Image forming system and image forming apparatus

An image forming system includes an image forming apparatus and a sheet conveyance apparatus attached detachably to the image forming apparatus. A guide guides the sheet conveyance apparatus to be attached to the image forming apparatus, and an urging portion urges a door toward a first position that is opened with respect to an apparatus body of the image forming apparatus in a case where the door is positioned at a second position opened further than the first position. The sheet conveyance apparatus includes a pressing portion to press the door positioned at the first position toward a closed position when the sheet conveyance apparatus is guided to be attached to the image forming apparatus.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a sheet conveyance apparatus for conveying sheets, and an image forming apparatus and an image forming system equipped with the same.

Description of the Related Art

Generally, image forming apparatuses such as printers are provided with a door configured to open a conveyance path through which sheets are conveyed, which is used for sheet jam and for maintenance. Hitherto, a printer having a first door supported in an openable/closable manner with respect to an apparatus body of a printer, and a second door supported in an openable and closable manner with respect to the first door has been proposed (refer to Japanese Patent Application Laid-Open Publication No. 2011-13299). The first door is configured to open a conveyance path that extends in a vertical direction, and the second door is configured to open a conveyance path in the vicinity of a pivot shaft of the first door.

The second door disclosed in the above-described Japanese Patent Application Laid-Open Publication No. 2011-13299 is arranged at a lower portion of the printer, such that if a wide opening angle is ensured for the second door, accessibility to a lever used for opening and closing the second door will be deteriorated. If a small opening angle is set for the second door, space for treating sheet jam formed by opening the second door is narrowed, and the jam processing performance is deteriorated.

SUMMARY OF THE INVENTION

According to an aspect of the present invention, a sheet conveyance apparatus includes an apparatus body including a conveyance portion configured to convey a sheet, a door supported in an openable/closable manner with respect to the apparatus body around a pivot shaft, and configured to pivot to a first position that is opened with respect to the apparatus body and to a second position that is opened further with respect to the apparatus body than the first position, the door being configured to expose the conveyance portion at both the first and second positions, a pivot member pivotably supported with respect to the apparatus body around the pivot shaft, an urging portion provided between the door and the pivot member, and configured to urge the door and the pivot member to approach each other so that the door and the pivot member are pivoted integrally with respect to the apparatus body, and a regulating portion configured to regulate pivoting of the pivot member at a predetermined pivot angle with respect to the apparatus body in a case where the door is positioned at the first position, wherein the door is configured to be retained at the first position in a state where no external force is applied to the door, is pivoted relatively with respect to the pivot member against urging force of the urging portion while the door moves from the first position to the second position, and is urged toward the first position by the urging portion in a case where the door is positioned at the second position.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

Now, a first embodiment will be described with reference to the drawings. In the following description, positional relationships in up and down, right and left and front and rear directions are described based on the image forming apparatus viewed from a front side, that is, from the viewpoint ofFIG. 1.

General Configuration of Printer

A printer201serving as an image forming apparatus according to the present embodiment is a full-color laser beam printer adopting an electrophotographic system. The printer201includes, as illustrated inFIG. 1, a printer body201A serving as an apparatus body, and a reading unit202provided above the printer body201A and reading image data from a document.

The printer body201A includes an image forming portion201B for forming an image on a sheet P, and a fixing unit220configured to fix the image on the sheet P. Between the reading unit202and the printer body201A is formed a discharge space S to which the sheet P is discharged, and a sheet discharge tray223on which the discharged sheet P is supported is provided in the discharge space S. Further, the printer body201A is provided with a plurality of (two, according to the present embodiment) cassette sheet feeding devices230configured to feed sheets P to the image forming portion201B, and a door100supported in an openable/closable manner with respect to the printer body201A. The door100is arranged lower than the image forming portion201B. Each cassette sheet feeding device230includes a cassette1that stores sheets P, a pickup roller8serving as a conveyance portion for conveying sheets P, a feed roller9and a retard roller10that separate and convey the sheets P one by one.

The image forming portion201B is a so-called four-drum full-color image forming portion including a laser scanner210, four process cartridges211, and an intermediate transfer unit201C. The process cartridges form toner images of respective colors, which are yellow (Y), magenta (M), cyan (C) and black (K). The respective process cartridges211include a photosensitive drum212, a charging unit213, a developing unit214, a cleaner not shown, and so on. A toner cartridge215that stores toner of each color is attached in a detachable manner to the printer body201A above the image forming portion201B.

