Image forming apparatus

Abstract

To provide an image forming apparatus that can stabilize its operation and reliably retract a recording medium.SOLUTION: An image forming apparatus comprises a housing, a stationary unit 102, a movable unit 101, a movable roller 132, and a drive mechanism 150. The stationary unit 102 is fixed to the housing, and has a conveyance path for conveying a recording medium. The movable unit 101 is withdrawably accommodated in the housing, and has a conveyance path communicating with the conveyance path of the stationary unit 102. The movable roller 132 is provided on one of the stationary unit 102 and the movable unit 101, and conveys the recording medium. When the movable unit 101 is withdrawn from the housing, the drive mechanism 150 rotates the movable roller 132 with a force to withdraw the movable unit 101.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to an image forming apparatus.

Background Art

[0002] Conventionally, in an image forming apparatus, in order to remove paper from the housing when maintenance inspection or paper jamming occurs, it has a fixed unit fixed to the housing and a movable unit that can be pulled out. Further, when paper jamming occurs, the paper may remain across the fixed unit and the movable unit. In this state, when the movable unit is pulled out from the housing, the paper may be torn. To solve such problems, for example, there is one described in Patent Document 1.

[0003] Patent Document 1 describes a technique having a mechanism for pulling back the recording medium fed to a refeeding unit movable between a mounting position and a detachment position with respect to the image forming apparatus main body to the refeeding unit. Then, when a jam occurs and a lever for moving the refeeding unit to the detachment position is operated, the pulling-back mechanism operates in conjunction therewith, and the recording medium straddling between the paper feeding mechanism and the apparatus main body is pulled back to the refeeding unit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technique described in Patent Document 1, in order to pull back the recording medium to the unit, the shaft of the drive unit is constantly pulled by a spring. As a result, the shaft of the drive unit is inclined, the meshing with the rack gear becomes unstable, and there is a problem that malfunction such as the spring cannot be pulled occurs.

[0006] In view of the conventional problems as described above, an object of the present invention is to provide an image forming apparatus that achieves stable operation and can reliably retract a recording medium.

Means for Solving the Problems

[0007] To solve the above problems and achieve the object of the present invention, an image forming apparatus includes a housing, a fixed unit, a movable unit, a movable roller, and a drive mechanism. The fixed unit is fixed to the housing and has a conveyance path for conveying a recording medium. The movable unit is removably accommodated in the housing and has a conveyance path communicating with the conveyance path of the fixed unit. The movable roller is provided on one of the fixed unit and the movable unit and conveys the recording medium. The drive mechanism rotates the movable roller by the force of pulling out the movable unit when the movable unit is pulled out from the housing.

Effects of the Invention

[0008] According to the image forming apparatus having the above configuration, stable operation can be achieved and the recording medium can be reliably retracted.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments for carrying out the present invention will be described with reference to FIGS. 1 to 19. In the figures, common members are denoted by the same reference numerals. Note that the present invention is not limited to the following embodiments.

[0011] 1. First Embodiment Example 1-1. Configuration of Image Forming Apparatus First, the overall configuration of an image forming apparatus according to the first embodiment example of the present invention (hereinafter referred to as "this example") will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing the image forming apparatus 1 of this example, and FIG. 2 is a schematic configuration diagram of the image forming apparatus 1 of this example.

[0012] The image forming apparatus 1 of this example forms an image on a sheet by an electrophotographic method, and is a tandem type color image forming apparatus that superimposes four colors of toner: yellow (Y), magenta (M), cyan (C), and black (Bk).

[0013] As shown in FIGS. 1 and 2, the image forming apparatus 1 includes a hollow housing 2, a cover 3, an original document conveying unit 4 installed on the upper part of the housing 2, and an input operation unit 5. An opening is formed in the front part of the housing 2. The cover 3 is attached to the housing 2 so as to close the opening of the housing 2 and is openable and closable.

[0014] The original document conveying unit 4 has an original document feed tray for setting an original document and a plurality of rollers. The original document set on the original document feed tray of the original document conveying unit 4 is conveyed one by one to the reading position of the image reading unit by the plurality of rollers. The image reading unit reads the image of the original document conveyed by the original document conveying unit or the original document placed on the original document table and generates an image signal.

[0015] The input operation unit 5 is configured such that the display unit and the operation unit are integrated. As the display unit, for example, a display monitor such as a liquid crystal display device (LCD) or an organic ELD (Electro Luminescence Display) is applied. And, as the operation unit, for example, a touch panel is applied. And, the input operation unit 5 is configured by laminating and integrating the touch panel applied as the operation unit and the flat panel display applied as the display unit.

