Patent Grant
11119439
The present disclosure generally relates to an image forming apparatus, such as a copying machine or a printer, which employs an electrophotographic process, and more particularly, to a lock mechanism for opening or closing a door in jam processing.
An image forming apparatus forms an image on a recording medium by an electrophotographic process. Examples of the image forming apparatus include an electrophotographic copying machine, an electrophotographic printer (e.g., a laser beam printer and a light-emitting diode (LED) printer), a facsimile apparatus, and a word processor.
In an image forming apparatus, such as a printer, which uses an electrophotographic process, an electrophotographic photosensitive member serving as an image bearing member is uniformly charged and a latent image is formed by selectively exposing the surface of the electrophotographic photosensitive member to light. Then, the latent image is developed with developer (toner) to form a toner image (developer image) as a visible image. The toner image is transferred onto a recording medium. There are two types of color image forming apparatuses. More particularly, there is an image forming apparatus of a type that directly transfers a toner image from an image bearing member onto a recording medium, and an image forming apparatus of a type that transfers a toner image onto an intermediate transfer member once and then secondarily transfers the toner image from the intermediate transfer member onto a recording medium. In the latter case, an intermediate transfer belt is often used as the intermediate transfer member, and a secondary transfer roller is strongly urged against the intermediate transfer belt to form a nip. The recording medium is caused to pass through the nip to transfer the toner image onto the recording medium from the intermediate transfer belt. After that, heat and pressure are applied to the transferred toner image to fix and record the toner image on the recording medium.
In the configuration described above, the secondary transfer roller and components surrounding the secondary transfer roller may be integrally formed as a secondary transfer unit to, for example, facilitate the jam processing, and the unit may be rotated around an apparatus main body to expose a conveyance path (Japanese Patent Application Laid-Open No. 2015-163960). In this case, an urging reaction force acting on the intermediate transfer belt is applied to the secondary transfer unit. Therefore, a mechanism for locking the secondary transfer unit in the apparatus main body against the force may be desirably used. It may be desirable to provide a plurality of such lock mechanisms (engaging portions) to distribute the reaction force. On the other hand, in the case of closing the secondary transfer unit, some of the plurality of lock mechanisms cannot be normally locked due to the reaction force applied from the secondary transfer roller or the like. This may cause a malfunction or failure. Accordingly, a configuration is known in which a portion in the vicinity of the center of the lock mechanism is pressed to normally lock the mechanism.
According to the art, in which a mechanism for locking a secondary transfer unit in an apparatus main body and an opening/closing member for covering the secondary transfer unit are provided, there is a need to perform not only locking/unlocking operations for the mechanism for locking the secondary transfer unit in the apparatus main body, but also to perform opening/closing operations for the opening/closing member during jam processing. The present disclosure includes an image forming apparatus with improved usability.
According to an aspect of the present disclosure, an image forming apparatus includes an apparatus main body including an image forming portion, an opening/closing unit provided to be rotatable relative to the apparatus main body and configured to take a first closed position for forming a conveyance path through which a recording material on which an image is formed is conveyed, and a first open position for opening the conveyance path, and an opening/closing member provided to be rotatable relative to the apparatus main body and configured to take a second closed position for covering an opening provided in the apparatus main body that exposes the opening/closing unit to form a double-sided conveyance path, and the second open position for opening the double-sided conveyance path. The opening/closing unit includes an engaging portion configured to engage with a portion of the apparatus main body to be engaged, an interlock shaft configured to be rotatable in conjunction with the engaging portion and to be parallel to a rotation axial direction of the opening/closing unit, and a gripping portion configured to rotate the interlock shaft, the engaging portion engaging with the portion to be engaged to position the opening/closing unit at the first closed position. The opening/closing member includes a protruding portion configured to enable a movement from the closed position to the first open position such that the protruding portion engages with the gripping portion of the opening/closing unit positioned at the first closed position when the opening/closing member moves from the second closed position to the second open position, and rotates the engaging portion through the gripping portion to release the engagement with the portion to be engaged.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
While the present exemplary embodiment described below illustrates a printer as one aspect of the image forming apparatus 100, the present exemplary embodiment is not limited to this example. For example, other types of image forming apparatuses, such as a copying machine and a facsimile apparatus, or a multi-function peripheral including a combination of these functions can be applied as the image forming apparatus 100.
