JP5148008B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus in which an image carrier unit having an image carrier can be attached and detached by opening and closing an opening / closing member.

  Conventionally, an image forming apparatus detachably provided with an image carrier unit having an image carrier such as a photosensitive drum or an intermediate transfer belt has been provided with an openable / closable opening / closing member. The carrier unit is configured to be detachable. The image carrier is pressed by a transfer member for transferring the developer image carried on the image carrier to a recording medium. However, the image carrier is opened and closed in consideration of a paper jam between the image carrier and the transfer member. When the member is opened, the pressing of the transfer member against the image carrier is released. For example, in Patent Document 1, in a state in which an openable / closable member attached to the main body is opened, the pressure between the image carrier and the transfer member provided in the main body is released, and the image carrier and the transfer member Are disclosed to be spaced apart.

  Further, in Patent Document 2, an openable / closable guide that pivotally supports the transfer member is provided inside the opening / closing member, and the transfer member is moved to the pressing position or the separation position with respect to the image carrier by opening / closing the guide. A configuration is disclosed. After the replacement operation of the image carrier unit is completed and the open / close member is closed, it is easily and reliably detected that the transfer member that has been moved to the separated position as described above is forgotten to be returned to the pressing position. Technology is disclosed.

  Further, in the image forming apparatus having the above configuration, when the openable / closable guide integrally includes the transfer member, the guide opening / closing is performed between the image carrier unit and the guide in order to position the transfer member with respect to the image carrier. It is desirable to provide a lock mechanism for restricting (see Patent Document 3).

JP-A-8-50438 (FIG. 14) JP 2006-308799 A (FIGS. 4 and 5) JP 2006-235655 A (FIG. 6)

  However, in the configuration of Patent Document 2, when the image carrier unit is attached to the image forming apparatus to which the image carrier unit is not attached, the opening and closing member is opened and closed in a state where the pressing of the transfer member is forgotten to be released. There is a risk of it. In this case, when closing the opening / closing member, the reaction force of the pressing force of the transfer member against the image carrier is applied to the user who operates the opening / closing member, making it difficult to close the opening / closing member.

  In the configuration in which the lock mechanism is provided, the opening / closing of the guide having the transfer member cannot be locked when the image carrier unit is not mounted inside the apparatus. For this reason, there is a risk that the guide and the transfer member that the guide integrally has are damaged by vibration or impact during transportation.

Accordingly , an object of the present invention is to lock the opening and closing of the opening and closing member with respect to the apparatus main body regardless of the presence or absence of the image carrier unit in the apparatus main body.

A typical configuration of the present invention for solving the above-described problems is an image carrier unit that is detachable from an image forming apparatus main body and has an image carrier, and a developer image formed on the image carrier. a transfer member onto a recording medium, to lock the closing member, a state where the closing member is closed with respect to the image forming apparatus main body for holding the transfer member provided to be opened and closed in the image forming apparatus main body an image forming apparatus for chromatic and locking mechanism, wherein the closing member, by the locking mechanism, if the image bearing member unit is attached to the image forming apparatus main body is locked to the image bearing member unit, the If the image bearing member unit is not mounted to the image forming apparatus main body is characterized by that will be locked to the image forming apparatus main body.

According to the present invention , the open / close member can be closed and locked regardless of the presence or absence of the image carrier unit in the apparatus main body. Therefore, even when there is vibration or impact during transportation when the image carrier unit is not mounted inside the apparatus, it is possible to prevent the opening / closing member and the transfer member integrated with the opening / closing member from being damaged.

Schematic cross-sectional view showing schematic configuration of image forming apparatus A perspective view of a pressure mechanism having a function of pressurizing the secondary transfer roller so that the pressure can be released and a function of locking the transfer guide so as to be unlocked. Sectional drawing which shows the pressurization state and pressurization release state of a secondary transfer roller Sectional drawing which shows the said pressurization mechanism in the state in which the intermediate transfer unit is mounted, the secondary transfer roller is pressed, and the transfer guide is locked Sectional drawing which shows the said pressurization mechanism in the state by which the intermediate transfer unit was mounted | worn, the pressure of the secondary transfer roller was cancelled | released, and the lock | rock of the transfer guide was cancelled | released Sectional drawing which shows the said pressurization mechanism in the state by which the transfer guide is locked to the apparatus main body without attaching an intermediate transfer unit

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the following embodiments should be appropriately changed according to the configuration of the apparatus to which the present invention is applied and various conditions. Therefore, unless specifically stated otherwise, the scope of the present invention is not intended to be limited thereto.