The intermediate transfer unit201C includes an intermediate transfer belt216wound around a drive roller216aand a tension roller216b, and the intermediate transfer belt216is arranged above the four process cartridges211. The intermediate transfer belt216is arranged to contact the photosensitive drum212of the respective process cartridges211and driven to rotate in a counterclockwise direction by the drive roller216athat is driven by a driving unit not shown. The intermediate transfer unit201C includes primary transfer rollers219that contact an inner circumferential surface of the intermediate transfer belt216at positions opposing to respective photosensitive drums212, and a primary transfer portion TP1is formed as a nip portion between the intermediate transfer belt216and the photosensitive drum212. Further, the image forming portion201B includes a secondary transfer roller217that contacts an outer circumferential surface of the intermediate transfer belt216at a position opposed to the drive roller216a. A secondary transfer portion TP2is formed as a nip portion between the secondary transfer roller217and the intermediate transfer belt216where toner image borne on the intermediate transfer belt216is transferred to the sheet P.

In the respective process cartridges211configured as above, an electrostatic latent image is formed on the surface of the photosensitive drum212by a laser scanner210, and toner is supplied from the developing unit214, by which toner images of respective colors charged to negative polarity are formed. The toner images are sequentially transferred at the respective primary transfer portions TP1to the intermediate transfer belt216in multiple layers by applying transfer bias voltage of positive polarity to the primary transfer roller219, and a full-color toner image is formed on the intermediate transfer belt216.

In parallel with the image forming process, the sheet P fed from the cassette sheet feeding device230is conveyed toward a registration roller pair240, and the registration roller pair240corrects skewing of the sheets. The registration roller pair240conveys the sheet P to the secondary transfer portion TP2at a matched timing with a transfer timing of the full-color toner image formed on the intermediate transfer belt216. The toner image borne on the intermediate transfer belt216is secondarily transferred to the sheet P at the secondary transfer portion TP2by having the transfer bias voltage of positive polarity applied to the secondary transfer roller217.

The sheet P to which toner image has been transferred is heated and pressed at the fixing unit220, by which the color image is fixed to the sheet P. The sheet P having the image fixed thereto is discharged through a first sheet discharge roller pair225aor a second sheet discharge roller pair225bto the sheet discharge tray223and supported thereon. If images are to be formed on both sides of the sheet P, the sheet P is passed through the fixing unit220and switched back by a reverse conveyance roller pair222that is capable of rotating in normal and reverse directions. Then, the sheet P is re-conveyed to the secondary transfer portion TP2through a re-conveyance path R, and an image is formed on a rear side thereof.

Opening/Closing Configuration of Door

As illustrated inFIG. 3A, the door100is supported pivotably with respect to the printer body201A around a pivot shaft102C and includes a handle101that a user uses to open and close the door100, and a door cover102constituting an exterior of the printer body201A. The pivot shaft102C is positioned lower than a center position600of the door100in a vertical direction VD, and the handle101is positioned higher than the center position600. The door100may include a lock mechanism for locking the door with respect to the printer body201A in a state where the door100is closed, and the lock mechanism may be configured to enable the lock of the lock mechanism to be unlocked when the user operates the handle101. The door100may be opened to a first position in which the door is opened to a first angle α1with respect to the printer body201A, as illustrated inFIG. 2A, and a second position in which the door is opened to a second angle α2with respect to the printer body201A, as illustrated inFIG. 2B. Preferably, the angle of α1is between 45° and 60° and the angle of α2is between 70° and 90°, and in the present embodiment, α1=60° and α2=80°.

The second angle α2is greater than the first angle α1(α2>α1), and a processing space C2between the door100positioned at the second position and the printer body201A is greater than a processing space C1between the door100positioned at the first position and the printer body201A. Therefore, jamming of sheets can be treated more easily and jam processing performance is improved when the door100is positioned at the second position than at the first position.

Meanwhile, a height H1from a bottom surface260of the printer body201A to the handle101of the door100positioned at the first position is higher than a height H2from the bottom surface260to the handle101of the door100positioned at the second position. Therefore, the user can access the handle101more easily when the door100is positioned at the first position than when it is positioned at the second position, and the user can operate the door100easily by holding the handle101. That is, the accessibility is higher when the door100is positioned at the first position.

