JP2002311663A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the occurrences of jamming, a defective image and the damage of members by improving the feeding property of a recording medium without disturbing the miniaturization of an image forming device, the improvement of printing efficiency and a maintainability. SOLUTION: When a lever member 50 is moved from a first position which is a pressing position during the moving operation of a feeding member 41 from a second position to the first position, the moving operation of the feeding member is stopped by making a lever regulating protrusion part 50c and a main body regulating protrusion part 52b abut by providing the lever regulating protrusion part 50c to the lever member 50 and the main body regulating protrusion part 52b to the inside of an image forming device main body 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic image forming apparatus or an image forming apparatus having a protective shutter for an image carrier.

[0002]

2. Description of the Related Art An image forming apparatus for forming an image on a recording medium using an electrophotographic image forming process includes, for example, an electrophotographic copying machine, an electrophotographic printer (for example, an LED printer, a laser beam printer, etc.), an electrophotographic facsimile. Device and an electrophotographic word processor.

In conventional copiers and printers, when the distance between an image carrier (hereinafter, referred to as "photosensitive member") and a fixing means (hereinafter, referred to as "fixing device") is short, the distance between the photosensitive member and the fixing device is reduced. A rotation fulcrum at the time of releasing from a fixed position at the time of image formation of a transporting means for carrying and transporting a recording medium, which is located between the transfer section and the fixing section to secure a jam clearance space therebetween. Is provided on the downstream side in the recording medium transport direction, and the transport means is rotated by turning a handle or the like.

In some cases, a rotation fulcrum at the time of release of the conveying means for conveying the recording medium to the fixing device is provided on the upstream side in the recording medium conveying direction. Similarly, by turning a handle or the like, the conveying means is rotated. It is known to move the photosensitive member and a fixing device to secure a jam clearance space between the photosensitive member and the fixing device.

[0005]

However, as shown in FIG. 11, in an image forming apparatus for transferring a toner image formed on the surface of a photoreceptor 1 to a recording medium by a transfer roller 6 as a transfer means, a transfer section is provided. The conveying unit 71, which is located between the fixing unit and the fixing unit, carries the recording medium onto which the unfixed toner image has been transferred, and conveys the recording medium to the fixing unit from the fixed position A during image formation to the position B. In the case where the rotation fulcrum 71a for releasing is provided on the downstream side in the recording medium transport direction, the gap between the fixing entrance lower guide 46 and the fixing entrance lower guide 46 is largely opened in the lateral direction L and the height direction H. This is because the gaps L and H must be ensured so as not to interfere with the fixing entrance lower guide 46 when the conveying means 71 rotates.

However, when the gap is large in the lateral direction L, when a recording medium having a downward curl is conveyed, the recording medium cannot be transferred to the fixing entrance lower guide 46 properly, so that the recording medium may be jammed below. There is a danger that the leading edge of the sheet may catch the fixing entrance lower guide 46 and cause skew, or the impact of the catch may transmit the recording medium and affect the transfer section, resulting in image defects such as transfer misregistration. .

On the other hand, in a device in which the height direction H is increased,
When a recording medium having a downward curl is conveyed, the leading end of the recording medium collides with the fixing entrance lower guide 46, and there is a danger that the recording medium may be skewed, jammed, or an image defect may occur.

As described above, when the rotation fulcrum 71a for releasing the conveying means 71 is provided on the downstream side in the recording medium conveying direction, a gap of the transfer portion must be secured to some extent. Problems easily occur.

Further, there is a transport means for transporting the recording medium to the fixing device as shown in FIG. 12, in which a rotation fulcrum for release is provided on the upstream side in the recording medium transport direction. In general, a conveying means is rotated to secure a jam clearance space between the photoconductor and the fixing device. Here, a state in which each member or unit inside the image forming apparatus is installed at a predetermined position during image formation is referred to as a first position, and each member or unit is placed in the first position for maintenance such as a jam.
The position moved from the position is referred to as a second position. Also, here, the rotation direction of the member is shown as a rotation direction when the traveling direction of the recording medium in the image forming apparatus is set from right to left according to the front view of the image forming apparatus, and "clockwise", or Described as "counterclockwise."

