JP2013086968A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve conveyance performance of an image forming apparatus with a conveyance mechanism conveying a recording medium (for example, a form) to a process unit performing image forming.SOLUTION: In an image forming apparatus 1, a hand insertion unit 90 is opened by rotating in a horizontal plane together with an internally installed rotor 92 etc., and a hand-insertion side guide member 94 to expose a cassette-side guide member 54 and the hand-insertion side guide member 94, and the hand-insertion side guide member 94 is configured to be opened by rotating in a vertical surface for jam processing at the roller 92 etc. The image forming apparatus 1 further includes a positioning mechanism 100 having a first energizing member 101 energizing the hand-insertion side guide member 94, opened on the jam processing, in a closing direction, and a second energizing member 102 holding the hand-insertion side guide member 94 stationary at a predetermined position.

Description

  The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus including a transport mechanism that transports a recording medium (for example, paper) to a process unit that performs image formation.

  As a conventional image forming apparatus, for example, there is one described in Patent Document 1 below. This image forming apparatus is provided with first to fourth paper feed units. The first sheet feeding unit and the second sheet feeding unit are arranged above and below, and the third sheet feeding unit and the fourth sheet feeding unit are arranged on the left and right below the second sheet feeding unit. The sheets stacked in each sheet feeding unit are sent out to the sheet passing path one by one. In addition, a circulation path for double-sided printing is provided on the side of the image forming apparatus, and a manual paper feed unit is provided below the circulation path.

  The conveyance path for guiding the sheet from the second to fourth sheet feeding units to the transfer area includes a sheet feeding conveyance path for guiding the sheet from the first sheet feeding unit to the conveyance path, and a manual conveyance path for guiding the sheet from the manual feeding unit to the conveyance path. Are merged at the same merge point. A paper feed movable guide, a manual feed movable guide, and a manual feed unit are provided around the junction.

  The sheet feed movable guide is attached so as to be rotatable around an axis at the lower end between the transport path upstream of the junction and the sheet feed transport path. The paper feed movable guide has a guide surface for a paper feed conveyance path and a guide surface for a conveyance path for guiding paper from upstream. The paper feed movable guide is urged in a direction to close the paper feed transport path by a spring (not shown).

  The manual feed movable guide is attached to the manual feed unit so as to be rotatable around a lower end axis between the manual feed path and the carry path. The manual feed movable guide has a guide surface for a manual transport path and a guide surface for a transport path that guides paper from upstream. The manual feed movable guide is biased in a direction to close the manual feed path by a spring (not shown).

  The manual feed unit is attached to the outside of the first paper feed unit on the outer side of the apparatus main body so that it can be opened and closed independently in the horizontal direction around the axis provided for the jam processing. When a jam occurs, the user opens the manual feed unit along with the manual feed movable guide in the horizontal direction around the back axis. After that, for example, the user opens the paper feed movable guide around the shaft against the biasing force of the spring, and removes the paper in the paper feed conveyance path.

JP 2008-137748 A (pages 4 to 6)

  As described above, the paper feed movable guide is rotatable about the lower end axis and is biased in the direction of closing the paper feed conveyance path. The manual feed movable guide is rotatable around a lower end axis and is biased in a direction to close the manual feed path. For this reason, the guide surface of the conveyance path for guiding the sheet from the upstream in the paper feed movable guide and the manual feed movable guide may not be maintained parallel to the vertical direction and may be inclined. Due to this inclination, the sheet sent out from the conveyance path is not correctly introduced into the nip between the conveyance roller and the driven roller pressed against the conveyance roller, but is caught by another guide member, and the sheet is skewed. There was a problem that ear breakage may occur.

  In view of the above problems, an object of the present invention is to provide an image forming apparatus provided with a transport mechanism that improves the transport performance by reducing the occurrence of skew or folds in the recording medium.