As illustrated inFIGS. 3A through 3C, a pivot member110is pivotably supported on the pivot shaft102C, and the pivot member110serving as a pivot member includes a long hole portion111that constitutes a long hole LH extending in an arc shape in a circumferential direction around the pivot shaft102C. A stopper232serving as a projection protruded from the printer body201A is passed through the long hole LH, and pivoting of the pivot member110is restricted by the stopper232being in contact with an end portion111aof the long hole portion111in the circumferential direction. That is, the long hole portion111and the stopper232constitute a regulating portion70that regulates pivoting of the pivot member110at a predetermined pivot angle with respect to the printer body201A. Further, the pivot member110includes a second abutment portion110B that serves as a third contact portion capable of abutting against a first abutment portion102B of the door cover102. The door100is regulated from opening beyond than the second position in a state where the first abutment portion102B abuts against the second abutment portion110B while the pivot member110is in contact with the end portion111aof the long hole portion111.

A coil portion103C of an urging spring103composed of a torsion spring is wound around the pivot shaft102C, wherein a first end103A of the urging spring103is connected to the door cover102of the door100and a second end103B thereof is connected to a hole portion112formed to the pivot member110. As illustrated inFIG. 3C, in a state where the door100is closed with respect to the printer body201A, a first contact portion102A of the door cover102is in contact with a second contact portion110A of the pivot member110. In this state, the urging spring103serving as an urging portion is positioned such that a torsional angle formed by the first end103A and the second end103B is set to angle β1and generates a moment MS1toward a direction in which the torsional angle becomes smaller. That is, the urging spring103urges the door100and the pivot member110so as to approach each other such that the door100and the pivot member110are pivoted integrally with respect to the printer body201A. More specifically, the urging spring103urges the door100and the pivot member110such that the first contact portion102A of the door cover102and the second contact portion110A of the pivot member110approach each other. It is also possible to arrange a buffer material or other members to be intervened between the first contact portion102A and the second contact portion110A. It is noted that the printer body201A, the door100, the pivot member110, the urging spring103and so on constitute a sheet conveyance apparatus and a first sheet conveyance apparatus.

Opening Operation and Retaining Configuration of Door

Next, an opening operation and retaining configuration of the door100will be described. As illustrated inFIGS. 4A and 4B, if the user holds the handle101(refer toFIG. 3A) serving as a handle portion and opens the door100, the pivot member110pivots together with the door100around the pivot shaft102C by the action of the urging spring103. In this state, the first contact portion102A of the door cover102and the second contact portion110A of the pivot member110maintain contact.

If the door100is opened to the first position, the stopper232contacts the end portion111aof the long hole portion111formed on the pivot member110. Thereby, the pivot member110is regulated from pivoting in an opening direction beyond the predetermined pivot angle. In this state, as illustrated inFIG. 4B, a moment MD1generated by own weight of the door100in a direction opening the door100and the moment MS1generated by the urging spring103in a direction closing the door100are applied to the door100. The moment MS1is set greater than the moment MD1(MS1>MD1), and the first and second contact portions102A and110A are in contact, so the door100is retained at the first position. That is, the door100is retained at the first position unless external force is applied, that is, if the user or the like does not touch the door.

FIGS. 5A and 5Billustrate a state in which the door100is opened further by the user from the first position and is positioned at the second position. When the door100moves from the first position to the second position, the stopper232maintains contact with the end portion111aof the long hole portion111formed on the pivot member110, and the pivot member110will not pivot. That is, the pivot member110is regulated from pivoting by the regulating portion70including the stopper232and the long hole portion111in a state where it is positioned at the first and second positions. With respect to the pivot member110maintaining the stopped state, the door100relatively pivots against the urging force of the urging spring103, and the first contact portion102A is separated from the second contact portion110A. Thereby, the torsional angle formed by the first end103A and the second end103B of the urging spring103is β2which is greater than the angle β1(β2>β1). Further, as illustrated inFIG. 5B, the opening angle of the door100is regulated to the second angle α2(refer toFIG. 2) by the first abutment portion102B of the door cover102abutting against the second abutment portion110B of the pivot member110.

In a state where the door100is positioned at the second position, a moment MD2generated by the own weight of the door100in the direction opening the door100and a moment MS2generated by the urging spring103in the direction closing the door100are applied to the door100. The moment MS2is set greater than the moment MD2(MS2>MD2), and the first and second contact portions102A and110A are separated, such that the door100attempts to return to the first position. Therefore, if the user removes his/her hand from the door100, the door100returns to the first position by urging force of the urging spring103.