[0016] Also, as shown in FIG. 2, the image forming apparatus 1 includes a paper storage unit 20, an image forming unit 40, an intermediate transfer belt 50, a secondary transfer unit 70, and a fixing unit 80. The paper storage unit 20, the image forming unit 40, the intermediate transfer belt 50, the secondary transfer unit 70, and the fixing unit 80 are housed in the housing 2.

[0017] The paper storage unit 20 is disposed at the lower part of the housing 2, and a plurality of them are provided according to the size of the paper which is an example of the recording medium. This paper is fed by the paper feeding unit 21 and sent to the conveying unit 23, and is conveyed by the conveying unit 23 to the secondary transfer unit 70 which is the transfer position. That is, the conveying unit 23 functions to convey the paper fed from the paper feeding unit 21 to the secondary transfer unit 70, and forms a conveying path for conveying the paper S. Also, a manual feeding unit 22 is provided near the paper storage unit 20. From this manual feeding unit 22, papers of sizes not stored in the paper storage unit 20, tag papers having tags, special papers such as OHP sheets are sent to the transfer position.

[0018] Above the paper storage unit 20, the image forming unit 40 and the intermediate transfer belt 50 are disposed. The image forming unit 40 has four image forming units 40Y, 40M, 40C, 40K in order to form toner images of respective colors of yellow (Y), magenta (M), cyan (C), and black (Bk).

[0019] The first image forming unit 40Y forms a yellow toner image, and the second image forming unit 40M forms a magenta toner image. Also, the third image forming unit 40C forms a cyan toner image, and the fourth image forming unit 40K forms a black toner image. Since these four image forming units 40Y, 40M, 40C, and 40K have the same configuration, the first image forming unit 40Y will be described here.

[0020] The first image forming unit 40Y includes a drum-shaped photoreceptor 41 as an image carrier, a charging unit disposed around the photoreceptor 41, an exposure unit 43, a developing unit 44, and a cleaning unit. The photoreceptor 41 rotates counterclockwise by a driving motor (not shown). The charging unit applies charges to the photoreceptor 41 to uniformly charge the surface of the photoreceptor 41. The exposure unit 43 performs exposure scanning on the surface of the photoreceptor 41 based on the image data read from the original document to form an electrostatic latent image on the photoreceptor 41.

[0021] The developing unit 44 attaches yellow toner to the electrostatic latent image formed on the photoreceptor 41, which is an image carrier. As a result, a yellow toner image is formed on the surface of the photoreceptor 41. Note that the developing unit 44 of the second image forming unit 40M attaches magenta toner to the photoreceptor 41, the developing unit 44 of the third image forming unit 40C attaches cyan toner to the photoreceptor 41, and the developing unit 44 of the fourth image forming unit 40K attaches black toner to the photoreceptor 41.

[0022] The toner attached to the photoreceptor 41 is transferred to an intermediate transfer belt 50, which is an example of an image carrier. The cleaning unit removes the toner remaining on the surface of the photoreceptor 41 after it has been transferred to the intermediate transfer belt 50.

[0023] The intermediate transfer belt 50 is formed in an endless shape and rotates clockwise in a direction opposite to the rotation direction of the photoreceptor 41 by a driving motor (not shown). At positions on the intermediate transfer belt 50 facing the photoreceptors 41 of the respective image forming units 40Y, 40M, 40C, and 40K, a primary transfer portion 51 is provided. By applying a polarity opposite to that of the toner to the intermediate transfer belt 50, the primary transfer portion 51 transfers the toner image formed on the photoreceptor 41 to the intermediate transfer belt 50.

[0024] As the intermediate transfer belt 50 rotates, the toner images formed by the four image forming units 40Y, 40M, 40C, and 40K are sequentially transferred to the surface of the intermediate transfer belt 50. As a result, yellow, magenta, cyan, and black toner images overlap on the intermediate transfer belt 50 to form a color image.

[0025] Near the intermediate transfer belt 50 and downstream of the conveyance unit 23, a secondary transfer portion 70 is disposed. The secondary transfer portion 70 is composed of a secondary transfer roller. The secondary transfer portion 70 transfers the color image formed on the intermediate transfer belt 50 onto the paper fed by the conveyance unit 23.

[0026] On the discharge side of the paper in the secondary transfer portion 70, a fixing portion 80 is provided. The fixing portion 80 fixes the toner image transferred to the paper by pressure and heating. The fixing portion 80 has a pair of rollers. In the fixing portion 80, the paper having the unfixed toner image is sandwiched between a pair of rollers and pressure-heated to fix the toner image on the paper.