In the following description, a front side (side which faces a user) of the image forming apparatus 100 is a side on which an apparatus opening/closing door (main body door) 31 is provided. A rear side (opposite side from the user) is an opposite side of the front side. A front-rear direction is a rear-to-front direction of the image forming apparatus 100 and a front-to-rear direction (rear direction) of the image forming apparatus 100. The left and right of the image forming apparatus 100 are left and right of the image forming apparatus 100 as seen from the front side of the image forming apparatus 100. A left-right direction is a right-to-left direction (leftward direction) and a direction (rightward direction) opposite to the right-to-left direction. Top and bottom sides are top and bottom sides in the gravity direction. An upward direction is a bottom-to-top direction. A downward direction is a top-to-bottom direction.
A lengthwise direction is a direction which is parallel to a rotation axis of an electrophotographic photosensitive member, which is an image bearing member on which a latent image is to be formed. A widthwise direction is a direction which is perpendicular to the lengthwise direction (perpendicular direction). One of the lengthwise ends of the photosensitive member is referred to as a drive side, and the other one of the lengthwise ends is referred to as a non-drive side. In the present exemplary embodiment, the right end in the lengthwise direction corresponds to the drive side, and the left end in the lengthwise direction corresponds to the non-drive side.
<Overall Configuration of Image Forming Apparatus>
A cartridge accommodating portion 100B is provided within an apparatus main body 100A of the image forming apparatus 100. Four cartridges, i.e., the first to fourth cartridges PY, PM, PC, and PK are arranged from the rear side toward the front side of the apparatus main body 100A in the cartridge accommodating portion 100B, and are each mounted at a predetermined mounting position (inline configuration, tandem type). Each cartridge P is pressed by a pressing unit 42, is fixed to a predetermined positioning portion of the apparatus main body 100A in the cartridge accommodating portion 100B, and is held at the predetermined mounting position. Each cartridge P is mounted at the predetermined mounting position such that a drive output portion of the apparatus main body 100A is coupled to a drive input portion of the cartridge P (not illustrated). As a result, a predetermined driving force can be transmitted to each cartridge P from a drive source of the apparatus main body 100A. Each cartridge P is mounted at the predetermined mounting position such that a power feed system of the apparatus main body 100A can be electrically connected to an electrical contact of each cartridge P and thus a bias necessary for image formation can be supplied, as needed. In the present exemplary embodiment, the mounting position of each cartridge P is a position at which the cartridge P can perform an image formation operation in the cartridge accommodating portion 100B.
Each cartridge P constitutes an image forming portion that forms an image on a recording medium S, and is detachably mounted on the apparatus main body 100A of the image forming apparatus 100. Each cartridge P includes a drum-type electrophotographic photosensitive member (hereinafter referred to as a drum) 1 serving as an image bearing member on which a latent image is to be formed. In the present exemplary embodiment, each cartridge P is a so-called integrated process cartridge that includes not only the drum 1, but also a charging unit 2, a developing unit 3, and a cleaning unit 4, each of which serves as an image formation processing unit acting on the drum 1. The first cartridge PY contains yellow (Y) toner. The second cartridge PM contains magenta (M) toner. The third cartridge PC contains cyan (C) toner. The fourth cartridge PK contains black (K) toner.
In a portion above the cartridges PY, PM, PC, and PK, a laser scanner unit 11 is provided, which is an example of an exposure unit that exposes the surface of the drum 1 of each cartridge P to light to form a latent image. The scanner unit 11 outputs laser light L that is modulated based on image information about each color, and performs scanning and exposure on the surface of the drum 1 of each cartridge P.
In a portion below the cartridges PY, PM, PC, and PK, an intermediate transfer unit 12 serving as a transfer unit (transfer member) is provided. The intermediate transfer unit 12 is opposed to the drum 1 of each cartridge P. A toner image formed on the drum 1 is primarily transferred onto the intermediate transfer unit 12, and then the toner image is secondarily transferred onto the recording medium S. The intermediate transfer unit 12 is disposed such that, for example, the intermediate transfer unit 12 contacts a frame body, which is formed of a sheet metal or the like of the apparatus main body 100A, and is positioned relative to the apparatus main body 100A with high accuracy.
The intermediate transfer unit 12 includes an endless belt 13 serving as an intermediate transfer member, a drive roller 14 that causes the endless belt 13 to move in a circulating manner, a turn roller 15, a tension roller 16, and a belt cleaning portion 12a. The drive roller 14 and the turn roller 15 are provided on the rear side within the apparatus main body 100A. The tension roller 16 is provided on the front side within the apparatus main body 100A. In the present exemplary embodiment, a flexible endless belt made of a dielectric material is used as the endless belt 13. The endless belt 13 is stretched over the drive roller 14, the turn roller 15, and the tension roller 16. The belt cleaning portion 12a is disposed on a downstream side in a conveyance direction of the endless belt 13 at a secondary transfer nip, which is described below, to be urged against the drive roller 14 through the endless belt 13.