  In order to achieve the above object, one aspect of the present invention is an image forming apparatus that conveys a recording medium to a process unit for image formation, and is disposed below the process unit and stores the recording medium. Recording from an upper supply cassette and a lower supply cassette, a first roller group and a second roller group that take out and send out a recording medium from the upper supply cassette and the lower supply cassette, and recording from the first roller group A cassette-side guide member having a first guide surface for guiding a medium and a second guide surface for guiding a recording medium from the second roller group; and an upper supply cassette disposed in a lateral direction, A manual feed unit on which the recording medium is placed, a third roller group for taking out the recording medium from the manual feeding unit and feeding it, and a recording medium from the third roller group A third guide surface that guides the recording medium, and a second guide surface that is laterally opposed to the second guide surface, and guides the recording medium from the second roller group together with the second guide surface. A manual guide member having a fourth guide surface, and a recording medium guided by the first guide surface, the third guide surface, or the second and fourth guide surfaces. And a pair of vertical conveying rollers for feeding the recording medium toward the upper process unit. The manual feed unit rotates in a horizontal plane together with the third roller group and the manual guide member to open the cassette side guide member and the manual guide member. The manual-feed-side guide member is configured to rotate and open in a vertical plane for jam processing by the third roller group. The image forming apparatus further includes a first urging member that urges the manual-feed-side guide member that is opened during the jam processing in a closing direction, and a second attachment that causes the manual-feed-side guide member to be stopped at a predetermined position. And a positioning mechanism having a biasing member.

  With the above-described configuration, it is possible to provide an image forming apparatus including a transport mechanism that reduces the occurrence of skew or ear folds in the recording medium and improves the transport performance.

1 is an external perspective view of an image forming apparatus. FIG. 2 is a schematic diagram illustrating an internal configuration of the image forming apparatus in FIG. 1. FIG. 3 is a cross-sectional view illustrating a configuration around a supply cassette and a manual feed unit of FIG. 2. It is sectional drawing which expands and shows the circumference | surroundings of conveyance path R1, R5 and common conveyance path Ra. FIG. 3 is a perspective view of the image forming apparatus 1 when the manual feed unit of FIG. 2 is opened. (A), (B) is a perspective view which shows the structure of a positioning mechanism. (A) is a schematic diagram showing the initial angle θ of the guide surface, and (B) is a graph showing the strength of the first and second urging members with respect to the initial angle θ. (A)-(C) is a mimetic diagram showing manual operation at the time of jam processing. (A)-(C) is a mimetic diagram showing manual operation after jam processing. (A)-(C) are schematic diagrams which show a problem assumed when the initial angle is θ> 45 °.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. In each drawing, an X axis, a Y axis, and a Z axis indicate a left-right direction (lateral direction), a depth direction (front-rear direction), and a height direction (up-down direction) of the image forming apparatus. In the following, the capital letters Y, M, C, and K that follow the reference numerals represent yellow, magenta, cyan, and black. For example, the photoconductor drum 10Y means the photoconductor drum 10 for yellow.

(About schematic configuration of image forming apparatus)
1 and 2, an image forming apparatus 1 is a copying machine, for example, and includes a main body 2 and a reading unit 4. The reading unit 4 is a scanner that reads a document and generates image data. The main body 2 forms an image on a recording medium (for example, paper) based on the image data generated by the reading unit 4.

  A process unit 2 a for image formation is provided on the upper stage of the main body 2. As shown in FIG. 2, the process unit 2a is roughly composed of photosensitive drums 10Y, 10M, 10C, and 10K, developing devices 15Y, 15M, 15C, and 15K, an intermediate transfer unit 20, a laser scanning unit 30, and a fixing unit 40. It has.

