JPH01142682A - Image forming device - Google Patents

Abstract

PURPOSE:To simplify and facilitate the locating operation of a developing device by making an upper supporting frame body which allows the movement between the developing position and the separating position of the developing device when it is in an opening position in a closing position. CONSTITUTION:Between a lower supporting frame body 6 and the upper supporting frame body 10, a unit frame 14 is turnably mounted and, moreover, a developing position locating means 118 is provided in relation to the developing device 28. When the upper supporting frame body 10 is in the opening position, the developing device 28 can freely move between the developing position and the separating position. And when the developing device 28 is in the separating position, the developing device 28 is located from the separating position to the developing position if the upper supporting frame body 10 is made in the closing position from the opening position. Thus the developing device 28 is surely located in the developing position, so that a fault, etc., in development is not caused.

Description

[Detailed description of the invention] Technical fields> The present invention relates to an image forming apparatus such as an electrostatic copying machine.

<Prior Art> An electrostatic copying machine as an example of an image forming apparatus includes a rotating drum having a photoreceptor disposed on its surface, an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the photoreceptor of the rotating drum, and an electrostatic copying machine as an example of an image forming apparatus. It is equipped with a developing device that develops the electrostatic latent image. In such an electrostatic copying machine, as disclosed in Japanese Patent Application Laid-Open No. 60-120378, for example, in order to facilitate mounting of the rotating drum and Ma, a developing device is located at a developing position close to the rotating drum, There is a developing device which is mounted so as to be movable between separate positions separated from the developing device, and movement of the developing device is accomplished by movement of an upper support frame body which is openably and closably mounted to a lower support frame body. That is, by moving the upper support frame to the open position, the developing device is positioned at the remote position, and by moving the upper support frame to the closed position, the developing device is positioned to the developing position.

However, such conventional electrostatic copying machines have the following problems to be solved. That is, when the upper support frame is placed in the open position, the developing device is always positioned at the remote position. It tends to act on the agent, and when it acts in this way, it causes toner scattering.

In addition, for maintenance of the transfer corona discharger located below the rotating drum, it is preferable that the circumferential surface of the rotating drum be covered by some means, and if it is placed in a separate position as in the past, the surface of the photoreceptor may be covered. There is a risk of damaging the

<Object of the Invention> The present invention has been made in view of the above facts, and its main purpose is to allow movement of the developing device between the developing position and the remote position when the upper support frame is in the open position. The above-mentioned problem is solved, and the developing device is positioned at the developing position by placing the upper support frame in the closed position, thereby making the positioning of the developing device easy and convenient. It is an object of the present invention to provide an image forming apparatus with improved characteristics.

<Summary of the Invention> According to the present invention, a support structure includes a lower support frame and an upper support frame attached to the lower support frame so as to be pivotable between an open position and a closed position; an image bearing means on which a body is disposed, an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the photoreceptor, and a developing device for developing the electrostatic latent image formed on the surface of the photoreceptor. In an image forming apparatus, the developing device is movable between a developing position for developing an electrostatic latent image in close proximity to the image bearing means and a remote position retreating from the developing position; selectively positioning the developing device in the developing position and the remote position; and means for moving the developing device in the remote position to the developing position by pivoting the upper support frame from the open position to the closed position. An image forming apparatus is provided, comprising means for positioning a developing position.

<Preferred Specific Example of the Invention> A specific example of the image forming apparatus according to the present invention will be described below with reference to the accompanying drawings. In a specific example, the present invention will be described with reference to an electrostatic copying machine as an example of an image forming apparatus, but the present invention can be similarly applied to other devices such as a laser beam printer.

Referring to FIGS. 1 and 2, the illustrated electrostatic copying machine includes a housing 2 having a substantially rectangular parallelepiped shape.

The housing 2 in the specific example includes a pair of support substrates 4 (see FIG. 1) spaced apart in the front-rear direction (direction perpendicular to the plane of paper in FIGS. 1 and 2).

A lower support frame 6 having a rear support substrate (only the rear support substrate is shown in FIGS. 2, 5, and 6) and a pair of support substrates 8 (FIGS. 1 and 6) spaced apart in the longitudinal direction Second
The support structure includes an upper support frame 10 (only the rear support substrate is shown in the figure). In FIGS. 1 and 2, the upper support frame 10 is rotatably attached to the lower support frame 6 via a shaft member 12 at its lower left end, and can be moved between the closed position shown in FIG. 1 and the open position shown in FIG. It is possible to freely rotate between.