A lower surface of each drum 1 contacts an upper surface of an upper-side belt portion of the endless belt 13 in a state where each cartridge P is mounted at the predetermined mounting position. On the inside of the endless belt 13, four primary transfer rollers 17 are provided to face the drums 1 of the cartridges P, respectively, via the upper-side belt portion. In each cartridge P, a nip portion between each drum 1 and the endless belt 13 corresponds to a primary transfer nip portion.
A secondary transfer roller 22 contacts the drive roller 14 of the intermediate transfer unit 12 via the endless belt 13. A nip portion between the secondary transfer roller 22 and the endless belt 13 corresponds to a secondary transfer nip portion.
In a portion below the intermediate transfer unit 12, a sheet feed unit 18 is provided that stores sheet-like recording media (sheet material) S onto which a toner image is to be transferred, and conveys the recording media S one by one to the intermediate transfer unit 12. The sheet feed unit 18 includes a sheet feed tray 19 on which the recording media S are stacked and accommodated, a sheet feed roller 20, a separation roller pair 21, and a registration roller pair 20a. The sheet feed tray 19 can be freely loaded from the front side of the apparatus main body 100A (front loading).
At an upper portion on the rear side in the apparatus main body 100A, a fixing device 23, a discharge roller pair 24, and a reverse roller pair 73 are provided. The fixing device 23 serves as a fixing unit that applies heat and pressure to each recording medium S onto which the toner image is transferred to fix the toner image on the recording medium S. The fixing device 23 includes a fixing film assembly 23a and a pressure roller 23b. The fixing film assembly 23a and the pressure roller 23b form a fixing nip N. With respect to the fixing nip N, on the side opposite to the secondary transfer nip, a reversing flapper 75 for switching a conveyance path between a single-sided printing conveyance path and a double-sided printing conveyance path is rotatably disposed. A drive mechanism (not illustrate) enables the reversing flapper 75 to move from a single-sided printing position to a double-sided printing position, thereby guiding the recording medium S to each of the single-sided printing conveyance path and the double-sided printing conveyance path. The single-sided printing conveyance path is provided to extend toward the discharge roller pair 24. The discharge roller pair 24 includes a discharge roller 24a and a discharge roller 24b. With respect to the discharge roller pair 24, on the opposite side of the single-sided printing conveyance path, a discharge tray 25 is provided on an upper surface of the apparatus main body 100A.
The double-sided printing conveyance path is provided to extend toward the reverse roller pair 73. The reverse roller pair 73 includes a reverse roller 73a and a reverse roller 73b. In single-sided printing, the discharge roller pair 24 discharges the recording medium S onto the discharge tray 25. In double-sided printing, the reverse roller pair 73 conveys the recording medium S toward the discharge tray 25, reverses the rotation direction of the reverse roller pair 73 and conveys the recording medium S to a double-sided unit 70.
The double-sided unit 70 is disposed on the main body rear side of a secondary transfer unit 80. The double-sided unit 70 includes a double-sided roller pair 72 and a sheet refeed roller pair 74 in order from the upstream side in the conveyance direction of the recording medium S. The double-sided roller pair 72 includes a double-sided roller 72a and a double-sided roller 72b. The sheet refeed roller pair 74 includes a sheet refeed roller 74a and a sheet refeed roller 74b. The double-sided roller pair 72 is configured to nip the recording medium S fed from the reverse roller pair 73 and to convey the recording medium S to the sheet refeed roller pair 74. The sheet refeed roller pair 74 is configured to nip the recording medium S fed from the double-sided roller pair 72 and to convey the recording medium to the registration roller pair 20a.
<Image Formation Operation>
An operation for forming a full-color image is described below. The drum 1 of each of the first to fourth cartridges PY, PM, PC, and PK is rotationally driven at a predetermined control speed in a counterclockwise direction indicated by an arrow in
In synchronization with this driving operation, the charging unit 2 uniformly charges the surface of the drum 1 with a predetermined polarity and potential at a predetermined control timing in each cartridge P. The scanner unit 11 performs scanning and exposure on the surface of each drum 1 with the laser light L that is modulated based on the image signal for each color. As a result, an electrostatic latent image corresponding to the image signal for the corresponding color is formed on the surface of each drum 1. The developing unit 3 develops the formed latent image into a toner image with the developer (toner) contained in a container.
In the electrophotographic image formation process operation described above, a Y-color toner image corresponding to a Y-color component of the full-color image is formed on the drum 1 of the first cartridge PY. The toner image is primarily transferred onto the endless belt 13 at a primary transfer nip portion T1 of the cartridge PY.