  Further, as shown in FIGS. 1 and 2, a transport mechanism 2 b is provided at the lower stage of the main body 2. The transport mechanism 2b generally includes supply cassettes 50, 60, 70, and 80 and a manual feed unit 90, and is a mechanism for transporting sheets stacked on these to the process unit 2a. The supply cassette 50 is a typical example of the upper supply cassette, and is disposed directly below the laser scanning unit 30. A supply cassette 60 is disposed directly below the supply cassette 50. Supply cassettes 70 and 80 are arranged directly below the supply cassette 60. The supply cassettes 70 and 80 are arranged side by side in the horizontal direction. The above supply cassettes 60, 70, 80 are typical examples of the lower supply cassette. The manual feed unit 90 is provided on the right side face toward the main body 2 so as to face the supply cassette 50 in the lateral direction.

  As shown in FIG. 2, the developing devices 15Y, 15M, 15C, and 15K include toner storage portions 16Y, 16M, 16C, and 16K and developing rollers 17Y, 17M, 17C, and 17K. The intermediate transfer unit 20 includes an intermediate transfer belt 21 that is endlessly held by a driving roller 22 and a driven roller 23, and includes primary transfer rollers 24Y, 24M, 24C, and 24K.

  In the image forming process, a light beam modulated with image data of each color is irradiated from the laser scanning unit 30 to the photosensitive drums 10Y, 10M, 10C, and 10K, and an electrostatic latent image is formed on the photosensitive drum 10. Next, the electrostatic latent images of the respective colors are developed (toner images) by the corresponding color developing devices 15Y, 15M, 15C, and 15K. This toner image is primarily transferred onto the intermediate transfer belt 21 by an electric field applied from the primary transfer rollers 24Y, 24M, 24C, and 24K for each color, and four color images are superimposed on the intermediate transfer belt 21. .

  In the image forming process, the paper is transported through one of transport paths R1 to R5 (details will be described later) in the transport mechanism 2b, and passes through the vertical transport rollers 121a and 121b as an example of a pair of vertical transport rollers, and then the process unit 2a. To be supplied. In the process unit 2a, the sheet is introduced into a nip portion (secondary transfer portion) between the intermediate transfer belt 21 and the secondary transfer roller 27 supported by the driving roller 22 through registration rollers 124a and 124b. Then, the composite image is secondarily transferred from the intermediate transfer belt 21 to the sheet by the electric field applied from the secondary transfer roller 27. Thereafter, the sheet is heated and fixed with toner by the fixing unit 40 and is discharged from the discharge roller pair 130 onto the sheet tray 131.

  Further, when forming an image on both sides of the paper, the paper on which the image is formed on the first side is switched back by the pair of reverse rollers 132 and sent out to the return conveyance path R6. Then, the fed sheet passes through the registration rollers 124 a and 124 b, the secondary transfer unit, and the fixing unit 40 again to form an image on the second surface, and is discharged from the discharge roller pair 130 onto the sheet tray 131. Is done.

(About the outline of the transport path)
Below, conveyance path | route R1-R5 is demonstrated. As shown in FIG. 2, the conveyance paths R1, R2, R3, and R4 are paths through which the sheets stacked on the supply cassettes 50, 60, 70, and 80 are conveyed. As a typical example of the first roller group, a pickup roller 51, a paper feed roller 52, and a separation roller 53 are provided on the transport path R1. On the transport path R2, a pickup roller 61, a paper feed roller 62, and a separation roller 63 are provided as an example of a second roller group. As another example of the second roller group, a pickup roller 71, a paper feed roller 72, and a separation roller 73 are provided on the transport path R3. On the transport path R4, a pickup roller 81, a paper feed roller 82, and a separation roller 83 are provided as still another example of the second roller group. The conveyance path R5 is a path through which the paper placed on the manual feed unit 90 passes. On the transport path R5, a pickup roller 91, a paper feed roller 92, and a separation roller 93 are provided as an example of a third roller group.

  Each pickup roller 51, 61, 71, 81 takes in paper from the supply cassette 50, 60, 70, 80 immediately upstream thereof. The pickup roller 91 takes in the paper from the manual feed unit 90 immediately upstream. The feed rollers 52, 62, 72, 82, 92 and the separation rollers 53, 63, 73, 83, 93 form a pair, and the pickup rollers 51, 61, 71, 81, 91 immediately upstream of each pair are taken out. The sheets are separated one by one and placed on the transport paths R1, R2, R3, R4, R5.