[0027] Downstream of the fixing portion 80, a switching gate is disposed. The switching gate switches the conveyance path of the paper that has passed through the fixing portion 80. That is, when performing face-up paper discharge in single-sided image formation, the switching gate advances the paper straight. Also, downstream of the switching gate, a paper discharge portion 25 is provided. The paper discharge portion 25 is composed of a pair of rollers. And the paper that has advanced through the switching gate is discharged by the paper discharge portion 25.

[0028] Further, the switching gate guides the paper downward in face-down paper discharge in which the image forming surface in single-sided image formation is directed downward for paper discharge, and guides the paper downward when performing double-sided image formation. When performing face-down paper discharge, after guiding the paper S downward by the switching gate, the front and back sides are reversed and conveyed upward by the paper reversing conveyance unit 26. Thereby, the paper is discharged by the paper discharge unit 25. When performing double-sided image formation, after guiding the paper downward by the switching gate, the front and back sides are reversed by the paper reversing conveyance unit 26, and the paper is sent again to the transfer position through the refeeding path.

[0029] Further, a post-processing device that folds the paper or performs staple processing or the like on the paper may be arranged on the downstream side of the paper discharge unit 25.

[0030] 1-2. Configuration Examples of Movable Unit and Fixed Unit FIG. 3 is a diagram showing the positions of the movable unit 101 and the fixed unit 102 in the image forming apparatus 1. As shown in FIG. 3, the image forming apparatus 1 includes a movable unit 101 and a fixed unit 102. The movable unit 101 and the fixed unit 102 are housed in the housing 2. The movable unit 101 is configured to be pullable out of the housing 2 toward the front side from the opening of the housing 2. The fixed unit 102 is fixed within the housing 2. In this example, the conveyance unit 23, the paper reversing conveyance units 26, the secondary transfer unit 70, and the fixing unit 80 are configured as the movable unit 101. Further, the paper discharge unit 25 is configured as the fixed unit 102.

[0031] FIG. 4 is an enlarged view showing the connection portion between the movable unit 101 and the fixed unit 102. As shown in FIG. 4, the connection portion between the movable unit 101 and the fixed unit 102 is formed across the paper conveyance path 120. That is, the conveyance path of the movable unit 101 and the conveyance path of the fixed unit 102 communicate with each other. Further, as shown in FIG. 4, the fixed unit 102 is provided with a conveyance guide plate 121 that forms the conveyance path 120. In the example shown in FIG. 4, the conveyance guide plate 121 is provided in the fixed unit 102.

[0032] On the downstream side of the conveyance path 120, a roller 131 and a movable roller 132 are arranged. The roller 131 and the movable roller 132 are arranged on the fixed unit 102 side. In this example, the roller 131 and the movable roller 132 are the paper discharge rollers of the paper discharge unit 25. Also, the movable roller 132 rotates even when a jam occurs in the conveyance path 120 and the movable unit 101 is pulled out of the housing 2. Thereby, the paper remaining across the movable unit 101 and the fixed unit 102 is drawn into the movable unit 101 side or the fixed unit 102 side.

[0033] FIG. 5 is a diagram showing an enlarged view of another example of the connection portion between the movable unit 101 and the fixed unit 102. In the example shown in FIG. 5, a roller 125 and a movable roller 126 are arranged on the upstream side of the conveyance path 120, that is, on the movable unit 101 side. Similar to the movable roller 132 shown in FIG. 4, the movable roller 126 rotates when a jam occurs in the conveyance path 120 and the movable unit 101 is pulled out of the housing 2. Thereby, the paper remaining across the movable unit 101 and the fixed unit 102 is drawn into the movable unit 101 side or the fixed unit 102 side. Also, in the example shown in FIG. 5, the conveyance guide plate 121 is configured to be divided into a first guide plate 121a arranged on the movable unit 101 side and a second guide plate 121b arranged on the fixed unit 102 side.

[0034] Next, the detailed configurations of the movable unit 101 and the fixed unit 102 will be described with reference to FIGS. 6 to 8. FIG. 6 is a front view showing a part of the movable unit 101 and the fixed unit 102. FIG. 7 is a perspective view showing a part of the movable unit 101. FIG. 8 is a perspective view showing the fixed unit 102.

[0035] As shown in FIG. 6, the movable unit 101 and the fixed unit 102 are arranged to face each other along the paper conveyance direction. Further, as shown in FIG. 7, the movable unit 101 is configured to be movable in a direction orthogonal to the paper conveyance direction. Hereinafter, the direction in which the movable unit 101 moves is referred to as the extraction direction M1. A rack gear 111 is provided on the opposing surface 101a of the movable unit 101 that faces the fixed unit 102. The teeth constituting the rack gear 111 are formed at a predetermined pitch in the extraction direction M1 of the movable unit 101. This rack gear 111 meshes with a pinion gear 151 provided in the fixed unit 102 described later.