An M-color toner image corresponding to an M-color component of the full-color image is formed on the drum 1 of the second cartridge PM. The M-color toner image is superimposed on the Y-color toner image, which is already transferred onto the endless belt 13 at the primary transfer nip portion T1 of the second cartridge PM, and then primarily transferred onto the endless belt 13.
A C-color toner image corresponding to a C-color component of the full-color image is formed on the drum 1 of the second cartridge PM. The C-color toner image is superimposed on the (Y+M)-color toner image, which is already transferred onto the endless belt 13 at the primary transfer nip portion T1 of the third cartridge PC, and then primarily transferred onto the endless belt 13.
A K-color toner image corresponding to a K-color component of the full-color image is formed on the drum 1 of the fourth cartridge PK. The K-color toner image is superimposed on the (Y+M+C)-color toner image, which is already transferred onto the endless belt 13 at the primary transfer nip portion T1 of the second cartridge PM, and then primarily transferred onto the endless belt 13.
Thus, unfixed toner images of four colors, i.e., Y-color+M-color+C-color+K-color, which are sequentially transferred onto the endless belt 13 and superimposed, are formed. In each cartridge P, transfer residual toner that remains on the surface of each drum 1 after the toner image is primarily transferred onto the endless belt 13 is removed by the cleaning unit 4.
A sheet feed motor (not illustrated) is driven at a predetermined control timing. A driving force from the sheet feed motor enables the sheet feed roller 20 and the separation roller pair 21 to separate and feed the recording media S stacked on the sheet feed tray 19 one by one and feed the recording media S to the registration roller pair 20a. Thus, the registration roller pair 20a guides the recording media S into the secondary transfer nip portion. At the secondary transfer nip, a secondary transfer bias for transferring the toner image formed on the endless belt 13 onto each of the recording media S is supplied from a power supply unit (not illustrated). The recording media S are nipped by the endless belt 13 and the secondary transfer roller 22 and are conveyed at a speed corresponding to the conveyance speed of the endless belt 13. As a result, in the process in which the recording media S are nipped and conveyed in the secondary transfer nip portion, the four-color superimposed toner images on the endless belt 13 are sequentially and collectively transferred onto the surface of each of the recording media S.
On the other hand, residual toner that has not been transferred onto the recording media S remains on the endless belt 13 after the toner images are transferred. The cleaning portion 12a slides on the endless belt 13 and removes and collects the residual toner from the surface of the endless belt 13. This prevents the residual toner from being transferred onto the subsequent recording medium S.
Each recording medium S is separated from the surface of the endless belt 13 and guided to the fixing device 23 through the conveyance path, and then heated and pressed at the fixing nip N. Thus, the toner images of the respective colors are mixed and fixed on the recording medium S.
In the configuration according to the present exemplary embodiment, the image forming apparatus 100 is capable of performing double-sided printing. A single-sided printing operation and a double-sided printing operation will be described below.
In the case of single-sided printing (
In the case of double-sided printing (
<Details of Secondary Transfer Unit>
A configuration for positioning the secondary transfer unit 80 (opening/closing unit) in the apparatus main body 100A will be described in detail below.
The secondary transfer unit 80 is held by a secondary transfer unit shaft 80c in such a manner that the secondary transfer unit 80 is rotatable relative to the apparatus main body 100A. In the present exemplary embodiment, the secondary transfer unit shaft 80c is a metal shaft that is attached to a secondary transfer frame 80a, which is made of a sheet metal, and is configured to be inserted into a hole (not illustrated) formed in the apparatus main body 100A and to be rotatable. The secondary transfer frame 80a includes a secondary transfer conveyance guide 80b, which is fixed to the secondary transfer frame 80a, the secondary transfer roller 22, bearings 81, which rotatably hold the shaft of the secondary transfer roller 22, and secondary transfer springs 82 that urge the pair of right and left bearings 81, respectively. The secondary transfer conveyance guide 80b is provided such that the recording medium S is guided at least either before or after the recording medium S passes through the secondary transfer nip. Each of the secondary transfer springs 82 is provided between the secondary transfer frame 80a having rigidity and the corresponding bearing 81, and urges the bearing 81 that is movable in an expansion/contraction direction of the secondary transfer spring 82. Thus, the secondary transfer roller 22 is provided such that the secondary transfer nip portion is formed between the secondary transfer roller 22 and the drive roller 14 (intermediate transfer unit 12) via the endless belt 13.