A unit frame 14 is rotatably mounted between the lower support frame 6 and the upper support frame 1O. The illustrated unit frame 14 has a pair of end walls 16 and 18 (FIG. 3) arranged at intervals in the front-rear direction, and one end portion of the pair of end walls 16 and 18 (FIGS. 1 and 3). 2) is connected to the pair of support substrates 4 of the lower support frame 6 via the connection shaft 2o.
It is rotatably mounted in between. In addition, a pair of end walls 16
One end of a connecting member 22 (only one of which is shown in FIGS. 1 and 2) is rotatably attached to the other end of the connecting member 22 and 18, and the other end of the connecting member 22 is connected to the upper support frame 10. It is rotatably attached to a pair of support substrates 8. Since the unit frame 14 is mounted in this way, when the upper support frame 10 is in the closed position, the unit frame 14 is held in the operating position shown in FIG. 1, and when the upper support frame 10 is in the open position, The unit frame 14 is placed in the take-out position shown in FIG.

In a specific example, a rotating drum 24 (
A charging corona discharger 26, a developing device 28, and a cleaning device 30 are mounted on the unit frame 14. Further, an optical means (not shown) for projecting an original image onto the surface of the photoreceptor is attached to the upper support frame 10.

Furthermore, a copy paper supply means 32 , a conveyance mechanism 34 , a transfer corona discharger 36 , a peeling corona discharger 38 , and a tray 40 are attached to the lower support frame 6 .
has a cassette 42 that is detachably attached to a receiving portion defined in the lower support frame 6 and a feeding roller 44 that is disposed above the receiving portion, and the conveying machine fI34 has a guide plate 46 and a feeding roller 44 disposed above the receiving portion.
8. Fixing roller pair 50, guide plate 52, and discharge roller pair 5
Contains 4.

In the electrostatic copying machine as described above, when the upper support frame 10 is placed in the closed position, various components mounted on the lower support frame 6, various components mounted on the unit frame 14, and the upper support frame are removed. The various components attached to the body 10 are held in the positional relationships shown in FIG. 1 while the rotating drum 24 is driven to rotate in the direction indicated by the arrow 28, allowing the following copying process to be performed. , the charging corona discharger 26 charges the photoreceptor of the rotating drum 24 to a specific polarity, and then an optical means (not shown) projects an image of the document onto the surface of the charged photoreceptor, thus charging the photoreceptor 26. An electrostatic latent image is formed on the photoreceptor by the action of an electrostatic latent image forming means comprising an optical means and an electrostatic latent image forming means.

Thereafter, the electrostatic latent image on the photoreceptor is developed by the developing device 28. Next, the copy paper supplied from the copy paper supply means 32 is guided by the guide plate 46 and brought into close contact with the circumferential surface of the rotating drum 24, and the toner image on the photoreceptor is transferred to the copy paper by the action of the transfer corona discharger 36. transcribed. After that, the rotating drum 2 is removed by the action of the stripping corona discharger 38.
The copy paper is peeled off from 4. The peeled copy paper is guided
i4B, the copy paper is conveyed through a pair of fixing rollers 50, and during this conveyance, the toner image on the copy paper is fixed, and then discharged onto the tray 40. On the other hand, the rotating drum 24 continues to rotate, and the toner remaining on the window light body after the transfer is removed by the action of the cleaning device 30.

Next, the unit frame 14 and the developing device 2 attached thereto.
8th grade will be explained. With reference to FIGS. 3 to 6,
In a specific example, the developing device 28 is located between a developing position close to the rotating drum 24 (the position shown in FIGS. 1 and 5) and a position away from the developing position (the position shown in FIGS. 2 and 6). is attached so that it can be moved freely. To explain further, supporting means for supporting the developing device 28 is attached to the unit frame 14. The illustrated supporting means is the end wall 16 of the unit frame 14.
and 18 (FIGS. 5 and 6 show support members 60 and 62 attached to one end wall 16, and FIG. 3 shows support members 60 and 62 attached to the other end wall 16).
8), one of the support members 6o is brought into close proximity to the rotating drum 24 by attaching mounting screws 66 to the end wall 16 through a pair of elongated holes 64 formed therein. The other support member 62 is mounted so as to be movable in the direction of separation, and the other support member 62 is moved close to the rotating drum 24 by screwing a mounting screw 70 into the end wall 18 through a pair of elongated holes 68 formed therein. and is mounted so as to be movable in the direction of separation. Support members 60 and 62
As shown in FIGS. 3 and 5, a first receiving portion 72 is defined at one end close to the rotating drum 24, and a second receiving portion 74 is defined approximately at the center in the longitudinal direction. ing.

