JP2008058892A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus which is prevented from being damaged in a double-sided conveying part, which enables a user to perform the disposal of jammed paper with easy operation and of which the installation space is not increased. <P>SOLUTION: A double-sided guide plate 22 on a side adjacent to a paper supply cassette 7 out of the double-sided guide plates 21 and 22 constituting a double-sided conveying path 30 is provided to rock centering around a fulcrum 23. When pulling out the paper supply cassette 7 leftward in figure, the guide plate 22 is turned to open the double-sided conveying path 30, and when the paper supply cassette 7 is inserted, the guide plate 22 is pushed up to close the double-sided conveying path 30. In such a state that the cassette is set, a guide plate pressing part 31 holds the guide plate 22 at a closing position. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly to an image forming apparatus capable of forming images on both sides of a sheet-like recording medium.

JP 2001-222139 A JP 2005-315920 A JP 2002-265091 A

  Image forming apparatuses such as copiers and printers that can form images on both sides of a sheet-like recording medium (hereinafter referred to as paper) are well known. There are various formats for recording images on both sides of the paper. As a typical example, paper with an image recorded on one side is reversed by the paper reversing unit, and the paper is called a double-sided conveyance path. There is a method of conveying the image again to the image forming unit via a path (sheet conveyance path). And the structure by which the double-sided conveyance path is provided along sheet | seat storage means, such as a paper feed cassette or a paper feed tray, is employ | adopted widely, for example, it is disclosed by the said patent documents 1-3.

  In such an image forming apparatus capable of double-sided recording, when the machine stops due to paper jam or the like, the paper being conveyed may remain inside the apparatus. As a method for removing the recording paper remaining inside, as disclosed in Patent Document 1, a double-sided conveyance path is provided so as to be able to be pulled out in the recording paper conveyance direction, and a conveyance path forming member (hereinafter referred to as a double-sided conveyance path) is drawn out. Some of them process recording paper by opening a double-sided guide plate. However, in such a configuration, a holding member for holding the double-sided conveyance path so that it can be pulled out is necessary, or a large space for drawing out is required in front of the apparatus. Space was increasing.

  Therefore, a re-conveying path (re-feeding path after reversing the front and back of the paper) is provided above the paper feeding cassette, and the double-sided guide plate is placed on the paper feeding cassette side using the space where the paper feeding cassette is pulled out. A method of handling jammed paper by turning (downward) was considered. However, this method causes damage to the apparatus when the paper cassette is inserted without forgetting to close the double-sided guide plate. As a measure for preventing this, as disclosed in Patent Document 2, it is proposed that the double-sided guide plate is urged upward by an elastic member, and a lock member is provided at the end on the rotating side. In addition, as disclosed in Patent Document 3, it has also been proposed that a handle of a lock member is provided so as to be rotatable so as not to come into contact with a paper feed tray.

  However, in the inventions disclosed in Patent Documents 2 and 3, a lock member is required to hold the double-sided guide plate, and the operator of the apparatus can forget to release the lock member and remove the recording paper in the apparatus. There is a problem that the mechanism of the lock member is not complicated and the device configuration is complicated.

  In addition, when there is a conveyance roller driving side below the double-sided guide plate, in order to be able to release the double-sided guide plate, it is necessary to use a complicated structure such as an idler gear to transfer the conveyance roller drive. is there.

  The object of the present invention is to solve the above-mentioned problems in the prior art, to prevent damage to the apparatus in the double-sided conveyance unit, to handle jammed paper with a simple operation, and without increasing the installation space. An object is to provide an image forming apparatus.

  According to the present invention, the object is to re-create a sheet storage means that is detachable from the apparatus body, a sheet reversing unit that reverses the front and back of a sheet on which an image is recorded, and a sheet that is reversed by the sheet reversing unit. An image forming apparatus having a refeed path for transporting to an image unit, wherein at least a part of the refeed path is provided as a double-sided transport path along the sheet storage unit. Of the conveyance path forming members constituting the conveyance path, a formation member adjacent to the sheet storage means moves to a first position where the double-side conveyance path is opened and a second position where the double-side conveyance path is closed. This is solved by moving the adjacent forming member to the first position and the second position by detaching the sheet storage means.