Further, the secondary transfer unit 80 is provided with a secondary transfer lock mechanism 84. The secondary transfer lock mechanism 84 includes lock engaging portions 84a (a first engaging portion and a second engaging portion) that are rotatable relative to the secondary transfer unit 80. The lock engaging portions 84a respectively engage with the portions to be engaged 100p (a first portion to be engaged and a second portion to be engaged), which are provided in the apparatus main body 100A, thereby regulating the rotation of the secondary transfer unit 80 relative to the apparatus main body 100A. In other words, the secondary transfer unit 80 is configured to take a closed position (first closed position) where the recording material S on which an image is formed is conveyed and a conveyance path including the secondary transfer nip portion is formed, and take an open position (first open position) where the conveyance path is opened.
As described above, since the secondary transfer roller 22 and the drive roller 14 form the secondary transfer nip, the secondary transfer unit 80 may be desirably positioned relative to the intermediate transfer unit 12 with high accuracy. On the other hand, the intermediate transfer unit 12 is positioned relative to the apparatus main body 100A and the drive roller 14 is positioned relative to the apparatus main body 100A. Thus, the secondary transfer unit 80 is positioned relative to the apparatus main body 100A with high accuracy, so that a positional deviation from the intermediate transfer unit 12 can be prevented.
The secondary transfer lock mechanism 84 will be described in detail below.
The lock engaging portions 84a are respectively provided at one end and the other end in the axial direction (rotation axial direction) of the secondary transfer unit shaft 80c, and are coupled with the lock shaft 84b and configured to be integrally movable. The lock shaft 84b is held on the secondary transfer unit 80 in such a manner that the lock shaft 84b is rotatable in the axial direction as the rotational axis. The lock shaft 84b and the lock engaging portions 84a are positioned in any direction perpendicular to the axial direction of the lock shaft 84b. The lock shaft 84b is connected with a lock urging member 85 such that a rotation moment is supplied to the lock shaft 84b. Thus, the lock engaging portions 84a engage with the portions to be engaged 100p, respectively, which are provided in the apparatus main body 100A, by an urging force of the lock urging member 85. In other words, when the lock engaging portions 84a are positioned at positions where the lock engaging portion 84a can engage with the portions to be engaged 100p, the lock engaging portions 84a are configured to engage by a rotational moment and hold the engaging state. On the other hand, the secondary transfer unit 80 is provided with the handle 83 (gripping portion) that is fixed such that the handle 83 can be rotated coaxially with the rotation axis of the lock shaft 84b to release the engagement of the lock engaging portions 84a with the portions to be engaged 100p. Thus, the handle 83 can rotate the lock shaft 84b against the urging force of the lock urging member 85.
As the lock shaft 84b, for example, a metal pipe having high rigidity is used. Accordingly, the lock shaft 84b is not deformed due to a reaction force from the secondary transfer spring 82, and the lock engaging portions 84a can reliably engage with the portions to be engaged 100p. Thus, the secondary transfer unit 80 can be locked relative to the apparatus main body 100A. In addition, the lock shaft 84b has high torsional rigidity, and thus when one of the right and left lock engaging portions 84a moves, the other one of the right and left lock engaging portions 84a synchronously moves without any delay.
A case where the secondary transfer unit 80 is caused to transition from the closed position to the open position relative to the apparatus main body 100A will be described below.
The handle 83 is rotated in a direction indicated by an arrow in
Next, a case will be described where the secondary transfer unit 80 is caused to transition from the open position to the closed position.
In the secondary transfer unit 80 at the open position, the lock engaging portions 84a are integrally rotated with the lock shaft 84b. Accordingly, the lock engaging portions 84a are positioned at the predetermined position due to the urging force of the lock urging member 85. Specifically, the handle 83 contacts the secondary transfer conveyance guide 80b (
When the secondary transfer unit 80 in the open state is gradually closed, the leading end of each of the lock engaging portions 84a contacts the corresponding portion to be engaged 100p. The state is illustrated in
The handle 83 serving as an unlock mechanism as described above is disposed in the vicinity of the lock shaft 84b coaxially with the lock shaft 84b, thereby eliminating the need to provide separate rotational centers and to provide a mechanism for operating the rotational centers in synchronization with each other. Therefore, an excellent space efficiency in arrangement of the handle 83 and the lock shaft 84b is obtained.
A one-sided tightening prevention function using the lock mechanism according to the present exemplary embodiment will be described below.
In the present exemplary embodiment, unit engaging portions (lock engaging portions 84a) are provided on the right and left sides, respectively. Conventionally, in a configuration in which a plurality of engaging portions is positioned at separate positions, a state where any one of the engaging portions cannot be locked may occur due to deformation of the unit, a positional tolerance, or the like when the user presses an end of the unit. If such a phenomenon occurs, it is difficult to discern whether or not the unit is accurately positioned relative to the apparatus main body 100A. If the printing operation is carried out in such a state, a malfunction or failure such as paper jam may occur. However, the configuration according to the present exemplary embodiment can avoid the occurrence of the phenomenon in which “some of a plurality of unit engaging portions cannot be accurately locked (hereinafter referred to as “one-sided tightening”)”, by the right and left lock engaging portions 84a. The lock engaging portions 84a operate interlocking with the lock shaft 84b. The principle of one-sided tightening will be described below.