  First, a schematic configuration of the image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of the image forming apparatus.

  In FIG. 1, 21 is a feeding cassette, 22 is a pickup roller, 23 is a feed roller, 24 is a retard roller, 42 is a transport roller, and 25 is a pair of registration rollers, which are provided in the main body of the image forming apparatus.

  In FIG. 1, reference numerals 28, 29, 30, and 31 denote photosensitive drums, which are held by the apparatus main body so as to be detachable in the central axis direction of the photosensitive drum by opening an opening / closing member 41 that also serves as an exterior. This photosensitive drum constitutes a process cartridge that can be attached to and detached from the apparatus main body together with a developing device (not shown) described later. Reference numeral 32 denotes a laser scanner serving as an exposure unit, which exposes the photosensitive drum.

  In FIG. 1, 33 is a fixing device, 34 is a discharge roller pair, and 35 is a discharge tray, which are provided at the top of the image forming apparatus main body.

  In FIG. 1, reference numeral 27 denotes an intermediate transfer unit as an image carrier unit. The intermediate transfer unit 27 includes an intermediate transfer belt 27B as an image carrier, and is provided so as to be detachable from the image forming apparatus main body. The intermediate transfer belt 27B, which is an endless belt, is stretched by a driving roller 27D and a tension roller 27T. The secondary transfer roller 26 is in contact with the driving roller 27D via the intermediate transfer belt 27B. Reference numerals 39Y, 39M, 39C, and 39Bk denote primary transfer rollers that are pressed by springs toward the respective photosensitive drums via the intermediate transfer belt 27B. At each primary transfer portion where the photosensitive drum and the primary transfer roller face each other, the developer image on the photosensitive drum is sequentially transferred onto the intermediate transfer belt.

  The secondary transfer roller 26 is rotatably held by the transfer guide 50. The secondary transfer roller 26 is a transfer member that transfers the developer image formed on the intermediate transfer belt 27B to a recording medium. The transfer guide 50 that holds the secondary transfer roller 26 is a first opening / closing member that is provided in the image forming apparatus main body so as to be openable / closable. The transfer guide 50 is a guide for guiding the recording medium. On the outside of the transfer guide 50, an open / close door 41 as a second open / close member that forms the exterior of the image forming apparatus main body is provided so as to be openable and closable. Therefore, the intermediate transfer unit 27 can be attached to and detached from the apparatus main body by opening the transfer guide 50 and the opening / closing door 41 on the side surface of the main body.

  When forming an image on a recording medium with this image forming apparatus, first, several sheets as a recording medium are conveyed from the feeding cassette 21 by the pickup roller 22 and separated into only one sheet by the feed roller 23 and the retard roller 24. Is done. Thereafter, the sheet is conveyed to the registration roller pair 25 by the conveying roller 42, and temporarily stops here. On the other hand, the image exposed to the photosensitive drums 28 to 31 by the laser scanner 32 is developed by a developing device (not shown), and sequentially transferred to the intermediate transfer belt 27B. The image primarily transferred onto the intermediate transfer belt 27B proceeds to the secondary transfer roller 26, and the sheet stopped by the registration roller pair 25 starts to be conveyed again in accordance with the image. The image on the intermediate transfer belt 27B is collectively transferred to the sheet by the secondary transfer roller 26. The sheet on which the image has been transferred is fixed on the image by the fixing device 33 and is discharged onto the discharge tray 35 by the discharge roller pair 34.

  In the series of image forming processes described above, a nip pressure is necessary to transfer the image on the intermediate transfer belt 27B to the sheet at the secondary transfer portion, that is, the nip between the intermediate transfer belt 27B and the secondary transfer roller 26. It is. The configuration for generating the nip pressure of the secondary transfer portion will be described below.

  The pressure to the secondary transfer roller 26 is given using a pressurizing mechanism 60 as shown in FIG. 2 installed in a transfer guide 50 that opens and closes. The pressure mechanism 60 is provided in the transfer guide 50 and presses the secondary transfer roller 26 against the intermediate transfer belt 27B so that the pressure can be released. Specifically, in the pressure mechanism 60 of the secondary transfer roller 26 shown in FIG. 2, the transfer guide 50 holds both ends of the pressure shaft 62 rotatably, and the pressure blocks 54F and 54R are moved by the shaft of the transfer guide end. It is configured by holding it so that it can swing. The transfer guide 50 holds secondary transfer roller pressure springs 51F and 51R, respectively. The urging forces of the secondary transfer roller pressure springs 51F and 51R are applied to bearings 63F and 63R disposed at both ends of the secondary transfer roller 26 through pressure blocks 54F and 54R, respectively. As a result, a pressing force is applied to the secondary transfer roller 26 to generate a nip pressure at the secondary transfer portion.

