JPH05224472A - Image forming device - Google Patents

Abstract

PURPOSE:To always impart proper opening force and to safely and lightly enable opening and closing without causing rapid falling or the like by increasing the opening force with an adjustment means when the gravity of an upper frame is increased by mounting an attachable/detachable member and reducing the opening force when the gravity is reduced by detaching the attachable/ detachable member. CONSTITUTION:The pressurizing force of a pressurizing means 8 imparting the opening force to the upper frame 3 is set so as to be adjustable by the adjustment means 12. The adjustment means 12 is actuated according to the member 7 which can be attached/and detached to/from the frame 3 and it switches the pressurizing force to be two-steps, multisteps and stepless.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a printer, a copying machine and a facsimile.

[0002]

2. Description of the Related Art It is known that an image forming apparatus such as a printer is provided with an upper frame which can be opened and closed with respect to a lower frame.

Generally, the upper frame is applied with a pressing force against the load applied to the upper frame by a spring or the like so that the upper frame can be opened and closed lightly.

One or more of an image carrier, a developing device, a toner accommodating portion, a cleaning unit, and a waste toner recovery tank, which are constituent members of the image forming apparatus process, are formed as one unit, and the image can be attached to and detached from the upper frame. Often used as a forming process unit.

In the construction in which the image forming process unit is detached, the weight acting on the upper frame is greatly increased when the upper frame is opened and closed for maintenance and inspection, and when the image forming process unit is attached to and removed from the upper frame. Fluctuates. If the pressure is set in a heavy state with the process unit attached and the upper frame can be released lightly, opening and closing with the process unit removed causes too much opening force for the upper frame to cause the upper frame to jump up. .. To avoid this problem, if the opening force is set with the process unit removed, the weight will be heavy when the process unit is installed.Therefore, when the upper frame is opened and the hand is released, the upper frame suddenly opens. There is a risk of falling and closing and pinching your hands.

The same problem occurs when an intermediate tray for double-sided image formation, a controller, a paper discharge tray and the like can be attached and detached to the upper frame by an option or the like. Further, when the recording paper on which the image has been formed is placed on the upper frame, the same problem occurs when attempting a jam process in the middle of a large amount of recording. Not only when the image forming apparatus is used by the user as described above, but also when assembling the image forming apparatus on the production line, when the upper frame is assembled to the lower frame with almost only the skeleton, and the outer cover at the final stage. Since the weight of the upper frame is significantly different from that in the assembled state, the operator may apply an unnecessarily force to the opening and closing of the upper frame during the work, which imposes a heavy burden on the operator.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and provides an image forming apparatus that can open and close the upper frame lightly and safely even if the weight acting on the upper frame changes. The challenge is to provide.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems by a lower frame which is fixed in position, and an upper frame which is supported on the lower frame by a support shaft so as to be movable up and down.
In an image forming apparatus having a detachable member on the upper frame and enabling the detachable operation of the detachable member when the upper frame is opened, a pressing unit that exerts an opening force on the upper frame, The image forming apparatus is characterized in that it has an adjusting means for adjusting the pressing force of the pressing means, and the adjusting means is switched to operate by detaching the detachable member.

[0009]

According to the present invention, the pressurizing means for pressurizing the upper frame in the opening / closing direction can adjust the pressurizing force in two steps, multisteps or steplessly by the adjusting means. The adjusting means is operated in accordance with the attachment / detachment of the detachable member such as the image forming process unit detachable from the upper frame or the double-sided image forming intermediate tray. When is large, the pressing force of the pressurizing means is switched so that the pressing force becomes large. Therefore, the pressurizing means is adjusted to an appropriate pressing force according to the change in weight, and the upper frame is always light and can be opened and closed safely.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on the embodiments shown in the drawings.

In FIG. 1, an image forming apparatus such as a printer has a lower frame 1 whose position is fixed, and the lower frame 1
The bracket 1a has an upper frame 3 supported by a support shaft 2 so as to be vertically movable.

Members necessary for image formation in a known manner in an internal space formed by the lower frame 1 and the upper frame 2 in a sealed manner, such as an image carrier, a developing device, a transfer device, a cleaning unit, and a fixing device. An image forming process member is arranged. In FIG. 1, as an example, a recording paper conveyance path 4, a transfer device 5, and a fixing device 6 are provided in the lower frame 1, and an image forming process unit 7 is provided in the upper frame 3.