  In addition, it is preferable that a holding portion that holds the adjacent forming member at the second position is provided in the sheet storage unit when the sheet storage unit is mounted on the apparatus main body.

Further, it is preferable that the adjacent forming members are provided so as to be able to swing around the upstream end portion in the sheet conveying direction.
In addition, a holding portion that holds the adjacent forming member in the second position in the vicinity of the end of the forming member opposite to the fulcrum when the sheet storage unit is mounted on the apparatus main body is provided in the sheet storage unit. Preferably.

Preferably, the holding portion is provided with an elastic member, and the elastic member urges the adjacent forming member in the second position direction.
Further, it is preferable that the holding portion is provided outside the sheet passing area.

Further, it is preferable that the holding portions are provided on both sides in the sheet width direction orthogonal to the sheet feeding direction.
In addition, it is preferable that a guide portion that contacts the adjacent forming member and guides the movement of the adjacent forming member is provided on the front side in the insertion direction of the sheet storage unit.

  Further, it is preferable that friction reducing means for reducing sliding friction is provided at a sliding contact portion where the sheet storing means and the adjacent forming member are in sliding contact when the sheet storing means is detached.

The friction reducing means is preferably a sliding roller.
The friction reducing means is preferably a low friction member.
In addition, a pair of conveyance rollers is disposed on the double-sided conveyance path, and a driving side roller of the conveyance roller pair is supported by the adjacent forming member, and the adjacent forming member swings around the axis of the driving side roller as a fulcrum. It is preferable to be provided so as to be movable.

  According to the image forming apparatus of the present invention, the adjacent forming members move to the first position where the double-sided conveyance path is opened and the second position where the double-sided conveyance path is closed as the sheet storage unit is detached. Jam processing on the conveyance path can be easily performed. Further, without forgetting to close the double-sided conveyance path after the jam processing, it is possible to prevent damage to each part of the apparatus and inoperability of the apparatus.

  According to the configuration of the second aspect, it is not necessary to provide a lock mechanism for locking the conveyance path forming member in the closed position, and it is possible to prevent damage to the apparatus due to the operator forgetting to release the lock mechanism.

With the configuration of the third aspect, the configuration in which the adjacent forming members are moved to the first position and the second position can be realized with a simple configuration.
According to the configuration of the fourth aspect, by holding the adjacent forming member in the vicinity of the end opposite to the swing fulcrum, the forming member can be reliably held and the conveyance accuracy can be reliably maintained. .

  According to the fifth aspect of the present invention, since the adjacent forming member is urged in the second position direction by the elastic member provided in the holding portion, the forming member can be reliably held. Moreover, the impact at the time of sheet | seat storage means mounting | wearing can be relieve | moderated with an elastic member.

According to the configuration of the sixth aspect, since the holding unit is provided outside the sheet passing area, the holding unit can be set without being affected by the sheet stacking amount.
With the configuration of the seventh aspect, since the holding portions are provided on both sides in the sheet width direction orthogonal to the sheet feeding direction, it is possible to reliably hold the adjacent forming members from both sides.

  According to the configuration of the eighth aspect, the movement of the adjacent forming member can be guided by the guide portion provided on the front side in the insertion direction of the sheet storing means, and the forming member can be smoothly moved.

According to the ninth aspect of the present invention, it is possible to reduce the sliding friction between the sheet storage means and the adjacent forming member when the sheet storage means is detached.
With the structure of the tenth aspect, the sliding friction can be effectively reduced by the sliding roller.

With the structure of the eleventh aspect, the sliding friction can be reduced with a simple structure by the low friction member.
With the configuration of the twelfth aspect, even when the driving side roller is supported by the adjacent forming member, the adjacent forming member can be moved without complicating the configuration of the drive system. Moreover, a mechanism for driving delivery is not necessary, and it is possible to avoid complication and enlargement of the configuration.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional configuration diagram showing an outline of a printer which is an example of an image forming apparatus according to the present invention. In the printer 100 shown in this figure, a photosensitive drum 1 as an image carrier is disposed at substantially the center of the apparatus main body. The photosensitive drum 1 is driven to rotate counterclockwise in the figure by a driving means (not shown). Around the photosensitive drum 1, devices such as a charging roller 2, a developing device 3, and a transfer roller 4 are disposed. A fixing device 5 is arranged on the right side of the photosensitive drum 1 in the drawing. An optical writing device 6 is disposed at an upper position in the apparatus main body, and a paper feed cassette 7 for accommodating a recording medium P such as transfer paper is disposed at a lower position. The paper feed cassette 7 can be pulled out in the left direction in the figure.