[0036] As shown in FIG. 8, the fixed unit 102 has a side plate 122 orthogonal to the opposing surface 102a that faces the movable unit 101. A movable roller 132 is rotatably supported on the side plate 122. Further, a notch 122a is formed in the vicinity of the movable roller 132 on the side plate 122. Furthermore, the fixed unit 102 is provided with a transmission mechanism 140 and a drive mechanism 150.

[0037] FIG. 9 is a perspective view showing the transmission mechanism 140 and the drive mechanism 150. As shown in FIGS. 8 and 9, the transmission mechanism 140 is arranged on the side plate 122. As shown in FIG. 9, the transmission mechanism 140 has a first pulley 141, a transmission belt 142, and a second pulley 143.

[0038] The first pulley 141 is attached to the shaft end portion of the movable roller 132. Further, a one-way clutch bearing is provided between the first pulley 141 and the shaft end portion of the movable roller 132. The movable roller 132 and the first pulley 141 are rotatably supported by the one-way clutch bearing.

[0039] The one-way clutch bearing transmits the rotational force of the movable roller 132 to the first pulley 141 and does not transmit the rotational force of the first pulley 141 to the movable roller 132. Therefore, during normal operation when the image forming apparatus 1 performs an image forming operation, even if the movable roller 132 rotates, the first pulley 141 does not rotate. On the other hand, when the drive mechanism 150 described later drives and the first pulley 141 rotates, the rotational force of the first pulley 141 is transmitted to the movable roller 132 via the one-way clutch bearing. As a result, the movable roller 132 rotates, and the paper sandwiched between the movable roller 132 and the roller 131 is conveyed in a predetermined direction.

[0040] A transmission belt 142 is wound around the first pulley 141. The transmission belt 142 is formed in an endless shape with both longitudinal ends connected. The transmission belt 142 is wound around the second pulley 143. The second pulley 143 is connected to a second gear 154 of the drive mechanism 150 described later. And when the second gear 154 rotates, the second pulley 143 rotates together with the second gear 154. Also, the rotational force of the second pulley 143 is transmitted to the first pulley 141 via the transmission belt 142. Therefore, when the second pulley 143 rotates, the first pulley 141 also rotates.

[0041] Next, the drive mechanism 150 will be described. As shown in FIG. 9, the drive mechanism 150 includes a pinion gear 151, a drive gear 152, a first gear 153, and a second gear 154. The pinion gear 151 meshes with a rack gear 111 provided on the movable unit 101. Also, the rotation axis of the pinion gear 151 is parallel to the direction in which the movable unit 101 and the fixed unit 102 face each other and is orthogonal to the pulling-out direction M1 of the movable unit 101. A drive gear 152 is connected to the rotation axis of the pinion gear 151. Therefore, when the pinion gear 151 rotates, the driving force is transmitted to the drive gear 152, and the drive gear 152 also rotates.

[0042] The drive gear 152 meshes with the first gear 153, and the first gear 153 meshes with the second gear 154. Therefore, when the drive gear 152 rotates, the first gear 153 and the second gear 154 also rotate. Note that a part of the first gear 153 and the second gear 154 are composed of bevel gears. And the first gear 153 and the second gear 154 convert the direction of the driving force from the drive gear 152.

[0043] Here, when the movable unit 101 is pulled out along the pulling-out direction M1 from the housing 2, the pinion gear 151 of the drive mechanism 150 that meshes with the rack gear 111 provided on the movable unit 101 rotates. And when the pinion gear 151 rotates, the drive gear 152, the first gear 153, and the second gear 154 of the drive mechanism 150 also rotate. Also, when the second gear 154 rotates, the second pulley 143 of the transmission mechanism 140 rotates.

[0044] The rotational force of the second pulley 143 is transmitted to the first pulley 141 via the transmission belt 142, and the first pulley 141 rotates. And when the first pulley 141 rotates, the movable roller 132 rotates via the one-way clutch bearing. Therefore, the paper sandwiched between the movable roller 132 and the roller 131 is fed toward the fixed unit 102 along the conveyance direction. That is, according to the image forming apparatus 1 of this example, the movable roller 132 rotates by the force of pulling out the movable unit 101.

[0045] In this way, when the movable unit 101 is pulled out from the housing 2, by the rotation of the movable roller 132, the paper straddling the movable unit 101 and the fixed unit 102 can be retracted to the fixed unit 102.