  The conveyance paths R1 to R5 merge with other paths on the way. Specifically, the transport paths R3 and R4 merge at the nip between the intermediate rollers 123a and 123b. The conveyance paths R2, R3, and R4 are joined by vertical conveyance rollers 122a and 122b provided downstream of the intermediate rollers 123a and 123b. Further, the transport paths R1, R2, R3, R4, and R5 merge at the nip Na (see FIG. 4) of the vertical transport rollers 121a and 121b provided downstream of the vertical transport rollers 122a and 122b.

(Details of transport path R1)
As shown in FIG. 3, in the supply cassette 50, the sheets are stacked on a push-up plate 50b provided on the bottom 50a. In addition, on the upper right side of the supply cassette 50, the above-described pickup roller 51, the paper feed roller 52, and the separation roller 53 are provided. The pickup roller 51 takes out the paper stacked on the push-up plate 50b. As shown in FIG. 4, the taken-out paper is placed on the transport path R <b> 1 and then introduced into the nip N <b> 1 between the paper feed roller 52 and the separation roller 53. Only one sheet is separated by the sheet feed roller 52 and the separation roller 53 and passes through the nip N1.

  A guide surface F1 of the cassette side guide member 54 is provided immediately downstream of the nip N1. The guide surface F1 is a typical example of the first guide surface, and is inclined obliquely upward to the right with respect to the XY plane (substantially horizontal plane). The sheet that has passed through the nip N1 is transported on the transport path R1 along the guide surface F1, and is introduced into the nip Na of the vertical transport rollers 121a and 121b disposed substantially above the downstream of the guide surface F1.

(Details of transport path R5)
In FIG. 3, a manual feed unit 90 is provided for printing an image on a sheet desired by the user. The manual feed unit 90 includes a paper feed tray 90a and a manual paper feed stand 90b. The sheet feeding tray 90a can be rotated in a vertical (ZX plane) plane as shown by an arrow A in FIG. 3 so as to be stored in the main body of the image forming apparatus when not in use, and in a horizontal plane (XY plane). However, it is stationary in a state where it is tilted upward by about 10 °. In this state, the paper is placed on the paper feed tray 90a. Further, the manual paper feed stand 90b biases the front end portion of the paper on the paper feed tray 90a upward.

  A pickup roller 91 is provided above the manual sheet feeding table 90b. The pickup roller 91 is in contact with the leading end portion of the paper urged by the manual paper feed table 90b. A pair of a paper feed roller 92 and a separation roller 93 is provided immediately downstream of the pickup roller 91. By the rotation of the pickup roller 91, the sheet is taken in from the manual sheet feeding table 90b. As shown in FIG. 4, the taken-in paper is placed on the conveyance path R <b> 5 and then introduced into the nip N <b> 5 between the paper feed roller 92 and the separation roller 93. By rotating the sheet feeding roller 92 and the separation roller 93, only one sheet is separated and passes through the nip N5.

  As shown in FIG. 4, a guide surface F5 of the manual feed side guide member 94 is provided immediately downstream of the nip N5. The guide surface F5 is an example of a third guide surface, and is inclined to the upper left with respect to the XY plane. The sheet that has passed through the nip N5 is transported along the guide surface F5 along the transport path R5 and then introduced into the nip Na that is downstream of the guide surface F5.

(Details of common transport path Ra)
Still referring to FIG. The cassette side guide member 54 has a guide surface Fa1 on the right side of the guide surface F1 in addition to the above-described guide surface F1. Specifically, the guide surface Fa1 is an example of a second guide surface, and is formed to extend from the uppermost end of the guide surface F1 in a direction directly below lead. The guide surface Fa1 extends leftward at the lower end portion so that the sheet from the upstream can be easily introduced into the common transport path Ra.