  Further, on the right side of the fixing device 5 in the drawing, a paper reversing unit 10 for reversing the paper after fixing is provided. In the sheet reversing unit 10, a switchback conveyance path 15 and a refeed conveyance path 16 are formed by a guide plate or the like, and conveyance roller pairs 11 to 14 are appropriately disposed in the sheet conveyance path. A switching claw 17 for switching the paper transport direction is provided at the entrance portion from the fixing device 5 to the paper reversing unit 10.

An image forming operation of the printer 100 configured as described above will be briefly described.
The image forming apparatus of this example is a so-called printer, and a signal for writing is sent from an external device such as a computer. The optical writing device 6 is driven based on the received image signal, and light from a laser light source (not shown) is scanned by a polygon mirror that is rotationally driven by a motor, and is uniformly charged by the charging roller 2 through the mirror and the like. The photosensitive drum 1 is irradiated to form an electrostatic latent image on the photosensitive member 1. The electrostatic latent image formed on the photosensitive drum 1 is developed by the developing device 3 and visualized as a toner image.

  On the other hand, transfer paper, for example, is fed as a recording medium from the paper feed cassette 7 by the paper feed roller 8 and conveyed to the registration roller 9. Then, taking the timing with the toner image formed on the photosensitive drum 1, the transfer paper is sent out by the registration roller 9, and the toner image on the photosensitive drum 1 is transferred onto the transfer paper by the action of the transfer roller 4. The The transfer paper on which the unfixed toner is transferred is conveyed to the fixing device 5 and the toner image is fixed on the transfer paper by heat and pressure. The transfer paper on which the toner image is fixed is discharged by a paper discharge roller 18 to a paper discharge tray 19 on the upper surface of the apparatus. At this time, the switching claw 17 at the entrance of the sheet reversing unit 10 is in a position indicated by a solid line.

  When performing double-sided printing, the switching claw 17 is switched to the position indicated by the phantom line in the drawing, and a transfer sheet having a toner image fixed on one side of the sheet is sent to the sheet reversing unit 10. The transfer sheet that has entered the sheet reversing unit 10 is first fed into the switchback conveyance path 15 by the conveyance roller 11. When the sensor 20 detects the trailing edge of the transfer paper, the switching claw 17 is switched to the position indicated by the solid line in the figure, and the conveying roller 11 is reversed. As a result, the transfer paper is fed to the refeed path 16, and the transfer paper is re-fed to the registration roller 9 by the transport rollers 12 to 14, thereby reversing the front and back of the transfer paper. Then, the toner image is transferred from the photosensitive drum 1 to the re-fed transfer paper, and the transfer paper on which the toner image is fixed by the fixing device 5 is discharged to the paper discharge tray 19 to complete double-sided printing. .

  By the way, a substantially horizontal portion along the upper portion of the sheet feeding cassette 7 in the refeeding path 16 is configured as a double-sided conveyance path 30 guided by the double-sided guide plates 21 and 22. The lower double-sided guide plate 22 is a forming member adjacent to the paper feed cassette 7 among the transport path forming members constituting the double-sided transport path 30.

  The double-sided guide plates 21 and 22 support a driving roller and a driven roller constituting the conveying roller pair 13 and 14, respectively. That is, as shown in FIG. 2, among the rollers constituting the transport rollers 13 and 14, the driving rollers 13a and 14a are mounted and supported on the upper double-sided guide plate 21, and the driven rollers 13b and 14b are lower-side double-sided guide plates. 22 is supported. Further, the lower double-sided guide plate 22 is provided so as to be rotatable about a fulcrum 23, and can swing between a position indicated by a solid line and a position indicated by an imaginary line in FIG.