[0046] Further, according to the image forming apparatus 1 of this example, a force is applied to the drive mechanism 150 when the movable unit 101 is pulled out of the housing 2. Therefore, since no load is always applied to the drive mechanism 150, the transmission mechanism 140, and the rack gear 111, not only can the component life be extended, but also the operation stability can be achieved. As a result, when a jam occurs, when the movable unit 101 is pulled out of the housing 2, the paper can be surely retracted to the fixing unit 102.

[0047] Furthermore, according to the image forming apparatus 1 of this example, as a force for rotating the movable roller 132 when a jam occurs, the force for pulling out the movable unit 101 from the housing 2 is used. Thereby, it is not necessary to previously install in the housing 2 a driving force for moving the movable roller 132 when a jam occurs, and the number of components can be reduced.

[0048] 2. Second Embodiment Example Next, an image forming apparatus according to a second embodiment example will be described with reference to FIGS. 10 to 15. FIG. 10 is a perspective view showing a fixing unit according to the second embodiment example, and FIG. 11 is a front view showing a transmission mechanism and a drive mechanism according to the second embodiment example. FIG. 12 is a perspective view showing a drive mechanism and a movable roller. FIG. 13 is a perspective view showing a drive mechanism. FIGS. 14 and 15 are front views showing a state where the driving force is released and a connected state.

[0049] The difference between the image forming apparatus according to this second embodiment example and the image forming apparatus 1 according to the first embodiment example lies in the configuration of the transmission mechanism and the drive mechanism. Therefore, here, the same reference numerals are given to the parts common to the image forming apparatus 1 according to the first embodiment example, and the overlapping description is omitted.

[0050] As shown in FIG. 10, the fixed unit 102 is provided with a transmission mechanism 140B and a drive mechanism 150B. The transmission mechanism 140B includes a first pulley 141B, a transmission belt 142, and a second pulley 143. As shown in FIGS. 10 and 12, the first pulley 141B is attached to the axial end of the movable roller 132. A one-way clutch bearing is not provided between the first pulley 141B according to the second embodiment and the axial end of the movable roller 132. Therefore, when the movable roller 132 rotates, the first pulley 141B also rotates, and when the first pulley 141B rotates, the movable roller 132 also rotates. Since the configuration of the other transmission mechanism 140B is the same as that of the transmission mechanism 140 according to the first embodiment, the description thereof is omitted.

[0051] As shown in FIGS. 11 to 13, the drive mechanism 150B includes a pinion gear 151B, a drive gear 152, a first gear 153, a second gear 154, and a third gear 157. Since the configurations of the first gear 153 and the second gear 154 are the same as those of the first gear 153 and the second gear 154 according to the first embodiment, the description thereof is omitted.

[0052] In the drive mechanism 150B according to the second embodiment, a third gear 157 is provided between the drive gear 152 and the first gear 153. The third gear 157 meshes with the drive gear 152 and the first gear 153. The third gear 157 rotates when the drive gear 152 or the first gear 153 rotates. By this third gear 157, the drive mechanism 150B according to the second embodiment can increase the gear ratio more than the drive mechanism 150 according to the first embodiment.

[0053] As shown in FIGS. 14 and 15, a pin 152b is provided on the rotation shaft 152a of the drive gear 152. Further, the rotation shaft of the pinion gear 151B is formed in a cylindrical shape. The rotation shaft 152a of the drive gear 152 is inserted into the cylindrical hole of the rotation shaft of the pinion gear 151B. And the pinion gear 151B is rotatably supported by the rotation shaft 152a of the drive gear 152. During normal image forming operation, even if the drive gear 152 rotates, the pinion gear 151B does not rotate. Further, an engaging portion 151a is formed at the axial end portion of the drive shaft of the pinion gear 151B.

[0054] Further, a connecting portion 162 and a biasing member 163 composed of a coil spring are provided on the rotation shaft 152a of the drive gear 152. The connecting portion 162 is slidably supported by the rotation shaft 152a. The connecting portion 162 has a contact portion 162a, a cylindrical portion 162b, and an engagement receiving portion 162d. The contact portion 162a is formed in a substantially disk shape. An opening through which the rotation shaft 152a passes is formed at the center in the radial direction of the contact portion 162a. A cylindrical portion 162b is formed at one end portion of the contact portion 162a.

[0055] The cylindrical portion 162b is formed in a cylindrical shape. The rotation shaft 152a passes through the cylindrical hole of the cylindrical portion 162b. Further, an opening 162c is formed on the outer peripheral surface of the cylindrical portion 162b. The opening 162c is a long hole extending along the axial direction of the cylindrical portion 162b. The pin 152b provided on the rotation shaft 152a is inserted into the opening 162c. By the pin 152b coming into contact with the opening 162c, the connecting portion 162 rotates together with the drive gear 152.