  The manual feed side guide member 94 has a guide surface Fa2 on the left side of the guide surface F5 in addition to the above-described guide surface F5. Specifically, the guide surface Fa2 is an example of a fourth guide surface, and extends from the uppermost end of the guide surface F5 in a direction directly below lead. The guide surface Fa2 extends rightward at the lower end portion with the same purpose as the guide surface Fa1.

  The above-described guide surfaces Fa1 and Fa2 are opposed to each other in the lateral direction with a gap. This gap is used as a common transport path Ra. That is, the sheets from the supply cassettes 60, 70, and 80 are introduced from the vertical conveyance rollers 122a and 122b to a conveyance path Ra provided on the downstream side thereof. The introduced sheets are guided along the guide surfaces Fa1 and Fa2 in the common conveyance path Ra, and are introduced into the nip Na of the vertical conveyance rollers 121a and 121b provided on the downstream side and the upper side.

(Jam handling mechanism)
In addition, the manual feed unit 90 also functions as a door operated by the user at the time of jam processing. Therefore, as shown in FIG. 5, the manual feed unit 90 has a rotation axis A3 that is parallel to the vertical direction at the right back toward the image forming apparatus 1. doing. The manual feed unit 90 is configured to be rotatable in a horizontal plane around the rotation axis A3. By opening the manual feed unit 90, the cassette side guide member 54 and the manual side guide member 94 are exposed.

  In addition, the image forming apparatus 1 includes a positioning mechanism 100 in order to achieve both the ease of jam processing and the conveyance performance of a common conveyance path Ra. FIGS. 6A and 6B are enlarged views of the dotted frame in FIG. 5, that is, the vicinity of the first side end face Fs <b> 1 of the manual feed side guide member 94. The first side end surface Fs1 is a side end surface that is substantially orthogonal to the guide surface Fa2 and parallel to the Z-axis. Although there are two such side end faces, the first side end face Fs1 is the front side toward the image forming apparatus 1 when the manual feed unit 90 is closed. Further, as shown in FIG. 5, the second side end face Fs2 is substantially opposed to the first side end face Fs2 with the guide surface Fs2 interposed therebetween, and the image forming apparatus 1 is closed when the manual feed unit 90 is closed. Located on the back side when viewed from the front.

  6A and 6B, around the side end face Fs1 described above, as a part of the configuration of the positioning mechanism 100, the rotary shaft A2, the bearing member 101, and the first and second urging members. 102 and 103 are provided.

  The rotation axis A2 protrudes from the lower end of the side end face Fs1. The bearing member 101 is fixed to the manual feed unit 90, and supports the rotary shaft A2 so as to be rotatable in a vertical plane by a user's manual operation. In FIG. 6B, the bearing member 101 and the following first biasing member 102 are not shown for convenience.

  The first urging member 102 is, for example, a tension coil spring. Hooks are provided at both ends of the tension coil spring. One hook is locked to a hole 104 formed on one side end surface and above the rotation axis A2. The other hook is locked in a hole 105 formed in the bearing member 101. The first urging member 102 applies a force (direction indicated by an arrow C in FIG. 4) in a direction to close the manual feed side guide member 94 (that is, the transport path R5).

  The second biasing member 103 is typically a torsion coil spring. The coil portion of the torsion coil spring is inserted through the rotation axis A2. The arms at both ends of the torsion coil spring are bent, and one arm is inserted through a hole 106 formed on one side end surface. The other arm is inserted through a hole 107 formed in the manual feed unit 90. The second urging member 103 applies a force in the direction to open the manual feed guide member 94 (that is, the transport path R5) (in the direction opposite to the arrow C in FIG. 4).