[0012] In the image forming apparatus shown in FIG. 12, a transport member is present on a transport path from the time when the recording medium is carried into the image forming apparatus to the time when the recording medium is unloaded, and supports several members for transporting the recording medium. A rotation fulcrum 41a for releasing the transport frame 41 from the first position at the time of image formation at the first position is on the upstream side in the recording medium transport direction, and the rotation fulcrum 19a of the transport means 19 provided on the transport frame 41. Is located on the upstream side in the recording medium transport direction, the transport unit 19 and the fixing entrance lower guide 4
6 (the height direction H) can be reduced, and the lateral direction L
Are overlapped with each other, so that the recording medium can be smoothly delivered.

In such an image forming apparatus, the transport ribs 19, which are transport means, are rotatably supported by the transport frame 41 at a position close to the transfer position. As shown in FIG.
When the handle 51 is turned in the release direction (counterclockwise in FIG. 13) at the time of the jam clearance or the like, the transport frame 41 is rotated in the release direction (counterclockwise in FIG. 13) around the fulcrum 41a. At the same time, the protrusion 19c of the transport rib 19 moves away from the fixing stay 45 supporting the fixing device 7. At the same time, the transport rib 19 is rotated by a resilient member 44 that is installed at the rotation fulcrum 19a of the transport rib 19 provided on the transport frame 41 and urges in a direction away from the transport frame 41 (clockwise in FIG. 13). In conjunction with the direction (clockwise in FIG. 13) vertically rising from the fulcrum 19a, the downstream end 19b in the transport rib transport direction is fixed to the fixing stay 45.
Since the various transporting means (the transporting roller 10, the registration roller 11, the transfer roller 6, the transporting rib 19, etc.) move downward in conjunction with the transporting frame 41 without interfering with other parts, the jam clearance space is reduced. This ensures that the recording medium is not skewed, jammed, or has an image defect as described above.

However, since the photoconductor 1 and the fixing device 7 are located close to each other, the photoconductor 1 exists in the center of the jam processing space. Therefore, when the jam processing is performed in this space, the photoconductor 1 is removed. It has a fatal problem of being easily damaged.

In addition, recently, due to the miniaturization of the image forming apparatus, the components inside the apparatus are close to each other, and a sufficient space cannot be secured, and the user operates the recording medium to immediately output the recording medium. Together with the situation that it is desired to improve the number of output sheets per unit time of
In order to shorten the length of the recording medium transport path as much as possible, the distance between the photoconductor and the fixing device is often arranged as short as possible, and it is necessary to overcome the above problems and other various problems. Is becoming less common.

For example, the photosensitive member and the fixing device are required to be close to each other. Even if the same amount of downward curl of the recording medium as in the related art occurs, the distance to the transfer unit is short. There is also a problem that the image is easily transmitted to an image defect. This also causes a situation in which problems such as the above-described jam and damage to the photoconductor are likely to occur.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce the size of an image forming apparatus, improve the printing efficiency, and improve the transportability of a recording medium without hindering the maintainability. It is to provide a device.

[0016]

The above object is achieved by an image forming apparatus according to the present invention. In summary, the present invention provides:
An image carrier, a transfer unit that transfers a toner image on the image carrier to a recording medium at a transfer unit, and a fixing unit that fixes the toner image transferred to the recording medium surface at a fixing unit.
A shutter for protecting the image carrier, and a first position at the time of image formation in which the shutter is retracted from the image carrier,
An image forming apparatus comprising: a shutter rotating unit that rotates to a second position that protects the image carrier; and a shutter urging unit that urges the shutter to rotate to the second position. The first position at the time of the image formation in which the recording medium is conveyed to the fixing unit by passing through the transfer unit, the transfer unit is integrated, and the transfer unit is transferred to the recording medium; and A conveying member that is rotatably disposed at the second position to be separated from the image forming apparatus main body with respect to the image forming apparatus main body, with the upstream side in the recording medium conveying direction as a conveying member turning fulcrum; Is in contact with the shutter rotating means, and the transport member is
A lever member for rotating the shutter from the first position to the second position at the same time as rotating from the first position to the second position, wherein the lever member is provided with the shutter for the first position; A lever urging means for urging in a direction to rotate to a position, a lever restricting protrusion provided by projecting a part of the lever member, and a main body restricting protrusion provided inside the image forming apparatus main body. By abutting the lever regulating protrusion and the main body regulating protrusion,
During the movement operation of the conveyance member from the second position to the first position, when the lever member moves from the biased position of the first position, the movement operation of the conveyance member may be stopped. An image forming apparatus is provided.

According to one embodiment of the present invention, the lever member has a release projection projecting below a lever rotation fulcrum provided on the transport member, and the transport member has moved to the second position. At this time, an abutting portion provided at a position lower than the lever member inside the image forming apparatus main body pushes up the lever release projection and regulates a rotation angle of the lever member.