  On the other hand, as shown in FIG. 3, a guide plate pressing portion 31 is formed at the center of the upper surface of the front (back side) wall 7 a of the paper feed cassette 7. When the paper feed cassette 7 is set to the printer body as shown in FIG. 1 by the guide plate pressing portion 31, the guide plate pressing portion 31 presses the double-sided guide plate 22, and the double-sided guide plate 22 is shown by a solid line in FIG. At this time, the driven rollers 13b and 14b supported by the double-sided guide plate 22 are pressed against the driving rollers 13a and 14a supported by the upper double-sided guide plate 21, and the double-sided conveyance path 30 is closed. The transfer paper can be conveyed (re-feeded). The guide plate pressing portion 31 is a holding portion that holds the double-sided guide plate 22 in a closed state. Note that a lower surface of the double-sided guide plate 22 is provided in correspondence with the guide plate pressing portion 31 of the sheet feeding cassette 7 and is provided with an abutting portion 24 with which the guide plate pressing portion 31 contacts (FIG. 4). reference).

  When the transfer paper conveyed through the refeed path 16 is jammed in the double-sided conveyance path 30, the double-sided conveyance path 30 is opened by pulling out the paper feed cassette 7 from the printer main body to perform jam processing.

  That is, when the paper feeding cassette 7 is pulled out from the printer main body, the pressing by the guide plate pressing portion 31 is released, so that the lower double-sided guide plate 22 rotates as indicated by phantom lines in FIG. The guide plates 21 and 22 are separated from each other, and the pressing of the driving rollers 13a and 14a and the driven rollers 13b and 14b is released. As a result, the double-sided conveyance path 30 is opened, and the jam handling operation can be easily performed. In order to perform the jam processing at this portion, an opening / closing door (not shown) is provided on the exterior cover of the printer, and the opening / closing door is opened during the jam processing.

  In this embodiment, as shown in FIGS. 1 and 3, a slope portion 32 is formed on the front surface (back side) of the paper feed cassette 7. In this example, the inclined surface portion 32 is formed integrally with the side walls (7a, 7b) of the paper feed cassette 7, but the inclined surface portion 32 may be configured by a separate member. In addition, the entire front surface of the sheet feeding cassette 7 may not be a slope portion, but only the front end portions of the left and right side walls 7b and 7b may be inclined to form an oblique side portion. Also in this case, the hypotenuse part may be formed integrally with the side walls 7b, 7b, or the hypotenuse part may be constituted by another member.

  In this embodiment, since a slope portion (or a hypotenuse portion) 32 as a guide portion is provided on the back side (front side in the cassette insertion direction) of the sheet feeding cassette 7, as shown in FIG. The cassette is inserted while the (slanted side) 32 comes into contact with the double-sided guide plate 22 and the inclined side (slanted side) 32 pushes the double-sided guide plate 22 upward. When the paper feed cassette 7 is inserted into the apparatus main body, the inclined surface portion (slope side portion) 32 pushes up the double-sided guide plate 22, and then the guide plate pressing portion 31 comes into contact with the contact portion 24 of the double-sided guide plate. The plate 22 is held in a closed position (a state where paper can be conveyed).

  As described above, when the paper feed cassette 7 is inserted, the double-sided guide plate 22 is automatically moved to the closed position (the state in which the paper can be conveyed). As described above, the double-sided guide plate 22 automatically moves to the open position when the paper feed cassette 7 is pulled out from the printer body. That is, by pulling out and inserting the paper feed cassette 7, the double-sided guide plate 22 is automatically moved to the open position (jam processing position) and the closed position (paper transport position). Therefore, it is possible to save the user from operating the double-sided guide plate 22 and improve the workability of the jam processing. Further, without forgetting to return the double-sided guide plate 22 to the closed position after the jam processing, damage to each part of the apparatus and inoperability of the apparatus can be prevented. It is preferable that the front side of the guide plate pressing portion 31 is formed in a slope shape along the slope portion (slope side portion) 32.

  FIG. 5 is a partial perspective view of a paper feed cassette showing a second embodiment in which the abutting portion between the double-sided guide plate and the paper feed cassette is provided at two locations in the direction orthogonal to the paper feed direction (cassette width direction). It is. The paper feed cassette 7B shown in this figure is configured such that guide plate pressing portions 31a and 31b are provided on the upper surfaces of the left and right side walls 7b and 7c, and the double-sided guide plates 22 are pressed on both sides of the cassette. . In this case, the contact portions (24) on the double-sided guide plate 22 side corresponding to the guide plate pressing portions 31a and 31b are also provided on the left and right sides (both sides in the direction orthogonal to the paper feeding direction). By pushing up and holding the double-sided guide plate 22 on both sides in the cassette width direction, the posture of the double-sided guide plate 22 is stabilized and the position of the double-sided guide plate 22 can be held with high accuracy.