On the other hand, as shown in FIG. 4, the developing device 28 of the specific example includes a developing housing 76 that defines a developing chamber, and the developing housing 76 has a toner storage section 7 that defines a toner storage chamber.
8, and a toner cartridge 80 containing toner is removably attached to the toner storage portion 78. Further, a magnetic brush mechanism 82 is disposed in the -1 developing chamber for holding developer and applying toner to the electrostatic latent image.

A pair of end walls 84 and 86 of the developer housing 76 have a relatively large diameter first protrusion 88 corresponding to the first receiving portion 72 and a relatively large diameter first protrusion 88 corresponding to the second receiving portion 74. A second protrusion 9o with a small diameter is provided (only the one provided on the end wall 84 is shown in FIGS. 4 to 6). In the developing device 28 as described above, the first protrusion 8B and the second protrusion 90 provided on the end wall 84 are connected to the first receiving portion 72 and the second receiving portion 74 defined on the support member 60. By positioning the first protrusion 88 and the second protrusion 90 provided on the other end wall 86 in the first receiving part 72 and the second receiving part 74 defined in the support member 62. , support member 6
0 and 62 in a detachable manner. Furthermore, the developing device 28
In order to facilitate the above-described device, a guide member 94 defining a guide surface 92 extending diagonally downward is attached to the inner surface of the end walls 16 and 18 of the unit frame 14 (see FIG. 3). (Only those provided on the end wall 18 are shown)
.

The developing device 28 is selectively positioned at the developing position and the remote position by means of a means 96. The illustrated developing device positioning means 96 is the 31st:
! J and FIG. 5, the end wall 16 of the unit frame 14
and a rotary shaft 98 rotatably supported between the
Working pieces 100 and 102 are attached to both ends of this rotating shaft.

As shown in FIG.
The other working piece 102 is positioned between a pair of protruding pieces 10B and 110 provided on the other supporting member 62, as shown in FIG. Also,
The right end of the rotating shaft 98 in FIG.
An operating member 112 that rotates together with the controller 8 is provided.

With this configuration, the operating member 112 can be moved by the arrow 114.
When it is turned in the direction shown in FIG. 6 and positioned at the angular position shown in FIG. (approximately horizontally to the left in FIG. 5), thus supporting members 60 and 62
are positioned in the first position shown in FIG. (located at the right end in Figures and Figure 5)
. On the other hand, the operation member 112 is moved to the arrow 116 (contrary to the above).
When the actuating pieces 100 and 102 act on the protruding pieces 106 and 110 of the supporting members 6o and 62, when the actuating pieces 100 and 102 are rotated in the direction shown in FIG. (approximately horizontally to the right in FIG. 6), thus supporting members 6o and 62
are positioned in the second position shown in FIG. (located at the left end in Figures 3 and 5)
.

In connection with the developing device 28, a developing position positioning means 118 is further provided. As shown in FIGS. 5 and 6, the illustrated development position positioning means 118 is composed of a cam means 120 having an arcuate cam action portion 120a, and in a specific example, a lower portion corresponding to the operating member 112 is provided. A support plate piece 1 is attached to the inner surface of the support substrate 4 behind the support frame 6.
It is attached via 22. Such cam means 120
When the upper support frame 10 is moved from the open position to the closed position when the operating member 112 is in the angular position shown in FIG. Turn it in the direction shown and position it at the angular position shown in FIG.

In the specific example, in order to maintain the distance between the developing device 28, particularly the magnetic brush mechanism 82, and the circumferential surface of the rotating drum 24 at a predetermined value, the rollers are attached to the inner surfaces of the end walls 16 and 18 of the unit frame 14. The contact portion 126 is attached to the drum support member 124.
(FIG. 3 shows the contact portion provided on the rear drum support member, and FIGS. 5 and 6 show the contact portion provided on the front drum support member).

As described above, when the support members 60 and 62 are placed in the first position as described above, the first protrusion 88 in the developing device 2 comes into contact with the drum support member 124, respectively. The developing device 2
Movement beyond the development position No. 8 is reliably stopped, and the distance between the rotating drum 24 and the developing device 28 is maintained at a predetermined value set by the contact portion 126. In addition, the drum support member 1
A notch 127 is formed in the rotating drum 24.
4 is rotatably mounted between the drum support members 124 through the notch 127.