According to another embodiment of the present invention, the image carrier, cleaning means for scraping residual toner on the image carrier, the shutter, the shutter urging means, and the shutter rotating means. And are integrated and installed as a process cartridge.

According to another embodiment of the present invention, the transporting member is provided with a rotatable transporting means for supporting the recording medium from the transfer section to the fixing section. A moving support point includes a transfer unit biasing unit that biases the transfer unit in a direction away from the transfer member, and the transfer unit rotation fulcrum is provided on the transfer unit side of the transfer member.

According to another embodiment of the present invention, a distance between the fixing unit and the transfer unit is shorter than a minimum size of the recording medium.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an image forming apparatus according to the present invention will be described in more detail with reference to the drawings. However, the dimensions, material, shape,
The relative position and the like are not intended to limit the scope of the present invention to them unless otherwise specified.

Here, the rotation direction of the member is shown as a rotation direction when the traveling direction of the recording medium in the image forming apparatus is from right to left according to a front view of the image forming apparatus.
Described as “clockwise” or “counterclockwise”.

Embodiment 1 First, the overall configuration of the image forming apparatus main body will be described. FIG.
, The image forming apparatus main body 100 has a scanner unit 101 as an image reading unit for reading image information of an image surface of a book document at an upper part thereof, and an image forming unit 102 as an image forming unit at a lower part thereof. Further, a recording medium deck 103 is attached to a lower portion thereof.

The scanner unit 101 includes a scanning system light source 61, a platen glass 62, a document pressure plate 63 that can be opened and closed with respect to the apparatus main body 100, a first mirror 64, a second mirror 65, and a third mirror.
It has a mirror 66, a lens 67, a light receiving element (photoelectric conversion element) 68, an image processing unit, and the like.

The scanning system light source 61 and the first mirror 64 constitute a first mirror base, and the second mirror 65 and the third mirror 6
6, a second mirror base is formed, and scanning is performed in the scanning direction a. The moving state of the first and second mirror bases is indicated by a dashed line.

Then, a book original such as a book, thick paper, curled paper, or the like is placed on the platen glass 62 with the original surface of the original or sheet-like original facing down (to the platen glass 62 side). When the scanner is set in the stationary state and the reading start key of the operation unit (not shown) is pressed, the scanning system light source 61 scans the lower part of the platen glass 62 in the direction of arrow a to illuminate the image surface of the original, and the reflected light (image information) ) To the first mirror 64.

The image information of the document guided to the first mirror 64 passes through a second mirror 65 and a third mirror 66 to a lens 67.
The image data is projected on the light receiving element 68, the image information is read by the light receiving element 68, processed by an image processing unit (not shown), converted into an electric signal, and transmitted to the laser scanner 69 of the image forming unit 102.

Here, the image forming apparatus main body 100 functions as a copying machine when the processing signal of the image processing section is input to the laser scanner 69, and functions as a printer when the output signal of the personal computer is input. If a transmission signal from a facsimile device of another device is input or a processing signal of the image processing unit 101 is transmitted to a facsimile device of another device, the device functions as a facsimile device.

On the other hand, the recording medium deck 103 below the image forming unit 101 has a recording medium storage section and a sheet cassette 2.
1, the sheet cassette 21 is composed of a lower cassette 21a and an upper cassette 21b as one feeding unit.

The lower and upper cassettes 21a, 21b
The recording medium as a sheet accommodated therein is fed out by a pickup roller 22 serving as a feed rotating body, and is separated and fed one by one by the cooperation of a feed roller 23 and a retard roller 24. Transport roller pair 25,
It is conveyed by 26 or 27.

Then, the conveyed recording medium is stopped for a predetermined time so as to absorb the variation between the recording media by the pre-registration roller pair 28, and then rotated and conveyed. Then, the sheet is fed to the image forming unit 102 by the registration roller pair 11 in synchronization with the image forming operation.

The image forming section 102 includes a photosensitive member 1 as an image carrier, an image writing optical system 2, a developing device 3, a transfer roller 6, and the like. And the primary charger 5
The laser beam corresponding to the image information emitted from the laser scanner 69 is scanned by the image writing optical system 2 on the surface of the photoreceptor 1 uniformly charged by the laser scanner 69 to form a latent image. 3 forms a toner image, and the transfer roller 6 transfers the toner image to the first surface of the recording medium on the recording medium conveyed in synchronization with the rotation of the photoconductor 1 by the registration roller pair 11.