  FIG. 6 is a cross-sectional view in the width direction of the paper feed cassette 7B of FIG. As shown in this figure, restricting members 35a and 35b for restricting the width direction end of the paper are provided in the cassette. The guide plate pressing portions 31a and 31b are provided outside the sheet passing area outside the regulating members 35a and 35b, and are provided regardless of the sheets stacked in the cassette. The position in the direction can be set arbitrarily (without being limited by the paper in the cassette).

  FIG. 7 is a cross-sectional view in the width direction of the paper feed cassette showing a third embodiment in which a contact portion between the double-sided guide plate and the paper feed cassette is provided only on one side in a direction orthogonal to the paper feed direction. The paper feed cassette 7C shown in this figure is provided with a guide plate pressing portion 31a only on one side in the width direction. On the double-sided guide plate 22 side, the contact portion (24) is also provided only on one side in the width direction, corresponding to the guide plate pressing portion 31a on only one side. Also in the case of the third embodiment, the guide plate pressing portion 31a is provided outside the sheet passing region that is outside the regulating members 35a and 35b.

  FIG. 8 is a partial cross-sectional view showing a fourth embodiment in which an elastic member is used as a cassette-side guide plate pressing portion that presses the double-sided guide plate 22. As shown in this figure, a guide plate pressing elastic member 33 is mounted on the upper surface of the front (back side) wall 7a of the paper feed cassette 7D. The guide plate pressing elastic member 33 may be provided at the center in the cassette width direction like the guide plate pressing portion 31 shown in FIG. 3, or the cassette width as shown in the guide plate pressing portions 31a and 31b shown in FIG. It may be provided on both sides of the direction. Of course, it is needless to say that the guide plate side contact portion 24 is provided corresponding to the position of the guide plate pressing elastic member 33.

  In the fourth embodiment shown in FIG. 8, when the paper feed cassette 7D is inserted into the apparatus body, the guide plate pressing elastic member 33 is moved to the double-sided guide after the inclined surface portion (slope side portion) 32 pushes up the double-sided guide plate 22. The double-sided guide plate 22 is held in a closed position (a state where paper can be conveyed) by contacting the plate contact portion 24. At this time, since the double-sided guide plate 22 is urged from below by the elastic force of the elastic member 33, the double-sided guide plate 22 is accurately held at the closed position (paper transport position) regardless of the positional accuracy of the paper feed cassette. Good conveyance accuracy in the duplex conveyance path 30 can be maintained. As the guide plate pressing elastic member 33, a member such as a leaf spring, rubber, or resin can be used.

  FIG. 9 shows a fifth embodiment in which a sliding member for reducing sliding friction is provided at the sliding portion between the double-sided guide plate 22 and the paper feed cassette 7. As shown in this figure, a sliding roller 25 is rotatably supported at the tip end portion of the double-sided guide plate 22 (contact portion with the inclined surface portion 32 of the paper feed cassette 7). The paper feed cassette 7D is the same as that in the fourth embodiment.

  In the fifth embodiment, when the sheet feeding cassette 7D is inserted, the sliding roller 25 is moved when the inclined surface portion (slanted side portion) 32 of the cassette comes into contact with the front end portion of the double-sided guide plate 22 and pushes up the double-sided guide plate 22. The sliding friction between the double-sided guide plate 22 and the paper feed cassette 7D is reduced by moving the slope portion (slope side portion) 32 while rotating. Therefore, the resistance when inserting the paper feed cassette is reduced.

  In FIG. 9, the sliding roller 25 is provided on the double-sided guide plate 22 side, but a plurality of sliding rollers may be arranged on the inclined surface (slope side) 32 side of the paper feed cassette 7. Further, it is possible to adopt a configuration in which a low friction member is attached to the double-sided guide plate 22 side, the paper feed cassette 7 side or both instead of the sliding roller. 9 shows an example in which the elastic member 33 is used as the cassette-side guide plate pressing portion, the guide plate pressing portion 31 in FIG. 3 or the guide plate pressing portions 31a and 31b in FIG. 5 may be used.