  2 can pressurize and release the pressure on the bearings 63F and 63R at the end of the secondary transfer roller 26. When releasing the pressurization, the user operates the release handle 56 to rotate the release arms 57L and 57R connected to the rod 58, thereby rotating the pressure shaft 62. As a result, the pressure cams 59F and 59R provided at both ends of the pressure shaft 62 rotate to swing the pressure blocks 54F and 54R away from the bearings 63F and 63R. As a result, the pressure release state as shown in FIG. On the other hand, when changing from this state to the pressure state, the opening / closing door 41 provided on the side surface of the image forming apparatus main body is closed so that the pressure mechanism provided in the transfer guide 50 presses the secondary transfer roller 26. Operates as follows. That is, by closing the opening / closing door 41, a protrusion (not shown) provided on the opening / closing door 41 pushes the pressing arm 64 provided on the pressing shaft 62 to rotate the pressing shaft 62. As a result, the pressure cams 59F and 59R provided at both ends of the pressure shaft 62 rotate, and the pressure blocks 54F and 54R are swung in a direction in which they abut against the bearings 63F and 63R. As a result, a pressurized state as shown in FIG.

  Further, as shown in FIG. 2, hooks 52F and 52R are provided for locking the opening and closing of the transfer guide 50 when the transfer guide 50 is closed. The hooks 52F and 52R are locking mechanisms that are provided on the transfer guide 50 and lock the transfer guide 50 so as to be unlocked. That is, the hooks 52F and 52R are provided at both ends of the pressure shaft 62 so as to rotate in conjunction with the pressure shaft 62, and are connected to the pressure mechanism. As shown in FIG. 4, the hooks 52 </ b> F and 52 </ b> R are fixed to positioning pins 27 </ b> P provided at both ends of the intermediate transfer unit 27 in order to accurately position the transfer guide 50 and the secondary transfer nip portion. That is, the transfer guide 50 is locked to the intermediate transfer unit 27 by the hooks 52F and 52R when the intermediate transfer unit 27 is attached to the apparatus main body.

  Since the hooks 52F and 52R can rotate in conjunction with the pressure shaft 62, by operating the release handle 56, the engagement with the positioning pin 27P is released as shown in FIG. The lock can be released. When the release handle 56 is operated, first, the pressure applied to the bearings 63F and 63R is released as described above, and then the hooks 52F and 52R are released from the positioning pins 27P. Accordingly, the positional relationship of the respective components as shown in FIG. 5 is obtained, and the pressure of the secondary transfer roller 26 is released, and the lock of the transfer guide 50 having the secondary transfer roller 26 is released. That is, the pressure mechanism releases the pressure of the secondary transfer roller 26 in conjunction with the operation of releasing the lock of the transfer guide 50 by the hooks 52F and 52R. Here, the pressure mechanism is exemplified to operate so as to release the pressure of the secondary transfer roller 26 before the lock of the transfer guide 50 by the hooks 52F and 52R is released. Is not to be done. For example, the timing at which the hooks 52F, 52R are disengaged from the positioning pin 27P and the timing at which the bearing 63 is released from pressure may be the same. With this mechanism, the transfer guide 50 can be opened in a state in which the pressure applied to the bearings 63F and 63R (secondary transfer roller 26) is released.

  Next, a case where the intermediate transfer unit 27 is not mounted inside the apparatus main body will be described. FIG. 6 shows a state in which the transfer guide 50 is closed when the intermediate transfer unit 27 is not mounted inside the apparatus main body. When the intermediate transfer unit 27 is not attached to the apparatus main body, the transfer guide 50 is locked to the apparatus main body by hooks 52F and 52R. Specifically, as shown in FIG. 6, since the lock member 53F provided inside the apparatus main body restricts the movement of the restricting portion 65F (the shape represented by the hatched portion) of the hook 52F, the transfer guide 50 Can be controlled. The lock member 53R having the same shape also regulates the restricting member 65R of the hook 52R with respect to the hook 52R on the opposite side. Therefore, even when the intermediate transfer unit 27 is not mounted inside the apparatus main body, the transfer guide 50 can be closed and its opening / closing can be regulated. Further, by operating the release handle 56 to rotate the hooks 52F and 52R in the direction of the arrow in FIG. 5, the restriction of the hooks 52F and 52R by the lock members 53F and 53R is released. In this case, the restriction of the hooks 52F and 52R is released after the pressure of the bearing 63 is released. However, the timing at which the hooks 52F, 52R are detached from the lock members 53F, 53R and the timing at which the bearing 63 is released from pressure may be the same. Thereby, the transfer guide 50 can be opened in a state in which the pressure applied to the secondary transfer roller 26 is released.