On the downstream side of the image forming unit 102 in the transport direction,
The apparatus includes a transport rib 19 as a guide unit, a fixing device 7 as a fixing unit, and a discharge roller pair 12. The recording medium on which the toner image has been formed is guided by a transfer rib 19 from a transfer section formed by the photoreceptor 1 and the transfer roller 6, and is conveyed to the fixing device 7, where the toner image is heated and pressed, and the toner image is formed. Settled on the surface.

The recording medium having been fixed is guided in the discharge direction, and is stacked by a discharge roller pair 12 on a discharge tray (upper part of the image forming unit 102) 13 having a function as a top cover. The recording medium is discharged face-down on the discharge tray 13 with the image forming surface facing down.

When images are recorded on both sides of the recording medium, the recording medium is passed through the fixing device 7 and then moved to the discharge roller pair 1.
2. The flapper 1 which is conveyed by a carry-out roller 14 connected thereto and whose rear end of the recording medium is a recording medium passage
Immediately after passing through the recording medium 5, while holding the recording medium, the discharge roller pair 14 is rotated in the reverse direction to invert the recording medium and once placed on the recording medium double-sided tray 16, and then the respective roller pairs 28, 10
The recording medium which has been conveyed to reach the registration roller pair 11 and is turned upside down is formed with an image on the second surface in the same manner as described above, and then discharged and stacked on the paper discharge tray 13. I have.

A pre-registration sensor lever 17 for detecting a recording medium is provided upstream of the registration roller pair 11 in the transport direction. When the recording medium is transported, the sensor lever 17 rotates. The detection of the recording medium by the sensor 18 is transmitted to the CPU of the image forming apparatus main body.

Next, an image forming unit 10 embodying the present invention will be described.
The second embodiment will be described below.

The image forming apparatus of this embodiment, like the conventional image forming apparatus described with reference to FIG. 12, rotates the transport frame, which is a transport member, at the time of maintenance such as a jam, and interlocks with the fixing frame. For releasing the transfer rib of the transfer means for supporting the recording material between the fixing device as the image bearing member and the photosensitive member as the image bearing member from the fixed position at the time of image formation as the first position and moving it to the second position. This is an image forming apparatus in which a transport member rotation fulcrum of the transport frame and a transport means rotation fulcrum of the transport rib are both located on the upstream side of the transport.

Here, a state in which each member and means inside the image forming apparatus are installed at a predetermined position during image formation is referred to as a first position, and each member and means are used for maintenance such as a jam. The position where the means is released from the first position is referred to as a second position.

The transport rib 1 has a schematic cross section as shown in FIG.
9 shows a state where both the transport frames 41 are set at the first position. The image forming apparatus includes a photoconductor 1 and a cleaner unit 32 for scraping residual toner on the photoconductor 1, a screw 33 serving as a cleaning unit for feeding the scraped residual toner, and a charging roller 34 for charging the photoconductor 1.
And a developing unit 3 for developing the latent image of the photoconductor 1 with toner is provided adjacent to the process cartridge 31.

The process cartridge 31 receives the photosensitive member 1 from below the photosensitive member 1 to protect the photosensitive member 1 at the second position where the photosensitive member 1 is separated from the transfer roller 6 of the transfer means for maintenance or the like. And a shutter 38 for protecting the surface. The shutter 38 is linked to the operation of a shutter arm 36 which is a shutter rotating means provided on the front surface of the process cartridge 31.

The state of the front surface of the process cartridge 31 will be described with reference to FIG. A shutter arm 36 rotatably held by a cylindrical boss 35a is provided as a shutter fulcrum rotation fulcrum provided on the frame 35 of the process cartridge 31, and an elastic member (spring) 37 as a shutter urging means. 4, the shutter 38 is constantly urged in the direction toward the second position for protecting the photoconductor 1, that is, counterclockwise in FIG. The two-dot chain line in FIG.
The shutter 38 and the shutter arm 36 at the position A and at the second position B for protecting the photoreceptor 1 are shown.
Arrangement.

The shutter arm 36 has an arm portion 36a for rotatably holding a shutter 38 for protecting the photoreceptor 1, and a cam surface 36b. Shutter 38
Is provided with a holding portion 38a of the arm portion 36a and a shutter shaft holding portion 38b for rotatably holding the shutter shaft 39. The shutter shaft 39 is a front hole 35b which is a shutter rotation fulcrum of the process cartridge frame 35.
, Are rotatably held in opposing holes (not shown) on the back side. As a result, the rotation of the shutter arm 36 causes the shutter 38 to rotate to a second position B for protecting the photoconductor 1 during maintenance or the like, and to a position A where the shutter 38 is retracted from the photoconductor 1 at the first position during image formation or the like. Can move.