[0056] On the other bearing portion on the side of the contact portion 162a opposite to the cylindrical portion 162b, an engagement receiving portion 162d is formed. The engagement receiving portion 162d faces the engagement portion 151a of the pinion gear 151B along the axial direction of the rotation shaft 152a of the drive gear 152. As shown in FIG. 14, during normal image forming operation, a connection release member 161 is interposed between the engagement receiving portion 162d and the engagement portion 151a. Therefore, during normal times, the engagement between the engagement receiving portion 162d and the engagement portion 151a is released by the connection release member 161.

[0057] Also, a biasing member 163 is interposed between the contact portion 162a and the drive gear 152. One end of the biasing member 163 abuts on the drive gear 152, and the other end of the biasing member 163 abuts on the contact portion 162a. The biasing member 163 biases the connecting portion 162 in a direction approaching the pinion gear 151B along the axial direction of the rotation shaft 152a.

[0058] Here, the connection release member 161 is attached to a cover 3 (see FIG. 1) that closes the opening of the housing 2. When the cover 3 is opened, the connection release member 161 moves together with the cover 3. Therefore, as shown in FIG. 15, the connection release member 161 retracts from between the engagement receiving portion 162d of the connecting portion 162 and the engagement portion 151a of the pinion gear 151B. When the connection release member 161 retracts, the connecting portion 162 is biased by the biasing member 163 and slides in a direction approaching the pinion gear 151B along the axial direction of the rotation shaft 152a. As a result, the engagement receiving portion 162d of the connecting portion 162 and the engagement portion 151a of the pinion gear 151B engage with each other.

[0059] When the engagement receiving portion 162d and the engagement portion 151a engage with each other, the connecting portion 162 and the pinion gear 151B are integrally connected. As described above, the connecting portion 162 rotates together with the drive gear 152. Therefore, the rotational force of the pinion gear 151B can be transmitted to the drive gear 152, and when the pinion gear 151B rotates, the drive gear 152 also rotates.

[0060] Here, when the movable unit 101 is pulled out along the pulling direction M1 from the housing 2, the pinion gear 151B of the drive mechanism 150B that meshes with the rack gear 111 provided on the movable unit 101 rotates. As described above, when the movable unit 101 is pulled out, since the cover 3 is opened, the connection release member 161 has retreated from between the engagement receiving portion 162d of the connection portion 162 and the engagement portion 151a of the pinion gear 151B. Therefore, the drive gear 152 is connected to the pinion gear 151B via the connection portion 162. As a result, the drive gear 152 and the pinion gear 151B rotate integrally.

[0061] When the drive gear 152 rotates, the third gear 157, the first gear 153, and the second gear 154 also rotate. Further, when the second gear 154 rotates, the second pulley 143 of the transmission mechanism 140B rotates. The rotational force of the second pulley 143 is transmitted to the first pulley 141B via the transmission belt 142, and the first pulley 141B rotates. Then, when the first pulley 141B rotates, the movable roller 132 rotates.

[0062] Also, the drive mechanism 150B according to the second embodiment newly provides a third gear 157 with respect to the drive mechanism 150 according to the first embodiment. Therefore, the rotational direction of the movable roller 132 is opposite to that of the image forming apparatus 1 according to the first embodiment. Therefore, the sheet S1 sandwiched between the movable roller 132 and the roller 131 is fed toward the movable unit 101 in a direction opposite to the conveyance direction.

[0063] That is, also in the image forming apparatus according to this second embodiment, the movable roller 132 can be rotated by the force of pulling out the movable unit 101. In this way, when the movable unit 101 is pulled out from the housing 2, the rotation of the movable roller 132 enables the sheet S1 straddling the movable unit 101 and the fixed unit 102 to be retracted to the movable unit 101.

[0064] In the image forming apparatus according to the second exemplary embodiment, an example in which the sheet is drawn toward the movable unit 101 in the direction opposite to the conveyance direction has been described, but the present invention is not limited thereto. For example, the third gear 157 may be eliminated from the drive mechanism 150B. As a result, when the movable unit 101 is pulled out, the feeding direction of the sheet S1 becomes the same as the conveyance direction. As a result, the sheet S1 is fed toward the fixed unit 102 side.

[0065] Other configurations are the same as those of the image forming apparatus 1 according to the first exemplary embodiment, and thus the description thereof will be omitted. Also with the image forming apparatus according to the second exemplary embodiment, the same operational effects as those of the image forming apparatus 1 according to the first exemplary embodiment described above can be obtained.

[0066] 3. Feed Amount of Recording Medium (Sheet) Next, the feed amount of the sheet in the image forming apparatus having the above-described configuration will be described with reference to FIGS. 16 to 18. FIG. 16 is a diagram showing the clamping position of the movable roller 132, FIG. 17 is a diagram showing the cutting position of the side plate 122, and FIG. 18 is a diagram showing the clamping position of the movable roller 132 and the cutting position of the side plate 122.