A substantially central portion of the secondary transfer unit 80 is pressed to cause the secondary transfer unit 80 to move straight into the apparatus main body 100A, thereby making it possible to simultaneously lock the right and left lock engaging portions 84 and to position the secondary transfer unit 80 relative to the apparatus main body 100A. In this case, as illustrated in
On the other hand, as a result of an operation, such as pressing in the vicinity of the right and left ends of the secondary transfer unit 80, the secondary transfer unit 80 may obliquely enter the apparatus main body 100A. In this case, as illustrated in
<Details of Double-Sided Unit>
The double-sided unit 70 (opening/closing member) will be described in detail below.
The double-sided unit 70 includes a double-sided door 71 that is rotatable around a double-sided unit shaft 76 engaging with a hole 100q which is provided in the apparatus main body 100A. The hole 100q is fit to the double-sided unit shaft 76 in the front-rear direction without looseness. The hole 100q is an oval hole having a clearance in the top-bottom direction. The double-sided unit 70, i.e., the double-sided door 71 is positioned in the front-rear direction by the double-sided unit shaft 76 inserted into the hole 100q and is temporarily held with a degree of freedom in the top-bottom direction. Further, the double-sided unit 70 includes a double-sided lock portion 70a and a double-sided engagement shaft 70b.
The double-sided lock portion 70a is rotatably attached to the double-sided door 71 and is urged in a closing direction by a spring (not illustrated). The double-sided lock portion 70a has a hook-shape leading end. The hook shape is positioned by hanging on a portion to be engaged 100r which is provided within the apparatus main body 100A. The double-sided door 71 is locked relative to the apparatus main body 100A at a closed position (second closed position) where a double-sided conveyance path is formed. At the time, the double-sided unit 70, i.e., the double-sided door 71 is positioned at the position where the opening in the apparatus main body 100A through which the secondary transfer unit 80 is exposed is covered. In the present exemplary embodiment, the double-sided lock portion 70a is integrally formed with a double-sided handle 70c that is attached to the double-sided door 71. When the double-sided unit 70 is locked at the closed position of the apparatus main body 100A, the user grips the double-sided handle 70c to rotate the double-sided lock portion 70a. Through the operation, the locked state can be released to enable movement of the double-sided unit 70 to an open position (second open position) where the double-sided conveyance path is opened (
The double-sided engagement shaft 70b is a shaft that extends in parallel to the double-sided unit shaft 76 and engages with a double-sided portion to be engaged 23p which is provided in the fixing unit of the apparatus main body 100A. The double-sided portion to be engaged 23p has a groove shape that is fit to the double-sided engagement shaft 70b in the top-bottom direction of the apparatus main body 100A, and the top-bottom direction of the double-sided unit 70 is positioned relative to the fixing unit 23. In this manner, an upper portion of the double-sided unit 70 is positioned relative to the fixing device 23, which makes it possible to accurately receive and convey the recording media S fed from the fixing device 23.
<Door Opening/Closing Synchronous Operation During Jam Processing>
If a jam of the recording media S has occurred during the image formation operation, the user opens the double-sided unit 70 to take out the recording media S from the apparatus main body 100A, thereby making it possible to access the double-sided printing conveyance path in the apparatus main body 100A to remove the recording media S. Then, the user further opens the secondary transfer unit 80 from the state where the double-sided unit 70 is opened, thereby making it possible to access the conveyance path leading from the registration roller portion to the secondary transfer portion and leading from the secondary transfer portion to the fixing portion to remove the recording media S.
In this case, the user grips and pulls the double-sided handle 70c of the double-sided door 71, which is positioned at the outermost side, thereby making it possible to synchronously rotate the double-sided lock portion 70a to release the locked state and to open the double-sided unit 70. In the present exemplary embodiment, the secondary transfer unit 80 can also be opened synchronously with this operation. This operation will be described in detail below.
(Door Synchronous Opening Operation)
With this configuration, by one operation, the user can access the recording media S jammed in the double-sided conveyance path and in the conveyance path leading from the registration roller portion to the secondary transfer portion and leading from the secondary transfer portion to the fixing portion, which improves apparatus usability.
In particular, in the present exemplary embodiment, the gap C is provided between the lock shaft 84b and the bearing portion 830 of the handle 83 that is rotated to release the engagement of the lock engaging portions 84a with the portions to be engaged 100p.