The transport rib 19 is released from the first position and the second
In order to protect the photoreceptor 1 when moving to the position, the shutter 38 is positioned to receive the photoreceptor 1 immediately below the photoreceptor 1, and in order to contact the transfer roller 6 with the photoreceptor 1 during image formation, The shutter 38 is separated from the photosensitive member 1 and rotates clockwise around the cartridge 31 to return to the first position of the cartridge 31 on the fixing device side. As shown in FIG. 5, the process cartridge 31 is provided with a cover 40 on the front side for covering these moving parts.

In FIG. 3, a transfer roller 6 is supported by a transfer arm 42 at a portion facing the photosensitive member 1 through which a recording medium passes, and the transfer roller 6 is attached to the photosensitive member 1 by a spring 43 at a predetermined pressure. It is being rushed. As described above, the transfer roller 6 is urged against the photoreceptor 1, and a transfer portion is formed at the nip portion, and the toner image is transferred to the recording medium at the transfer portion.

The transfer arm 42 supported by the transfer roller 6 is provided on the transfer frame 41. When the transfer frame 41 rotates, the transfer means 4 including the transfer roller 6 moves integrally. I do.

A transport rib 19 serving as transport means for transporting the recording medium transferred by the transfer unit and transporting it to the fixing device 7 is attached to the transport frame 41 so as to be rotatable about a fulcrum 19a. A spring 44 is attached to the fulcrum 19a and urges the transport rib 19 clockwise. When the transport rib end 19c contacts the bottom surface of the fixing stay 45 supporting the fixing device 7, the position is adjusted. Is determined.

The fixing entrance lower guide 46 for guiding the recording medium conveyed from the conveying ribs 19 to the fixing device 7 has ribs disposed in the longitudinal direction (axial direction of the photoreceptor). And overlap. This overlap allows the recording medium to be smoothly fixed to the lower entrance guide 4.
6

The transport frame 41 is rotatable about a transport member rotation fulcrum 41a near the recording medium carry-in position, and abuts a positioning portion (not shown) of the process cartridge 31 by a pressing plate 48 lifted by a cam 47. The transfer unit and the transfer guide unit are
At a predetermined position.

Further, as shown in FIG.
A shutter lever 50, which is a lever member that is urged by an elastic member 49 that urges clockwise in FIG.

The shutter lever 50 is connected to the transport frame 4
1 is a plate-like member installed on the front of the apparatus. The shape of the shutter lever 50 is such that, at the first position in the image forming state, one side overlaps with the transport frame 41, and the upstream side in the recording medium transport direction is a right angle among the corners sandwiching the one side. The projecting right triangle is the basic shape. One corner of the right triangle that is not a right angle is defined as a lever rotation fulcrum 50d, and has a lever projection 50a projecting upward and a release projection 50b projecting downward from the basic right triangle.

The shutter lever 50 is urged by the elastic member 49 in a direction (clockwise in FIG. 6) in which the right triangle falls on the transport frame 41.
In the first position, the transfer frame 41 is fixed at a fixed position by a front protrusion 41c protruding forward.

When the upper end 50a of the shutter lever 50 is
The shutter arm 36 comes to a position where the shutter arm 36 is caught by a concave portion provided in the vicinity of the rotation fulcrum 35a.
The shutter 38 comes to the first position A (FIG. 6, solid line) where the shutter 38 is retracted from the photoconductor 1 by a predetermined rotation amount of the shutter arm 36 pushed up at 0 a.

FIG. 7 shows the operation at the time of jam clearance.

When a jam occurs, the handle 51 is first turned counterclockwise as shown in FIG.
The cam 47 also rotates counterclockwise in FIG. 7, and the pressing plate 48 falls accordingly, and the transport frame 41 starts rotating counterclockwise about the fulcrum 41 a, and the transport frame 41 falls downward. become.

When the transfer frame 41 starts to fall, the transfer rib 19 is turned by the biasing force of the spring 44.
In FIG. 7, the fulcrum 19a is dropped while the transport rib projection 19c is in contact with the fixing stay 45 in such a direction that the portion close to the fixing device 7 floats around the axis. Therefore, the transport rib end 19b can rotate without interfering with the fixing entrance lower guide 46 and the like.