  Next, FIG. 10 shows a sixth embodiment in which a contact portion between the double-sided guide plate 22 and the paper feed cassette 7 is provided at a position far from the rotation fulcrum 23 of the double-sided guide plate 22. The sheet feeding cassette 7E shown in this figure has a guide plate pressing portion 34 on the upper surface of the cassette side wall. The guide plate pressing portions 34 are provided on the side walls on both sides in the cassette width direction, but may be only on one side. The guide plate pressing portion 34 is provided at a position corresponding to the distal end portion of the double-sided guide plate 22, which is a position away from the rotation fulcrum 23 of the double-sided guide plate 22. The contact portion 24 on the double-sided guide plate side is provided on the lower surface of the front end portion of the guide plate corresponding to the guide plate pressing portion 34 of the paper feed cassette 7E. The front portion of the guide plate pressing portion 34 in the cassette insertion direction is formed in a slope shape so that the guide plate pressing portion 34 can easily push up the contact portion 24 when the cassette is inserted. In the configuration of the sixth embodiment, the guide plate pressing portion 34 of the paper feed cassette 7E presses the double-sided guide plate 22 at a position far from the rotation fulcrum 23 and holds it in the closed position (paper transport position). Since the posture of the plate 22 is stable and is reliably held in the paper conveyance state, good conveyance accuracy in the double-side conveyance path 30 can be maintained. As the guide plate pressing portion 34, an elastic member as described with reference to FIGS.

  FIG. 11 shows a seventh embodiment in which the drive-side roller of the double-sided conveyance path 30 is mounted on the lower-side double-side guide plate 22. In the seventh embodiment, as shown in the drawing, driven rollers 13b and 14b constituting the conveying rollers 13 and 14 are mounted and supported on the upper double-sided guide plate 21. The driving rollers 13a and 14a are mounted and supported on the lower double-sided guide plate 22. A drive gear 26 is attached to the shaft end of the drive roller 13a. In the seventh embodiment, the center of rotation (swing) of the double-sided guide plate 22 is provided coaxially with the axis of the drive roller 13a. Therefore, the position of the drive gear 26 does not move even when the paper feed cassette 7 swings. A transmission gear 27 is arranged so as to mesh with the drive gear 26. The transmission gear 27 is rotated by a drive source (motor) (not shown), whereby the drive roller 13a is rotationally driven.

  The drive roller 14a at the tip of the double-sided guide plate 22 may be configured to be driven by a gear train (not shown) from the drive gear 26, or the shaft of the drive roller 14a when the double-sided guide plate 22 is moved to the closed position. It may be configured such that the gear provided in the gear meshes with the drive system of the apparatus main body. Alternatively, in the transport roller 14 at the tip of the double-sided guide plate 22, the upper side may be a drive roller and the lower side (the double-sided guide plate 22 side) may be a driven roller as shown in FIG.

  In the seventh embodiment, the rotation (swing) center of the double-sided guide plate 22 is coaxial with the axis of the drive roller 13a, so that the drive roller 13a is provided on the lower (rotating) double-sided guide plate 22. Even with this configuration, the configuration of the drive transmission system to the drive roller 13a does not become complicated, and the complexity and size of the configuration can be suppressed.

  As mentioned above, although this invention was demonstrated by the example of illustration, this invention is not limited to this. For example, the guide plate pressing elastic member 33 (FIG. 8) of the sheet feeding cassette 7D of the fourth embodiment can be provided as a guide plate pressing portion of the sheet feeding cassette of another embodiment. Further, the sliding roller 25 (FIG. 9) provided on the double-sided guide plate 22 in the fifth embodiment can also be provided on the double-sided guide plate 22 of other examples. The same applies to the low friction member. Furthermore, the position of the guide plate pressing portion and the corresponding contact portion on the double-sided guide plate side can also be set to an appropriate position.

  The configuration of each part of the image forming apparatus is also arbitrary, and the form of the double-sided conveyance path can be arbitrarily set. Further, the present invention can be applied not only to a monochrome apparatus but also to a color image forming apparatus. Of course, the image forming apparatus is not limited to a printer, and may be a copier, a facsimile machine, or a multifunction machine having a plurality of functions.