Further, the developing device 28 is provided with a toner concentration detecting means (not shown) for detecting the concentration of the developer, and is configured to apply a developing bias voltage to the magnetic brush mechanism 82. In this connection, the developer housing 7
One electrical connection terminal 128 (for example, a concave terminal) is provided at a predetermined portion of the unit frame 14, and the other electrical connection terminal 130 (for example, a convex terminal) is provided on the inner surface of the end wall 18 of the unit frame 14. It is being

In addition, in the specific example, the end walls 16 and 18 of the unit frame 14
In FIGS. 5 and 6, a bottle 132 is installed at the right end, and the pin 132 and the support members 60 and 6 are connected to each other.
A coil spring 134 is interposed between the protruding pieces 106 and 110 provided at 2 (only one is shown in FIGS. 5 and 6). The coil springs 134 resiliently bias the support members 60 and 62, respectively, toward the second position.

In such an electrostatic copying machine, when the upper support frame 10 is in the open position, the developing device 28 is movable between the developing position and the remote position.

That is, when the operating member 112 is rotated in the direction shown by the arrow 114 (FIG. 6) and positioned at the angular position shown in FIG. 5, the support members 60 and 62 are positioned at the first position shown in FIG. The developing device 28 supported by the supporting members 60 and 62 is held at the developing position shown in FIG. 5 (the position also shown in FIG. 1). The first protrusion 88 contacts the abutting portion 126 of the drum support member 124, thereby preventing the developing device 28 from moving beyond the developing position and moving the operating member 112 beyond the angular position shown in FIG. ), the distance between the developing device 28 and the rotating drum 24 is maintained at a predetermined value, and the magnetic brush mechanism 82 (FIG. 4)
The developer held in the drum acts on the surface of the photoreceptor of the rotating drum 24 as required. Furthermore, when the developing device 28 is positioned at the developing position, the electrical connection terminal 12 on the developing device 28 side
8 and the electrical connection terminals 130 of the unit frames 14 are electrically connected, and there is no need to perform a specific operation for connecting the electrical connection terminals. On the other hand, move the operating member 112 to arrow 1.
16 (FIG. 5) and position it at the angular position shown in FIG.
(0), the support members 60 and 62 are positioned in the second position shown in FIG. It is held at the separated position shown in FIG. 6 (the position also shown in FIG. 2). At this remote position, since the developing device 28 is located apart from the rotating drum 24, the developer held in the magnetic plan mechanism 82 does not act on the photoreceptor of the rotating drum 24. Also,
When the developing device 28 is thus positioned at the remote position, the electrical connection between the electrical connection terminals 128 and 130 is released, as shown in FIG. 6, and there is no need to perform the above-described operation specific to the release mechanism. The coil spring 134 applies almost no rotational torque to the operating pieces 100 and 102 when they are in the angular position shown in FIG. Applying a large rotational torque, the arrow 11 of the operating member 112
It functions to facilitate turning movement in the direction shown by 6. As shown above, operate the operating member 112 to open the developing device 2.
8 at the developing position, the rotating drum 2
4 can be partially covered by a developing device 28. Therefore,
A corona discharger 36 for removing jams generated on the conveyance path, or a corona discharger 36 for transferring and/or a corona discharger 3 for peeling
By holding the developing device 28 in the developing position during maintenance in step 8, damage to the photoreceptor of the rotating drum 24 can be avoided.
It is possible to prevent toner from scattering. Furthermore, by operating the operating member 112 to position the developing device 28 at a separate position, the distance between the rotating drum 24 and the developing device 28 can be increased. Therefore, the rotating drum 24 and/or the developing device 28 can be easily mounted and removed from the unit frame 14 without damaging the photoreceptor. In a specific example, as shown in FIG. 2, when the upper support frame 10 is placed in the open position, the unit frame 14 is lifted upward and placed in the take-out position, and its upper surface is connected to the lower support frame 6 and the upper support frame. It is directed outward through the space between the bodies 10, and therefore the mounting and dismounting of the rotating drum 24 and/or the developing device 28 can be accomplished more easily.

Further, when the upper support frame 10 is moved from the open position to the closed position while the developing device 28 is in the separated position, the developing device 28 is positioned from the separated position to the developing position. That is, when the upper support frame 10 is pivoted from the open position to the closed position, the unit frame 14 is accordingly pivoted counterclockwise in FIGS. 5 and 6 about the connecting shaft 20. This pivoting movement of the unit frame 14 causes the cam means 120 to act on the operating member 112. When the upper support frame 10 is rotated to the closed position, the unit frame 14 is also positioned at the operating position shown in FIG. 5, and the operation member 112 is moved to the angular position shown in FIG. be rotated. Thus, as described above, the support member 60
and 62 are positioned at the first position, and the development position 2
8 is held at the development position. Further, at this time, the electrical connection terminals 128 and 130 are releasably connected as described above. As is easily understood, when the upper support frame 10 is moved from the open position to the closed position while the developing device 28 is in the developing position, the operating member 112
Since the cam means 120 is in the angular position shown in FIG.
0 is located in the closed position. As described above, by placing the upper support frame 10 in the closed position, the developing device 28 is reliably positioned at the developing position, and therefore, developing defects and the like will not occur.