Further, the shutter lever 50 starts to rotate simultaneously with the transfer frame 41. The cam surface 36b of the shutter arm 36 of the process cartridge 31 rotates counterclockwise in FIG. 7 while contacting the upper end portion 50a of the shutter lever 50 by the urging force of the elastic member 37. Approaching the second position to protect.

Next, FIG. 2 shows a state of the second position where the exterior (not shown) of the image forming apparatus is opened, the transport frame 50 is completely released, and the jam processing can be performed. In this state, the transport rib 19 is rotated clockwise by the spring 44 and comes into contact with the projection 41b on the transport frame, so that the transport rib 19 stops at a fixed angle.

At this time, the inner cover 5 on the image forming apparatus main body side is used.
2, the striking portion 52a is provided, but the striking projection 50b provided on the shutter lever 50 is struck from below, whereby the shutter lever 50 is rotated counterclockwise to maintain a jam clearance space. Have been.

As described above, since the shutter lever 50 has a right-angled triangular shape with the base overlapped on the front of the transport frame 41, the release projection 50b projecting below the shutter lever 50 also projects below the transport frame 41. (FIG. 6).

The shutter lever 50 is connected to the transport frame 4
Since the first fixing device 7 side tip is set as a rotation fulcrum 50d and urged in the direction of falling toward the transport frame 41, that is, clockwise, if the release projection 50b is not pushed up by the abutting portion 52a, the transport frame 41 On the other hand, it falls together with the transport frame 41 in the same state with one side of the right triangle being overlapped.

The release projection 50b or the abutting portion 5
FIG. 8 shows the state of the jam processing space when there is no 2a. Since the non-right angle of the right triangle of the shutter lever 50 is set as the rotation fulcrum 50d, the transport frame 41
Is rotated counterclockwise with the end on the upstream side of the recording medium conveyance as a rotation fulcrum 41a.
8a protrudes upward from the transport rib 19 fixed by the frame protrusion 41b, and does not appear to protrude so much in FIG.
It turned out that it was very difficult to work if there was a tall object in front of the jam clearance space.

With the release projection 50b, the shutter lever 50 is pushed up from below the transport frame 41 by the abutting portion 52b provided below, and the end of the transport frame 41 near the fixing unit 7 is used as a fulcrum. It is possible to rotate counterclockwise, so that the upper end portion 50a that becomes an obstacle during jam processing can be pushed counterclockwise, and can be avoided outside the area from the transfer unit 6 to the fixing unit 7. At the second position, it can be seen that a large space is provided above the transport frame 41, that is, above the transfer roller 6 to the position of the photoconductor 1.

Referring to FIG. 2 again, even if the operator touches and pushes the transport rib 19 or the shutter lever 50 during the jam clearance, the operator can turn to the two-dot chain line position counterclockwise. Since the configuration and the space are ensured, the jam clearance space is further secured.

After the jam has been cleared, the handle 51 is turned clockwise to rotate the transport frame 41. At this time, the frictional force between the cam surface 36b of the shutter arm 36 and the distal end portion 50a of the shutter lever 50 urges the shutter lever 50 clockwise due to, for example, inaccuracies or unexpected defects due to the accumulation of many component tolerances. Assuming that the elastic force is greater than the elastic force of the elastic member 49, the upper end projection 50a of the shutter lever 50 may come off the cam surface 36b of the shutter arm 36.

Then, since the shutter arm 36 is urged counterclockwise in FIG. 1 in a direction in which the shutter 38 covers the photosensitive member 1, unless the shutter lever 50 pushes the shutter arm 36 clockwise, In the operation, the operation of returning to the second position is performed during the operation of rotating toward the fixed position of the first position. That is, the shutter 38 rotates in a direction to protect the photoconductor 1 from below.

On the other hand, the transport frame 41 continues to return to the first position irrespective of the operation of the shutter 38 and rises so as to come into contact with the photoreceptor 1, so as shown in FIG. The transfer roller 6 collides with the shutter 38 that is approaching the position for protecting the transfer roller 1, which may damage the transfer roller 6 and cause an image defect.

Therefore, as shown in FIG. 1, on the shutter lever 50 side, the side on the side that does not oppose the right-angled triangular shutter arm 36 of the shutter lever 50 and does not contact the transport frame 41, that is, the fixing device 7 A lever restricting protrusion 50c is provided on the oblique side of the side, and the inner cover 52 of the image forming apparatus main body adjacent to the fixing device 7 side of the cartridge 31 is provided on the image forming apparatus main body side so as to abut the protrusion 50c. A regulating projection 52b is provided.