According to this configuration, even if the user removes his/her hand from the door100, the door100will be retained at the first position, as illustrated inFIG. 2A. Thereby, the height from the bottom surface260of the printer body201A to the handle101will be set to height H1, and the user can easily access the handle101. Therefore, usability can be improved.

As illustrated inFIG. 2B, in a state where the user opens the door100to the second position against the urging force of the urging spring103, a wide processing space C2can be ensured between the door100and the printer body201A, and the jam processing performance can be improved. Thereby, the accessibility to the door100and the jam processing performance can be realized at the same time.

When the user opens the door100from the closed state to the first position, the user must operate the handle101, but once the door100is opened to the first position, the user can push the door100to be opened to the second position without operating the handle101. If the user removes his/her hand from the door100positioned at the second position, the door100is returned to the first position by the urging spring103, and the door100can be closed easily, such that the operation performance of the door100is improved.

External Sheet Conveyance Apparatus

As illustrated inFIGS. 6A and 6B, an external sheet conveyance apparatus300serving as a second conveyance apparatus can be connected detachably to the printer201, and the printer201and the sheet conveyance apparatus300constitute an image forming system400. In order to connect the sheet conveyance apparatus300to the printer201, a guide500is attached to the printer201. The sheet conveyance apparatus300is guided by the guide500from the side of the printer201in which the door100is positioned, moved to the direction of arrow D and connected to the printer201. The sheet conveyance apparatus300includes a housing301and a pressing portion302that protrudes from a side surface301aof the housing301.

As illustrated inFIG. 6A, in a state where the door100is positioned at the first position opened at the first angle α1, the pressing portion302is capable of pressing an upper portion100A of the door100to close the door. That is, the pressing portion302of the sheet conveyance apparatus300can press and close the door100while the sheet conveyance apparatus300is being connected to the printer201. In a state where the door100is positioned at the first position, an angle formed by the arrow D direction indicating the direction of movement of the sheet conveyance apparatus300and a direction R1in which the door100closes is angle γ1.

Meanwhile, as illustrated inFIG. 6B, in a state where the door100is positioned at a second position opened to a second angle α2, the upper portion100A of the door100is positioned below the pressing portion302. Therefore, even if the sheet conveyance apparatus300is moved in the arrow D direction, the pressing portion302will not contact the upper portion100A. In a state where the door100is positioned at the second position, an angle formed by the arrow D direction indicating the direction of movement of the sheet conveyance apparatus300and a direction R2in which the door100closes is angle γ2, which is greater than γ1(γ2>γ1).

As described, as the angle formed by the arrow D direction and the direction R2in which the door closes increases and approximates 90°, it becomes difficult for the sheet conveyance apparatus300to close the door100. According to the present embodiment, even if the door100is opened by the user, it is retained at the first position as illustrated inFIG. 6A, so the door100can be closed by the pressing portion302of the sheet conveyance apparatus300. Therefore, even if the user forgets to close the door100when the user connects the sheet conveyance apparatus300to the printer201, the door100will be closed by the pressing portion302, such the pressing portion302functions as a foolproof portion in case the user forgets to close the door100.

In a state where the door100is positioned at the first position, the angle formed by the arrow D direction and the direction R2in which the door100closes is relatively small, and the door100can be closed easily. Furthermore, the possibility of the sheet conveyance apparatus300colliding strongly against the door100and causing damage to the door100or the sheet conveyance apparatus300can be reduced.

Second Embodiment

Next, a second embodiment of the present invention will be described. Compared to the first embodiment, the second embodiment changes the positional relationship of the stopper, the door and the pivot member, and the urging force of the urging spring. Therefore, the components similar to the first embodiment are either not shown in the drawing or denoted with the same reference numbers.

FIG. 7Ais a side view illustrating a door200and the pivot member110positioned at a third position that is closer to a closed position with respect to the printer body201A (refer toFIG. 2) than the first position. In the third position, the door200is opened to a third angle α3that is smaller than the first angle α1with respect to the printer body201A (α1>α3).FIG. 7Bis a side view illustrating the door200in the first position and the pivot member110, andFIG. 7Cis a side view illustrating the door200in the second position and the pivot member110. That is, as the door200opens, the door200is transited to the third position (position illustrated inFIG. 7A), the first position (position illustrated inFIG. 7B) and the second position in the named order (position illustrated inFIG. 7C).