The upper frame 3 is urged by a pressing means 8, for example, a torsion coil spring, to exert an opening force for rotating upward. A hook 9 is rotatably supported by a hook shaft 10 at an end portion of the upper frame 3, and when the upper frame 3 is in a closed position, the hook 9 is a stop pin 1 provided on the lower frame 1.
1 to prevent the upper frame 3 from opening.

An operator rotates the hook 9 to rotate the hook pin 11
When the engagement with is released, the upper frame 3 can be easily opened.

The upper frame 3 is provided with adjusting means 12 for adjusting the pressure applied by the pressure 8. Adjusting means 12
Is formed as a link 14 rotatably supported on the upper frame 3 by a link shaft 13, for example.
4 rotates about the link shaft 13, and the pin 15 provided at one end of the link 14 changes the position of the end portion of the torsion coil spring 8 to adjust the pressing force. A guide hole 16 for guiding the pin 15 according to the rotation of the link 14 can be provided in the upper frame 3.

The image forming process unit 7 is an image carrier.
For example, all or at least one of the photosensitive drum, the developing device, the toner accommodating portion for the developing device, the cleaning unit for the photosensitive drum, and the waste toner recovery tank for the cleaning unit is one unit, and the other members are the lower frame 1 Can be configured to be located at. The image forming process unit 7 configured as one unit is mounted along the guide rail 17 provided on the upper frame 3 in the direction of arrow A, for example.

In this case, as one example, an engaging bar 18 is movably guided by the guide rail 17 as an engaging means, and the engaging bar 18 and a pin 19 provided on one side (in the figure, provided on the engaging bar 18). ) And the long hole 20 provided on the other side
They are connected to each other by the engagement (provided on the link 14 in the figure).

A guide groove 21 is provided in the engaging bar 18, and when the image forming process unit 7 is mounted, the guide protrusion 25 (FIG. 3) provided in the image forming process unit 7 or the like is engaged.

In a state where the upper frame 3 shown in FIG. 2 is opened and the detachable member 7, for example, the image processing unit 7 is not attached, the pin 15 is pushed by the force of the torsion coil spring 8 and the guide hole 16 Move until it abuts one end. At this time, the link 14 as the adjusting means 12 rotates in the direction opposite to the arrow B in the drawing, and pushes the engagement bar 18 into the guide rail 17 in the direction opposite to the arrow A.

In this state, the angle α formed between the ends of the torsion coil spring 8 which are in contact with the lower frame 1 and the upper frame 3 to be pressed is maximum, and the torsion moment is reduced. Therefore, the opening force acting on the upper frame 3 is small. However, there is no removable member 7,
Since the gravity acting on the upper frame 3 is small, it is just right.

The image forming process unit 7 as a detachable member is mounted in the guide groove 21 of the engaging bar 18 and is rotatably supported by the upper frame 3 by the pin 23 as shown in FIG. The hook 22 is given a force to move to the engagement position by the spring 24, and holds the engagement state at the rear end of the image forming process unit 7 again.

When the image forming process unit 7 is mounted, the engaging groove 1 and the guide protrusion 25 are engaged with each other to engage the engaging bar 1.
8 is pushed in the direction of arrow A, and the link 14 of the adjusting means 12 is pushed.
Is rotated by the action of the pin 19 and the elongated hole 20 in the direction of arrow B in the link shaft 13, and the pin 15 of the link 14 moves in the direction of arrow C to move the end of the torsion coil spring 8. The angle formed by both ends of the screw coil spring 8 is reduced to α ', and the torsion moment is increased. Therefore, the opening force for the upper frame 3 is increased.

2 and 3, when the gravity acting on the frame 3 is small, the pressing force is small, that is, the opening force is small, and when the gravity is large, the pressing force is large, that is, the opening force is large. It becomes possible to switch.

In FIG. 3, when the tip of the second hook 22 is pushed up, the engagement with the image forming process unit 7 is released, and the image forming process unit 7 can be easily pulled out. When removed, it changes to the state shown in Fig. 2.