When the lever regulating protrusion 50c provided on the slope of the shutter lever 50 and the main body regulating protrusion 52b provided on the image forming apparatus abut against each other, the transport frame 41 can be lifted above the cover regulating protrusion 52b. Therefore, even if the distal end portion 50a of the shutter lever 50 is disengaged from the shutter arm cam surface 36b, the rotation by the handle 51 can be stopped so that the transfer roller 6 does not hit the shutter 38.
The transfer roller 6 can be protected.

As described above, the tip end 50a of the shutter lever 50 should be connected to the cam surface 36 of the shutter arm.
b, the protrusion 50c on the shutter lever side and the regulating protrusion 52b of the inner cover 52 on the image forming apparatus main body side are brought into contact with each other.
1 can be stopped, a collision between the transfer roller and the shutter 38 can be prevented, and the transfer roller can be protected.

On the other hand, as described with reference to FIG. 2, by providing the release projection 50b on the shutter lever 50 and the abutting portion 52a that abuts on the release projection 50b on the inner cover 52 of the image forming apparatus main body side, the jam clearance is improved. Sometimes the shutter lever 50 is turned counterclockwise,
There is an effect that a jam processing space can be maintained.

In this embodiment, the rotation fulcrum of the transport means is provided on the upstream side in the transport direction of the recording medium.
It is not a limitation.

Normally, an image forming apparatus having this configuration is
As in this embodiment, the photosensitive member, the cleaning means for removing residual toner on the photosensitive member, and the shutter are integrated as a process cartridge. However, these members may be made into a cartridge by another combination. Alternatively, each of them may be separately installed in the image forming apparatus.

Further, in the embodiment of the present invention, the size of the image forming apparatus is reduced, the components in the apparatus are made closer to each other, the output of the recording medium is shortened by a user operation, and the recording medium is conveyed for improving the productivity of the recording medium. By shortening the path, the distance between the photoconductor and the fixing unit is shortened, and the length of the line connecting the photoconductor and the fixing unit of the fixing unit is only about 95 mm. The distance is shorter than 139.7 mm of the statement of the paper.

[0075]

As described above, according to the image forming apparatus of the present invention, the transfer member abuts the transfer means on the image carrier at the first position during image formation, and the transfer member at the second position during image formation. The shutter that can be separated from the image carrier, and protects the image carrier, is moved from the first position at the time of image formation retracted from the image carrier by shutter rotating means.
It has a shutter urging means which is rotatable to a second position for protecting the image carrier and urges the shutter to rotate to the second position, and the conveying member is in contact with the shutter rotating means. A lever member for rotating the shutter from the first position to the second position at the same time as the transport member rotates from the first position to the second position, wherein the lever member moves the shutter to the first position. (A) the lever member is moved from the first position of the urging position during the operation of moving the transport member from the second position to the first position. When moving the transport member,
The lever is stopped when the lever regulating protrusion provided on the lever member and the main body regulating protrusion provided inside the image forming apparatus main body come into contact with each other. Further, (B) the lever member rotates the lever provided on the transport member. The transport member has a lever restricting portion protruding below the fulcrum, and when the transport member moves to the second position, the transport member moves to a position below the lever member inside the image forming apparatus main body,
An abutment portion is provided, and the abutment portion pushes up the lever regulating portion to adjust the rotation angle of the lever member. It is possible to avoid damage to the transfer means and the image carrier, to reduce the size of the image forming apparatus, to shorten the recording medium conveyance path, to shorten the distance between the photosensitive member and the fixing device, to shorten the output time, and to improve the recording medium productivity. There is an effect that it can sufficiently contribute to improvement.

[Brief description of the drawings]

FIG. 1 is a front view around a process cartridge provided in an image forming apparatus of the present invention.

FIG. 2 is a schematic configuration diagram of a second position of the image forming apparatus of the present invention.

FIG. 3 is a schematic configuration diagram of a first position of the image forming apparatus of the present invention.

FIG. 4 is a front view of a process cartridge provided in the image forming apparatus of the present invention.

FIG. 5 is a front view of a process cartridge provided in the image forming apparatus of the present invention, in which a cover is put on the process cartridge.

FIG. 6 is a front view of a first position around a process cartridge provided in the image forming apparatus of the present invention.

FIG. 7 is a schematic configuration diagram of the image forming apparatus of the present invention when an internal member is moved.

FIG. 8 is a schematic configuration diagram showing a comparative example of the image forming apparatus of the present invention.