1 is a cross-sectional configuration diagram illustrating an outline of a printer which is an example of an image forming apparatus according to the present invention. It is a schematic diagram which shows opening and closing of a double-sided conveyance path. FIG. 6 is a partial perspective view showing the vicinity of a guide plate pressing portion provided in a paper feed cassette. It is a schematic diagram which shows the operation | movement at the time of cassette insertion. It is a fragmentary perspective view which shows the paper feed cassette of 2nd Example. It is sectional drawing of the width direction of the paper feed cassette. It is sectional drawing of the width direction of the paper feed cassette of 3rd Example. It is a schematic diagram which shows the structure and operation | movement of 4th Example. It is a schematic diagram which shows the structure and operation | movement of 5th Example. It is a fragmentary sectional view showing the composition of the 6th example. It is a schematic diagram which shows the structure and operation | movement of 7th Example.

Explanation of symbols

1 Photosensitive drum 5 Fixing device 7 Paper feed cassette (sheet storage means)
DESCRIPTION OF SYMBOLS 10 Paper reversing part 13, 14 Carrying roller pair 13a, 14a Drive roller 13b, 14b Driven roller 15 Switchback conveyance path 16 Refeed conveyance path 21 Upper both-side guide plate (conveyance path forming member)
22 Lower both-side guide plate (conveying path forming member, adjacent forming member)
23 oscillating fulcrum 24 contact part 25 sliding roller (friction reduction means)
30 Double-sided conveyance path 31, 34 Guide plate pressing part (holding part)
32 Slope, hypotenuse (guide)
33 Guide plate pressing elastic member 26 Drive gear 27 Transmission gear 100 Printer

Claims (12)

A sheet storage means detachably attached to the apparatus main body, a sheet reversing unit for reversing the front and back of a sheet on which an image is recorded on one side, and a refeeding path for conveying the sheet reversed by the sheet reversing unit to the image forming unit again An image forming apparatus having at least a part of the refeed path provided as a double-sided conveyance path along the sheet storage unit.
Of the conveyance path forming members constituting the double-sided conveyance path, a forming member adjacent to the sheet storage means has a first position for opening the double-sided conveyance path, and a second position for closing the double-sided conveyance path. Provided to be movable,
2. The image forming apparatus according to claim 1, wherein the adjacent forming member is moved to the first position and the second position by the attachment / detachment of the sheet storage unit. The image forming apparatus according to claim 1, wherein a holding portion that holds the adjacent forming member at the second position when the sheet storage unit is mounted on the apparatus main body is provided in the sheet storage unit. apparatus. 3. The image forming apparatus according to claim 1, wherein the adjacent forming members are provided so as to be swingable with a vicinity of an upstream end portion in a sheet conveying direction as a fulcrum. A holding portion for holding the adjacent forming member in the second position in the vicinity of the end of the forming member opposite to the fulcrum when the sheet storing unit is mounted on the apparatus main body is provided in the sheet storing unit. The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. The image forming apparatus according to claim 2, wherein an elastic member is provided in the holding portion, and the elastic member biases the adjacent forming member in the second position direction. The image forming apparatus according to claim 2, wherein the holding unit is provided outside the sheet passing area. The image forming apparatus according to claim 2, wherein the holding portions are provided on both sides in a sheet width direction orthogonal to the sheet feeding direction. The image forming apparatus according to claim 1, wherein a guide portion that contacts the adjacent forming member and guides the movement of the adjacent forming member is provided on the front side in the insertion direction of the sheet storage unit. The friction reducing means for reducing sliding friction is provided at a sliding contact portion where the sheet storing means and the adjacent forming member are in sliding contact when the sheet storing means is attached and detached. Image forming apparatus. The image forming apparatus according to claim 9, wherein the friction reducing unit is a sliding roller. The image forming apparatus according to claim 9, wherein the friction reducing unit is a low friction member. A pair of conveying rollers is disposed in the double-sided conveying path, and a driving roller of the conveying roller pair is supported by the adjacent forming member, and the adjacent forming member can swing around the shaft of the driving roller. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided in the image forming apparatus.

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