In a state where the door200is opened to the third position, as illustrated inFIG. 7A, the stopper232contacts the end portion111aof the long hole portion111formed on the pivot member110. Thereby, pivoting movement of the pivot member110to the opening direction is regulated. In this state, a moment MD0generated by the own weight of the door200in a direction opening the door200and a moment MS0generated by the urging spring103in a direction closing the door200are applied to the door200. The moment MD0is set greater than the moment MS0(MD0>MS0), and the door200is pivoted by its own weight toward the first and second positions. In a state where the door200is positioned at the third position, the torsional angle formed by the first end103A and the second end103B of the urging spring103is β0that is smaller than angle β1(β0<β1).

When the door200moves from the third position to the first position, as illustrated inFIG. 7B, the stopper232maintains contact with the end portion111aof the long hole portion111formed on the pivot member110, and the pivot member110does not pivot. With respect to the pivot member110maintaining a stopped state, the door200pivots relatively against the urging force of the urging spring103, and the first contact portion102A separates from the second contact portion110A. Thereby, the torsional angle formed by the first end103A and the second end103B of the urging spring103will be β1, which is greater than angle β0.

In a state where the door200reaches the first position, a moment MD1′ generated by the own weight of the door200in a direction opening the door200and a moment MS1′ generated by the urging spring103in a direction closing the door200are applied to the door200. Moment MS1′ is set to be equal to moment MD1′, and the balance between these moments maintains the door200at the first position.

As illustrated inFIG. 7C, in a state where the door200is further opened by the user from the first position to the second position, the first contact portion102A of the door200separates further from the second contact portion110A of the pivot member110. When the door is positioned at the third position, the first position and the second position, the pivot member110is regulated from pivoting by the regulating portion70including the stopper232and the long hole portion111. Thereby, the torsional angle formed by the first end103A and the second end103B of the urging spring103will be β2, which is greater than angle β1. Further, since the first abutment portion102B of the door cover102abuts against the second abutment portion110B of the pivot member110, an opening angle of the door200is regulated to a second angle α2(refer toFIG. 2).

In a state where the door200is positioned at the second position, a moment MD2generated by the own weight of the door200in a direction opening the door200and a moment MS2generated by the urging spring103in a direction closing the door200are applied to the door200. The moment MS2is set greater than the moment MD2(MS2>MD2), and the first and second contact portions102A and110A are separated, such that the door200attempts to return to the first position. Therefore, if the user removes his/her hand from the door200, the door200returns to the first position by an urging force of the urging spring103.

According to this configuration, similar to the first embodiment, the accessibility to the door200and the jam processing performance can be realized at the same time. Further, as described with respect toFIG. 6, the door200will be closed even if the user forgets to close the door, and damage to the door200and the sheet conveyance apparatus300can be reduced.

According to any of the embodiments described above, the urging spring103is provided between the pivot member110and the door, but the present invention is not restricted thereto. For example, a configuration can be adopted where the urging spring103is provided between the printer body201A (including the stopper232) and the door, and the pivot member110may be omitted. In this state, the urging force of the urging spring103is set to be balanced with the door positioned at the first position.

According to any of the above-described embodiments, the door is supported in an openable/closable manner on the printer body201A, but the present invention is not restricted thereto. For example, a configuration can be adopted where a processing door supported in an openable/closable manner on the printer body201A and capable of opening a re-conveyance path R is provided, and the above-described door (100or200) can be provided in an openable/closable manner to the processing door. Further, the printer body201A should include at least one conveyance portion for conveying the sheets, such as the feed roller9or the retard roller10, instead of the pickup roller8, and configured such that the conveyance portion is exposed if the door is opened.

The above-described embodiments have been described based on the printer201adopting an electrophotographic system, but the present invention is not restricted thereto. For example, the present invention can be applied to an image forming apparatus adopting an ink-jet system that forms images on sheets by injecting ink through nozzles. Moreover, the present invention can be applied to an external sheet conveyance apparatus300or to a finisher that performs various processing such as punching and sorting of sheets.

Other Embodiments

This application claims the benefit of Japanese Patent Application No. 2017-206325, filed on Oct. 25, 2017, which is hereby incorporated by reference herein in its entirety.