FIG. 9 is a schematic configuration diagram illustrating a comparative example of the image forming apparatus of the present invention.

FIG. 10 is a front view of the image forming apparatus of the present invention.

FIG. 11 is a schematic configuration diagram of a conventional image forming apparatus.

FIG. 12 is a schematic configuration diagram illustrating a state of a first position of a conventional image forming apparatus.

FIG. 13 is a schematic configuration diagram illustrating a state of a second position of the conventional image forming apparatus.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 photoconductor (image carrier) 4 transfer means 6 transfer roller 7 fixing device 19 conveyance rib (conveyance means) 19a conveyance rib rotation means 31 process cartridge 33 cleaning means 35 process cartridge frame 35a shutter arm rotation fulcrum 35b shutter rotation Moving fulcrum 36 Shutter arm (shutter rotating means) 36a Shutter arm portion 36b Shutter cam surface 37 Spring (shutter biasing means) 38 Shutter 41 Transport frame (transport member) 41a Transport member pivot fulcrum 41b Frame protrusion 43 Spring (transfer) Means urging means) 44 spring (conveying means urging means) 45 fixing stay 46 fixing guide lower guide 47 handle cam 48 pressure plate 49 elastic member (lever urging means) 50 shutter lever (lever member) 50a lever projection 50 Lever release projection 50c lever restricting protrusion 50d lever rotation fulcrum 51 within the handle 52 cover 52a abutting portion 52b protruding portion (main regulating protrusions)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H071 BA03 BA15 BA19 BA22 BA23 BA27 BA29 BA32 CA05 DA09 DA15 DA23 DA26 2H072 BA03 BA12 CA01 CB03 CB08 EA16 EA18 FB01 JA02 JA04 2H200 FA09 FA12 GA23 GB25 HA03 HB12 HB22 JA02 LA08 LA28 LA38 3F101 FA01 FB05 FB07 FC05 FE02 FE06 FE08 LA02 LA05 LA07 LB03

Claims (5)

[Claims] An image carrier; a transfer unit configured to transfer a toner image on the image carrier to a recording medium at a transfer unit; and a fixing unit configured to fix the toner image transferred to the recording medium surface. Fixing means, a shutter for protecting the image carrier,
Shutter rotating means for rotating from a first position during image formation in which the shutter retracts from the image carrier to a second position for protecting the image carrier, and the shutter rotating to the second position And a shutter urging unit that urges the recording medium to pass through the transfer unit to the fixing unit, integrates the transfer unit, and sets the transfer unit to a recording medium. A transfer member rotation fulcrum is provided at the first position at the time of the image formation to be transferred to the image forming apparatus and at the second position at a distance from the image carrier, with respect to the image forming apparatus main body. A transport member rotatably disposed as a contact member with the shutter rotating means, and simultaneously when the transport member rotates from the first position to the second position, The shuffle A lever member for rotating the shutter from the first position to the second position, wherein the lever member biases the shutter in a direction for rotating the shutter to the first position. Means, a lever regulating protrusion is provided by projecting a part of the lever member, and a body regulating protrusion is provided inside the image forming apparatus body, and the lever regulating protrusion and the body regulating protrusion are provided. When the lever member moves from the biased position of the first position during the movement operation of the transfer member from the second position to the first position, the movement of the transfer member An image forming apparatus, the operation of which is stopped. 2. The image forming apparatus main body according to claim 2, wherein said lever member has a release projection projecting below a lever rotation fulcrum provided on said transport member, and said transport member moves to said second position when said transport member moves to said second position. 2. The image forming apparatus according to claim 1, wherein an abutting portion provided at a position below the internal lever member pushes up the lever release projection and regulates a rotation angle of the lever member. 3. . 3. The image carrier, a cleaning unit for scraping residual toner on the image carrier, the shutter, the shutter urging unit, and the shutter rotating unit are integrated as a process cartridge. The image forming apparatus according to claim 1, wherein the image forming apparatus is installed after being installed. 4. The transporting member, wherein a transporting means for supporting the recording medium from the transfer section to the fixing section is rotatably provided, and the transporting means is configured to move the transporting means to a transporting means rotation fulcrum. 4. A transport device biasing means for biasing the transport member in a direction away from the transport member, wherein the transport device rotation fulcrum is provided near the transfer portion of the transport member. An image forming apparatus according to any of the above items. 5. A distance between the fixing unit and the transfer unit,
The image forming apparatus according to claim 1, wherein the image forming apparatus is shorter than a minimum size of the recording medium.