[0067] As shown in FIGS. 16 to 18, the movable roller 132 is disposed opposite to the roller 131. The position where the movable roller 132 and the roller 131 come into contact is the clamping position P1 that clamps the sheet S1. When the movable unit 101 is pulled out from the housing 2 and the sheet S1 is retracted to the movable unit 101 side or the fixed unit 102 side, it is necessary to convey the end of the sheet S1 to the clamping position P1.

[0068] When retracting the sheet S1 along the conveyance direction as in the image forming apparatus 1 according to the first exemplary embodiment, the trailing end portion of the sheet S1 in the conveyance direction is moved to the clamping position P1. On the other hand, when retracting the sheet S1 in a direction opposite to the conveyance direction as in the image forming apparatus according to the second exemplary embodiment, the leading end portion of the sheet S1 in the conveyance direction is moved to the clamping position P1. Then, the gear ratios of the various gears constituting the drive mechanisms 150 and 150B are set to gear ratios that can convey the trailing end portion or the leading end portion of the sheet S1 to the clamping position P1.

[0069] Here, when retracting the sheet S1 to the movable unit 101 in a direction opposite to the conveyance direction, the sheet S1 moves in the pulling-out direction M1 together with the movable unit 101. At that time, the sheet S1 may come into contact with the side plate 122. In contrast, a notch 122a is formed in the side plate 122. Also, the terminal position on the downstream side in the conveyance direction in the notch 122a is located on the downstream side in the conveyance direction from the clamping position P1 between the movable roller 132 and the roller 131.

[0070] Therefore, when the sheet S1 is pulled out of the housing 2 together with the movable unit 101, the sheet S1 passes through the notch 122a. Thereby, it is possible to prevent the sheet S1 from contacting the side plate 122 and causing paper jams or paper breakage.

[0071] 4. Feeding (Pulling-in Direction) of the Recording Medium (Sheet) Next, the pattern of the feeding (pulling-in direction) of the sheet in the image forming apparatus 1 having the above-described configuration will be described with reference to FIG. 19. FIG. 19 is a pattern matrix diagram showing the pulling-in direction of the recording medium.

[0072] Pattern A shown in Fig. 19 is a pattern in which the rack gear 111 is installed in the movable unit 101, and the drive mechanism and the movable roller are installed in the fixed unit 102. This pattern A corresponds to the image forming apparatus 1 according to the first embodiment described above. In addition, in the image forming apparatus according to the second embodiment, if the third gear 157 is eliminated, it corresponds to pattern A. The drawing-in direction of the paper S1 in this pattern A is the side of the fixed unit 102 in the same direction as the conveyance direction.

[0073] Pattern B is a pattern in which the rack gear 111 is installed in the fixed unit 102, and the drive mechanism and the movable roller are installed in the movable unit 101. This pattern B corresponds to the example shown in Fig. 5 described above. The drawing-in direction of the paper S1 in this pattern B is the side of the movable unit 101 in the direction opposite to the conveyance direction. As the drive mechanism of this pattern B, the drive mechanism 150B according to the second embodiment is applied.

[0074] Also, pattern C is a pattern in which, similar to pattern B, the rack gear 111 is installed in the fixed unit 102, and the drive mechanism and the movable roller are installed in the movable unit 101. The drawing-in direction of the paper S1 in this pattern B is the side of the fixed unit 102 in the same direction as the conveyance direction. As the drive mechanism of pattern C, the drive mechanism 150 according to the first embodiment is applied. Or, a drive mechanism obtained by eliminating the third gear 157 from the drive mechanism 150B according to the second embodiment may be applied.

[0075] And pattern D is a pattern in which, similar to pattern A, the rack gear 111 is installed in the movable unit 101, and the drive mechanism and the movable roller are installed in the fixed unit 102. This pattern D corresponds to the image forming apparatus according to the second embodiment described above. The drawing-in direction of the paper S1 in this pattern D is the side of the movable unit 101 in the direction opposite to the conveyance direction.

[0076] Thus, the drawing-in direction of the paper S1 can be appropriately set according to the locations where the rack gear 111, the movable roller, and the drive mechanism are installed.

[0077] Above, the embodiments of the image forming apparatus have been described including their operations and effects. However, the image forming apparatus of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the invention described in the claims.

[0078] In the above-described embodiment, a configuration is adopted in which four sets of image forming units 40Y, 40M, 40C, and 40K are used to form a color image. However, as the image forming apparatus according to the present invention, a configuration in which a single image forming unit is used to form a monochrome image may also be adopted. Further, the image forming apparatus is not limited to a copying machine, and may be a printer, a facsimile machine, or a multifunction machine having a plurality of functions.