Although a specific example of an electrostatic copying machine as an example of an image forming apparatus configured according to the present invention has been described above, the present invention is not limited to such a specific example, and there may be no deviation from the scope of the present invention. Various modifications and modifications are possible.

For example, in the specific example shown, a cam means 120 is provided on the support substrate 4 at the rear of the lower support frame 6 in correspondence with the operating member 112, but in addition to these, a lever piece is provided on the support shaft 9. In addition, a cam means acting on the lever piece may be provided on the support base plate 4 in front of the lower support frame body 6. In this case, since the lever piece does not function as an operating section, it can be made shorter than the operating member 112.

[Brief explanation of the drawing]

FIG. 1 is a simplified sectional view showing an example of an electrostatic copying machine as an example of an image forming apparatus according to the present invention in this state with the upper support frame in a closed position. FIG. 2 is a simplified sectional view showing the electrostatic copying machine of FIG. 1 with the upper support frame in an open position. FIG. 3 is a partial perspective view showing a part of the unit frame and the rotating drum attached thereto in the electrostatic copying machine of FIG. 1. FIG. 4 is a perspective view showing the developing device in the electrostatic copying machine of FIG. 1. FIG. 5 is a partially enlarged cross-sectional view showing the electrostatic copying machine of FIG. 1 when the developing device is at the developing position. FIG. 6 is a partially enlarged cross-sectional view showing the electrostatic copying machine of FIG. 1 when the developing device is in a remote position. 2... Housing 6... Lower support frame 10... Upper support frame 14... Unit frame 24... Rotating drum 26... Charging corona discharger 2nd... Developing device 60 and 62...support member 9G...developing device positioning means 100 and 102...acting piece 112...operating member 118...developing position positioning means 120...cam means

Claims (1)

[Claims] 1. A support structure consisting of a lower support frame and an upper support frame attached to the lower support frame so as to be rotatable between an open position and a closed position, and a photoreceptor disposed on the surface. an electrostatic latent image forming means for forming an electrostatic latent image on the surface of the photoreceptor; and a developing device for developing the electrostatic latent image formed on the surface of the photoreceptor; In an image forming apparatus, the developing device is movable between a developing position where the electrostatic latent image is developed close to the image bearing means and a remote position retreating from the developing position; and a developing device positioning means for selectively positioning the developing device at the separated position, and a developing position positioning means for positioning the developing device at the separated position at the developing position by rotating the upper support frame from the open position to the closed position. An image forming apparatus comprising: means. 2. A supporting means is mounted so as to be movable in directions approaching and away from the image carrying means, the developing device is detachably mounted on the supporting means, and the supporting means is attached to the supporting means so as to be movable in the direction approaching and away from the image carrying means. When the developing device is placed in the first position, the developing device is held in the developing position, and the second position separating the supporting means from the image carrying means is
2. The image forming apparatus according to claim 1, wherein the developing device is held at the separated position when the developing device is placed in the separated position. 3. The developing device positioning means includes a working piece that acts on the supporting means and an operating member that moves the working piece,
The developing device is held in the developing position by moving the operating member in a predetermined direction and positioning the support means at the first position via the action piece, and the operating member is moved in a direction opposite to the predetermined direction. 3. The image forming apparatus according to claim 2, wherein the developing device is held at the separated position by moving the supporting means to the second position via the operating piece. 4. The developing position positioning means includes a cam means capable of acting on the operating member, and when the upper support frame is moved from the open position to the closed position when the developing device is in the remote position, 4. The image forming apparatus according to claim 3, wherein the cam means acts on the operating member to move it in the predetermined direction, and the supporting means is positioned at the first position via the operating piece. 5. The support structure includes a unit frame rotatably connected between the lower support frame and the upper support frame, and the image carrying means and the developing device are mounted on the unit frame;
When the upper support frame is in the closed position, the unit frame is held in the working position, and when the upper support frame is in the open position, the unit is lifted upward and placed in the ejection position. The image forming apparatus according to any one of the ranges 1 to 4. 6. The unit frame is provided with an electrical terminal that is releasably connected to an electrical terminal provided on the developing device, and when the unit frame is placed in the operating position, the electrical terminals are connected to each other. 6. The image forming apparatus according to claim 5, wherein the electrical connection of the electrical terminal is released when the unit frame is moved to the take-out position.