 28y, 28k) Toner cartridge 29 (29a, 9b) Paper feed cassette 30 Electrical section 31 Paper take-out roller 32 Feed roller 33 Rolling roller 34 Standby transport roller pair 35 Secondary transfer roller 36 Unload roller pair 37 Paper discharge tray 38 Paper discharge roller pair 39 Return path 39a Start return path 39b Intermediate return path 39c End return path 40 Image forming apparatus main body (apparatus main body)
41 (41a, 41b, 41c, 41d, 41e) Return roller pair 42 Front door 43 Handle 44 Opening / closing member 45 Cartridge motor 46 Reserve tank motor 47 Toner supply path 48 Handle 49 Guide and support rail

Claims (2)

In an image forming apparatus configured to pull out the internal unit to the outside while opening an opening / closing member for internal protection and bringing both end portions of the internal unit into sliding contact with a guide / support rail when maintaining the internal unit ,
A first rod-shaped member that is connected to an outer end portion of the guide and support rail with a hinge, and when the opening and closing member is closed, a first rod-like member that stands up toward the other end;
A second rod-shaped member having an upper end coupled to the other end of the first rod-shaped member by a hinge and a lower end coupled to the vicinity of the side of the opening / closing member by a hinge;
Have
When the opening and closing member is opened,
The first rod-shaped member falls horizontally in the extending direction of the guide / support rail to form an extension of the guide / support rail,
The second rod-shaped member has the lower end supported near the side of the opening / closing member and the other end serving as a front end portion when the first rod-shaped member is tilted horizontally at the upper end. To support,
An image forming apparatus.   The image forming apparatus according to claim 1, wherein the opening / closing member is a front door, and the internal unit is a transfer belt unit.