The hook portion 77 is fixed to the double-sided door 71 constituting the double-sided unit 70, and the double-sided door 71 is fixed with the hook portions 77 in the apparatus main body 100A, thereby forming the double-sided printing conveyance path through which the recording media S pass. When the double-sided unit 70 is positioned at the closed position where the double-sided printing conveyance path is formed in the apparatus main body 100A, the rotational center of the double-sided unit 70 is positioned in the front-rear direction, while the position of the double-sided unit 70 in the top-bottom direction is determined with a degree of freedom. Further, the double-sided unit 70, i.e., the double-sided door 71 can be distorted or deformed. Accordingly, the hook portions 77 integrally formed with the double-sided door 71 are also positioned in the front-rear direction, while the position of each of the hook portions 77 in the top-bottom direction is determined with a degree of freedom. When the double-sided door 71 is opened or closed, the hook portions 77 may be slightly displaced from a predetermined movement locus.
Thus, in a configuration in which the handle 83 does not include the gap C relative to the bearing portion 830 and the handle 83 is integrally formed with the bearing portion 830, when the hook portions 77 are displaced from the predetermined movement locus and the hook portions 77 contact the handle 83, the handle 83 cannot move on the basis of the position of each of the hook portions 77. As a result, there is a possibility that the hook portions 77 cannot fully engage with the handle 83 and the secondary transfer unit 80 cannot be opened synchronously with the opening operation of the double-sided unit 70. There is another possibility that the hook portions 77 may engage with the handle 83 with a strong force and the handle 83 or one of the hook portions 77 may be damaged when the secondary transfer unit 80 is also opened synchronously with the opening operation of the double-sided unit 70.
However, according to the present exemplary embodiment, the gap Cis provided between the lock shaft 84b and the bearing portion 830 of the handle 83, and the handle 83 can be moved by the amount corresponding to the gap C between the bearing portion 830 and the lock shaft 84b in the direction perpendicular to the lock shaft 84b. With this configuration, if the hook portions 77 move in a direction deviating from the predetermined movement locus and contact the handle 83, the handle 83 can be moved on the basis of the position of each of the hook portions 77. More specifically, the orientation of the handle 83 can be changed so that one of the hook portions 77 and the other one of the hook portions 77 sequentially contact the handle 83, thereby bringing the handle 83, and the hook portions 77, which are positioned at one end and the other end respectively, into a predetermined contact state. As a result, the hook portions 77 can engage with the handle 83 with a force within a predetermined range, and the secondary transfer unit 80 can be stably opened synchronously with the opening operation of the double-sided unit 70.
The handle 83 is disposed with the gap C formed relative to the secondary transfer conveyance guide 80b, and the handle 83 is configured to move on the basis of the position of each of the hook portions 77 without interfering with the secondary transfer conveyance guide 80b, so that advantageous effects of the present disclosure can be obtained.
(Synchronous Door Closing Operation)
After finishing the jam processing, the user needs to close the two doors to be ready for image formation. In this case, in the configuration according to the present exemplary embodiment, the secondary transfer unit 80 can also be closed synchronously with the closing operation of the double-sided unit 70. The outline of this operation will be described below.
When the closing operation of the double-sided unit 70 is started, as illustrated in
When the closing operation is further continued to rotate the handle 83 by the predetermined amount or more and the right and left lock engaging portions 84a each reach the predetermined position, the lock engaging portions 84a engage with the portions to be engaged 100p, as illustrated in
In this manner, the secondary transfer unit 80 is moved synchronously with the double-sided unit 70 and is locked and positioned relative to the apparatus main body 100A. However, since the double-sided unit 70 is not locked yet, the user needs to further carry on the closing operation. In this case, the hook portions 77 are deformed and moved while the leading end thereof slides on the portion 832 of the handle 83 to be contacted, so that a part of the handle 83 is positioned between the double-sided door 71 and the hook portions 77 in the left-right direction. On the other hand, the double-sided lock portion 70a engages with the hook portion provided on the fixing unit, thereby positioning the double-sided unit 70 relative to the apparatus main body 100A (
As described above, in the configuration according to the present exemplary embodiment, the user can close the two doors by performing the closing operation once. This leads to an improvement in usability.
In particular, in the present exemplary embodiment, the gap C is provided between the lock shaft 84b and the bearing portion 830 of the handle 83 that is rotated to release the engagement of the lock engaging portions 84a with the portions to be engaged 100p.