  As described above, regardless of whether the intermediate transfer unit 27 is attached to the apparatus main body or not, the release handle 56 is operated to open the transfer guide 50 so that the secondary transfer roller 26 is pressurized. Is released. Therefore, when the transfer guide 50 is closed again, it can be closed with the same force each time without the user receiving the reaction force of the nip pressure of the secondary transfer portion. Even when the intermediate transfer unit 27 is not attached to the apparatus main body, the transfer guide 50 can be closed to restrict its opening and closing. Therefore, the transfer guide 50 and the secondary transfer roller 26 included in the transfer guide 50 are not damaged when the apparatus main body is transported when the intermediate transfer unit 27 is not attached to the apparatus main body.

  In the above-described embodiment, the intermediate transfer unit having the intermediate transfer belt as the image carrier is exemplified as the image carrier unit. However, the present invention is not limited to this. For example, the image carrier unit may be a cartridge integrally including a photosensitive drum as an image carrier. The same effect can be obtained even when the present invention is applied to an image forming apparatus in which a transfer member facing the photosensitive drum of the cartridge is held by an opening / closing member.

  In the above-described embodiment, the image forming apparatus using four process cartridges each including the photosensitive drum is illustrated. However, the number of use is not limited, and may be set as needed.

  In addition, the process cartridge that is detachable from the main body of the image forming apparatus exemplified in the above-described embodiment is a process that integrally includes any one of a charging unit, a developing unit, and a cleaning unit in addition to the photosensitive drum. Any cartridge may be used.

  In the above-described embodiment, the printer is exemplified as the image forming apparatus, but the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a copying machine or a facsimile machine, or another image forming apparatus such as a multi-function machine combining these functions. The same effect can be obtained by applying the present invention to these image forming apparatuses.

26 ... Secondary transfer roller 27 ... Intermediate transfer unit 27B ... Intermediate transfer belt 27D ... Drive roller 27P ... Positioning pin 27T ... Tension rollers 28, 29, 30, 31 ... Photosensitive drum 41 ... Opening / closing door 50 ... Transfer guides 51F, 51R ... secondary transfer roller pressure springs 52F and 52R ... hooks 53F and 53R ... lock members 54F and 54R ... pressure blocks 56 ... release handles 57L and 57R ... release arms 58 ... rods 59F and 59R ... pressure cams 60 ... pressure Mechanism 62 ... Pressure shaft 63F, 63R ... Bearing 64 ... Pressure arm 65F, 65R ... Regulator

Claims (7)

It is detachable from the image forming apparatus main body, and the image carrier unit having an image bearing member, the developer image formed on the image bearing member and the transfer member onto a recording medium, the image forming apparatus main body a closing member which openably provided for holding the transfer member, in an image forming apparatus which have a, and a lock mechanism for locking the state where the closing member is closed with respect to the image forming apparatus main body,
The opening and closing member, by the locking mechanism, if the image bearing member unit is attached to the image forming apparatus main body is locked to the image bearing member unit, mounted the image bearing member unit is in the image forming apparatus main body the image forming apparatus if not, characterized in that that will be locked to the image forming apparatus main body. The lock mechanism includes a hook provided on the opening / closing member, the image carrier unit includes an engaging portion that engages with the hook, and the image carrier body includes the image carrier unit and the image formation device. The image forming apparatus according to claim 1, further comprising a regulating member that regulates movement of the hook that is not attached to the main body and cannot be engaged with the engaging portion. The image forming apparatus according to claim 2, wherein the restricting member is provided at a position that does not contact the hook when the opening / closing member is closed with respect to the image forming apparatus main body. The image forming apparatus according to claim 1, wherein the engaging portion is a positioning portion of the image carrier unit with respect to the main body of the image forming apparatus. 5. The image formation according to claim 1, wherein the opening / closing member includes a pressurizing mechanism that pressurizes the transfer member against the image carrier so that the pressurization can be released. apparatus.   6. The image forming apparatus according to claim 1, wherein the image carrier unit is an intermediate transfer unit having an intermediate transfer belt as the image carrier.   The image forming apparatus according to claim 5, wherein the pressurizing mechanism operates to release the pressurization of the transfer member before the lock of the opening / closing member by the lock mechanism is released.

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