  Here, the initial angle θ of the guide surface Fa2 is defined as follows. As shown in FIG. 7A, the initial angle θ is an angle that the guide surface Fa2 makes with the Z-axis when the manual feed unit 90 is opened. When the manual feed unit 90 is opened, the guide surface Fa2 stops at this initial angle θ. Here, when θ is 0 °, the guide surface Fa2 is parallel to the Z axis, and the direction in which the transport path R5 is opened is positive. The amount of force of the first urging member 102 and the second urging member 103 is selected so that the initial angle θ falls within the range of 0 ° ≦ θ ≦ 45 °. For example, as shown in FIG. 7B, when the force of the first and second urging members 102 and 103 is approximately 2.1 [N], the initial angle θ is about 12.6 °.

  The same configuration as the rotation shaft A2, the bearing member 101, the first and second urging members 102 and 103, and the holes 104 to 107 is provided on the second side end face Fs2 (see FIG. 5). In addition, the same configuration as that of the rotation shaft A2, the bearing member 101, the first and second urging members 102 and 103, and the holes 104 to 107 is preferably provided on both side end surfaces Fs3 and Fs4 ( (See FIG. 5).

  Further, as shown in FIGS. 6A and 6B, two protrusions 108 are provided perpendicularly to the guide surface Fa2 at one end in the longitudinal direction of the guide surface Fa2. Although not shown, a similar protrusion 108 is provided at the other end. Here, as shown in FIG. 4, the longitudinal direction is a direction parallel to the Y-axis direction when the manual feed unit 90 is closed. The height of each protrusion 108 with respect to the guide surface Fa2 is designed to a value (for example, about 2 to 3 mm) that allows the paper from the common transport path Ra to be correctly introduced into the nip Na. The distance between the two protrusions 108 is designed according to the maximum sheet that can be handled by the image forming apparatus 1.

(About jam processing)
In the image forming apparatus configured as described above, the jam processing is performed as follows. At the time of image formation, as shown in FIG. 8A, the guide surfaces Fa1 and Fa2 face each other in the horizontal direction at an interval (for example, 2 to 3 mm) corresponding to the height of the protrusion 108. When an image is formed on paper stacked on the manual feed unit 90, the paper is transported through a transport path R5. At this time, if a paper jam occurs at the nip N5, the user manually opens the manual feed unit 90 as shown in FIG. 8B. As a result, the guide surface Fa2 is inclined by the initial angle θ. The user opens the manual feed unit 90 as much as necessary, and then opens the manual feed side guide member 94 with a finger or the like as shown in FIG. 8C to remove the paper.

  After removing the paper, the user releases his / her finger from the manual feed side guide member 94. At this time, the guide surfaces Fa1 and Fa2 are inclined at the initial angle θ with respect to the Z axis as shown in FIG. 9A by the biasing members 101 and 102 of the positioning mechanism 100 described above. After releasing the finger, the user closes the manual feed unit 90 as shown in FIGS. 9B to 9C. During this time, the guide surface Fa2 approaches the guide Fa1, and after both protrusions 108 come into contact with the guide surface Fa1, the guide surfaces Fa1 and Fa2 are urged in the directions of arrows B and C in FIG. Finally, the guide surfaces Fa1 and Fa2 face each other in the horizontal direction at an interval (for example, 2 to 3 mm) corresponding to the height of the protrusion 108, and return to the initial position immediately upstream of the nip Na of the vertical conveying rollers 121a and 121b. To do.

  As described above, the guide mechanism Fa1 and Fa2 are inclined at the initial angle θ by the two types of urging members 101 and 102 when the manual feed unit 90 is opened by the positioning mechanism 100. Further, when the manual feed unit 90 is closed, the distance between the guide surfaces Fa1 and Fa2 is secured by the two protrusions 108, and the common transport path Ra returns immediately upstream of the nip Na. Accordingly, the sheet is correctly introduced from the transport path Ra to the nip Na, and it is possible to reduce the occurrence of skew or folds in the sheet. As described above, by providing the positioning mechanism 100, it is possible to provide an image forming apparatus with improved conveyance performance.

  As described above, the initial angle θ is 0 ° ≦ θ ≦ 45 °. If θ> 45 °, as shown in FIGS. 10A to 10C, when closing the manual feed unit 90, the guide surface Fa2 hits the guide surface Fa1, and then rotates downward. The manual feed unit 90 may not be closed properly. In order to prevent this, the initial angle θ is set to 0 ° ≦ θ ≦ 45 °.