[0079] In this specification, words such as "parallel" and "orthogonal" are used, but these do not mean only strict "parallel" and "orthogonal", and may be in a state of "substantially parallel" or "substantially orthogonal" that includes "parallel" and "orthogonal" and is within a range in which their functions can be exhibited.

Explanation of Reference Numerals

[0080] 1…Image forming apparatus, 2…Housing, 3…Cover, 20…Paper storage unit, 21…Paper feeding unit, 22…Manual feeding unit, 23…Conveying unit, 25…Paper discharging unit, 26…Paper reverse conveying unit, 40…Image forming unit, 50…Intermediate transfer belt, 51…Primary transfer unit, 70…Secondary transfer unit, 80…Fixing unit, 101…Movable unit, 101a…Opposing surface, 102…Fixed unit, 102a…Opposing surface, 111…Rack gear, 120…Conveying path, 121…Conveying guide plate, 122…Side plate, 125, 131…Roller, 126, 132…Movable roller, 140, 140B…Transmission mechanism, 141, 141B…First pulley, 142…Transmission belt, 143…Second pulley, 150, 150B…Drive mechanism, 150B…Drive mechanism, 151, 151B…Pinion gear, 151a…Engaging portion, 152…Drive gear, 152a…Rotating shaft, 152b…Pin, 153…First gear, 154…Second gear, 157…Third gear, 161…Connection release member, 162…Connection portion, 162a…Contact portion, 162b…Cylindrical portion, 162c…Opening, 162d…Engagement receiving portion, 163…Biasing member, M1…Pull-out direction, P1…Clamping position, S1…Paper (recording medium)

Claims

1. A housing, a fixed unit fixed to the housing and having a conveyance path for conveying a recording medium, a movable unit removably accommodated in the housing and having a conveyance path communicating with the conveyance path of the fixed unit, a movable roller provided on one of the fixed unit and the movable unit for conveying the recording medium, a drive mechanism that rotates the movable roller by a force for pulling out the movable unit when the movable unit is pulled out of the housing, and an image forming apparatus including the same.

2. The movable unit and the fixed unit are arranged to face each other along the conveyance direction of the recording medium, a rack gear is provided on a facing surface of one of the fixed unit and the movable unit that faces each other, the drive mechanism is provided on the other of the fixed unit and the movable unit, and the drive mechanism has a pinion gear that meshes with the rack gear. The image forming apparatus according to claim 1.

3. The unit provided with the drive mechanism among the fixed unit and the movable unit has a transmission mechanism that transmits the driving force from the drive mechanism to the movable roller. The image forming apparatus according to claim 2.

4. The transmission mechanism has a pulley provided at an axial end portion of the movable roller, a one-way clutch bearing is provided between the movable roller and the pulley, and the one-way clutch bearing does not transmit the rotational force of the movable roller to the pulley, but transmits the rotational force of the pulley to the movable roller. The image forming apparatus according to claim 3.

5. When the movable unit is pulled out of the housing, the movable roller moves the rear end of the recording medium along the conveyance direction to a clamping position where the movable roller clamps the recording medium. The image forming apparatus according to claim 4.

6. The drive mechanism includes a gear that transmits the driving force from the pinion gear to the transmission mechanism, and a connecting portion that connects the pinion gear and the gear, and a cover provided on the housing is provided with a connection release member that releases the connection between the pinion gear and the gear by the connecting portion. The image forming apparatus according to claim 3.

7. The fixed unit has a side plate orthogonal to a facing surface facing the movable unit, and a notch is formed in the side plate. The image forming apparatus according to claim 1.

8. The end position of the notch formed in the side plate is formed on the downstream side in the conveyance direction from the clamping position where the movable roller clamps the recording medium. The image forming apparatus according to claim 7.

9. When the movable roller pulls out the movable unit from the housing, the rear end of the recording medium moves the recording medium along the conveyance direction to the clamping position where the movable roller clamps the recording medium. The image forming apparatus according to claim 6.

10. The movable roller is disposed on the movable unit side. When the movable unit is pulled out from the housing, the leading end of the recording medium moves the recording medium along the direction opposite to the conveyance direction to the clamping position where the movable roller clamps the recording medium. The image forming apparatus according to claim 8.

11. The movable roller is disposed on the fixed unit side. When the movable unit is pulled out from the housing, the leading end of the recording medium moves the recording medium along the direction opposite to the conveyance direction to the clamping position where the movable roller clamps the recording medium. The image forming apparatus according to claim 8.

Images