In the configuration in which the handle 83 does not include the gap C relative to the bearing portion 830 and the handle 83 is integrally formed with the bearing portion 830, after the hook portions 77 are moved in a direction deviating from the predetermined movement locus and the hook portions 77 contact the handle 83, the handle 83 cannot be moved on the basis of the position of each of the hook portions 77. As a result, the hook contact portion 77b of each hook portion 77 cannot contact the portion 833 of the handle 83 to be engaged. In this case, there is a possibility that the movement of the hook portions 77 may be hindered by the handle 83 and after the secondary transfer unit 80 is closed, the double-sided unit 70 cannot be closed and the handle 83 or one of the hook portions 77 may be damaged.
However, in the present exemplary embodiment, the gap C is provided between the lock shaft 84b and the bearing portion 830 of the handle 83 and the handle 83 can be moved by the amount corresponding to the gap C between the bearing portion 830 and the lock shaft 84b in the direction perpendicular to the lock shaft 84b. In this configuration, if the hook portions 77 are moved in a direction deviating from the predetermined movement locus and contact the handle 83, the handle 83 can be moved on the basis of the position of each of the hook portions 77.
More specifically, the orientation of the handle 83 is changed so that the hook engaging portion 77b of one of the hook portions 77 and the hook engaging portion 77b of the other one of the hook portions 77 sequentially contact the portion 833 of the handle 83 to be engaged. As a result, the hook engaging portion 77b of one of the hook portions 77 and the portion 833 of the handle 83 to be engaged, or the hook engaging portion 77b of the other one of the hook portions 77 and the portion to be engaged 833 of the handle 83 are brought into the predetermined contact state. As a result, the hook engaging portion 77b of each hook portion 77 can reliably contact the portion to be engaged 833 of the handle 83 and the double-sided unit 70 can be closed after the secondary transfer unit 80 is closed.
The handle 83 is disposed making the gap C relative to the secondary transfer conveyance guide 80b, and the handle 83 is configured to move on the basis of the position of each of the hook portions 77 without interfering with the secondary transfer conveyance guide 80b, so that advantageous effects of the present disclosure can be obtained.
A relationship between the hook portions 77 and the handle 83 in the closing operation process will be described in more detail below.
In the closing operation process, as described above, the hook portions 77 can provide a pressing force large enough to move the right and left lock engaging portions 84a to a predetermined position relative to the handle 83 so as to position the secondary transfer unit 80 relative to the apparatus main body 100A. A load to be applied in this case is represented by F1. A pressing force to be applied when the hook portions 77 are deformed to penetrate through the handle 83 and engage with the handle 83 to lock the double-sided unit 70 relative to the apparatus main body 100A is represented by F2.
When the double-sided unit 70 is closed, F1<F2 needs be desirably satisfied so that the secondary transfer unit 80 can be accurately locked relative to the apparatus main body 100A. In this case, the hook portions 77 each have a cantilever shape. Accordingly, the smaller the pressing force F2 required for deformation as a hitching amount between the hook portions 77 and handle 83, and the more the pressing force F2, the higher the hitching amount becomes. Further, the hitching amount can vary depending on a dimensional tolerance of each component and right and left gaps. Accordingly, it may be desirable to set a design nominal value for F2 to satisfy F1<F2 if the above-described variable factors are taken into consideration. On the other hand, since the pressing force F2 is a force to be applied when the user closes the double-sided unit 70, the pressing force F2 may be desirably set to a smaller value in terms of usability.
In the configuration according to the present exemplary embodiment, two claws of the hook portions 77 facing each other are used. Accordingly, even when the positions of the hook portions 77 and the handle 83 are deviated in the rotation axial direction as illustrated in
Further, since the secondary transfer unit 80 is positioned relative to the image forming apparatus main body 100A in the top-bottom direction, and the double-sided unit 70 is positioned relative to the fixing unit in the top-bottom direction, so that the hook portions 77 and the handle 83 may be inclined to each other.
As described above, the configuration according to the present exemplary embodiment makes it possible to suppress a variation in the hitching amount of the hook portions 77 with respect to the positional deviation in the rotation axial direction, and the mutual inclination. Consequently, the design nominal value for F2 can be set to a smaller value, and thus an improvement in usability can be achieved.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of priority from Japanese Patent Applications No. 2019-140183, filed Jul. 30, 2019, and No. 2019-140184, filed Jul. 30, 2019, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2019-140183 | Jul 2019 | JP | national |
| JP2019-140184 | Jul 2019 | JP | national |
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| Number | Date | Country |
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| 2008216595 | Sep 2008 | JP |
| 2009251135 | Oct 2009 | JP |
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| 2012194508 | Oct 2012 | JP |
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| Number | Date | Country | |
|---|---|---|---|
| 20210034009 A1 | Feb 2021 | US |