(Appendix)
In the above embodiment, the two protrusions 108 are both provided on the guide surface Fa2. However, the present invention is not limited to this, and both of the two protrusions may be provided on the guide surface Fa1, or one of the two protrusions may be provided on the guide surface Fa1, and the other may be provided on the guide surface Fa2. Absent.

  In the above embodiment, a tension coil spring is used as the first biasing member 101, and a torsion coil spring is used as the second biasing member 102. However, the present invention is not limited to this, and the first and second urging members 101 and 102 may be realized by other means.

  The fixing device according to the present invention can improve the conveyance performance, and can be applied to a tandem type electrophotographic printer, a facsimile, a complex machine of these, etc. in addition to a copying machine.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2a Process unit 2b Conveyance mechanism 50, 60, 70, 80 Supply cassette 90 Manual feed unit 52,92 Paper feed roller 53,93 Separation roller 54 Cassette side guide member 94 Manual feed side guide member 121a, 121b Vertical conveyance roller R1 ~ R5 Transport path Ra Common transport path N1, N5, Na Nip F1, F5, Fa1, Fa2 Guide surface

Claims (6)

An image forming apparatus for conveying a recording medium to a process unit for image formation,
An upper supply cassette and a lower supply cassette that are respectively disposed below the process unit and store a recording medium;
A first roller group and a second roller group that take out and send out a recording medium from the upper supply cassette and the lower supply cassette;
A cassette-side guide member having a first guide surface for guiding the recording medium from the first roller group, and a second guide surface for guiding the recording medium from the second roller group;
A manual feed unit that is disposed opposite to the upper supply cassette in the lateral direction and on which a recording medium is placed;
A third roller group for taking out and sending out the recording medium from the manual feed unit;
A third guide surface that guides the recording medium from the third roller group, and a laterally opposed arrangement with a gap from the second guide surface, the recording medium from the second roller group is arranged. A manual-feed-side guide member having a fourth guide surface that jointly guides the second guide surface;
Longitudinal conveying rollers for introducing the recording medium guided by the first guide surface, the third guide surface, or the second and fourth guide surfaces and feeding the recording medium toward the upper process unit With a pair,
The manual feed unit rotates and opens in a horizontal plane together with the third roller group and the manual feed guide member to expose the cassette guide member and the manual feed guide member,
The manual feed side guide member is configured to rotate and open in a vertical plane for jam processing in the third roller group,
The image forming apparatus further includes:
A positioning mechanism comprising: a first urging member that urges the manual-feed-side guide member that is opened during the jam processing in a closing direction; and a second urging member that causes the manual-feed-side guide member to be stopped at a predetermined position. An image forming apparatus. The first biasing member is a tension coil spring;
2. The torsion coil spring according to claim 1, wherein the second urging member is a torsion coil spring that urges the manual guide member in the opening direction in order to make the manual guide member stationary at a predetermined position. Image forming apparatus.   The image forming apparatus according to claim 1, wherein when the manual feed unit is opened, the manual feed side guide member stops at a position where the manual feed unit can be closed.   The image forming apparatus according to claim 1, wherein when the manual feed unit is opened, the fourth guide surface is stationary within a range of 0 ° to 45 ° with respect to a vertical direction.   The positioning mechanism has a protrusion on the second guide surface or the fourth guide surface in order to secure a gap between the second guide surface and the fourth guide surface. The image forming apparatus according to any one of the above. The cassette side guide member is configured to be rotatable in a vertical plane for jam processing in the first roller group,
The positioning mechanism is
A third urging member that urges the cassette side guide member in a direction to close the cassette side guide member that was opened during the jam processing, and a fourth urging force that causes the cassette side guide member to be stationary at a predetermined position. The image forming apparatus according to claim 1, further comprising a member.

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