In contrast to the example in which the detachable member shown in FIGS. 1 to 3 is the image forming process unit 7, the detachable member may be the double-sided image forming intermediate tray 31 as shown in FIG. The intermediate tray 31 is positioned and placed on the upper surface of the upper frame 3, and the intermediate tray 31 is engageably placed so as not to drop off when the upper frame is opened for jam processing or the like. Is formed as. Therefore, for example, a concave portion 32 having an inclined surface is formed, and a convex portion 33 that engages with the concave portion 32 is formed on the intermediate tray 31. Further, a protrusion 34 is formed in the concave portion 32, and a hole 35 into which the protrusion 34 is fitted is formed in the convex portion 33.

Pressurizing means 8 for applying an opening force to the upper frame 3.
Since the adjusting means 12 can be formed in the same manner as in the example of FIG. 1,
Components corresponding to those in FIG. 1 are designated by the same reference numerals, and description thereof will be omitted.

The upper frame 3 is provided with a circulating transport path 36 for transporting the recording paper after being fixed by the fixing device 6 to the intermediate tray 31, and a reversing transport path 37 for reversing and transporting the recording paper from the intermediate tray 31 to the transfer position by the transfer device 5. It

The intermediate tray 31 may be provided with a paper discharge path 38 for discharging the recording paper after recording, in addition to the conveying path for temporarily storing the recording paper for double-sided image formation.

A lever portion 40 having a cam surface 39 at the tip thereof is formed as an engaging means on the intermediate tray 31.

When the intermediate tray 31 is placed from above as shown in FIG. 4, the cam surface 39 of the lever portion 40 is adjusted by the adjusting means 1.
Abutting on the end of the link 14 as 2, the link 14 is rotated around the link shaft 13 in the direction of the arrow B,
The pin 15 of 4 moves the end of the torsion coil spring 8 in the direction of arrow E, and increases the torsion moment of the torsion coil spring 8. Therefore, the opening force acting on the upper frame 3 is increased, and the intermediate tray 31 can be placed and lightly opened and closed even if the gravity is increased.

The intermediate tray 3 with the upper frame 3 closed.
When 1 is removed, the contact of the cam surface 39 with the link 14 is released, and the link 14 is rotated in the direction opposite to the arrow B by the force of the torsion coil spring 8. Therefore, the torsion moment of the torsion coil spring 8 is reduced, and the upper frame 3
The opening force that acts on is reduced. Since the intermediate tray 31 is eliminated and the gravity of the upper frame 3 is reduced, the opening force is also reduced, so that the opening force is prevented from being too strong and splashing.

When the upper frame cover 41 is attached to the upper frame 3 instead of the intermediate tray 31, a portion to be placed on the upper frame 3 of the upper frame cover 41 is configured similarly to the intermediate tray 31 as shown in FIG. Then, similarly to the case of FIG. 4, when the upper frame cover 41 is mounted, the opening force of the upper frame 3 is made large, and when the upper frame cover 41 is removed, the opening force of the upper frame 3 is made small in two stages. 4, which are the same as or correspond to those in FIG. 4, are denoted by the same reference numerals and detailed description thereof will be omitted.

The opening force of the upper frame 3 can be switched by attaching and detaching the upper frame cover. Particularly, by changing the opening force before and after assembling the upper frame cover 41 during the assembly work, the upper frame 3 during the assembly work can be changed. Opening and closing work can be done easily in any state, and workability can be improved.

When the discharge tray 42 is provided on the upper frame 3 or the upper frame cover 41 attached to the upper frame 3 as shown in FIG. 6, when a large amount of recording paper is recorded, a jam process is performed on the way. Therefore, when the upper frame is opened, the gravity becomes large, and when the hand is released, it suddenly drops and closes, and there is a risk of pinching the hand. Therefore, the discharge tray 42 is supported by a tray shaft 43 so as to be vertically rotatable,
The link 1 as the adjusting means 12 is provided at the tip of the paper discharge tray 42.
Lever portion 40 having a cam surface 39 that abuts on the end of
Are provided as engaging means.

Recording paper 4 discharged by paper discharge roller 44
5 are stacked on the paper discharge tray 42, and the paper discharge tray 42 gradually descends and rotates according to the weight of the recording paper 5. In accordance with this downward rotation, the contact point between the cam surface 39 and the link 14 changes, and the link 14 gradually moves around the link shaft 13 by the arrow B.
Is rotated in the direction of.

In accordance with the rotation of the link 14, the pin 15 gradually pushes and moves the end of the torsion coil spring 8, and the torsion moment of the torsion coil spring 8 is gradually increased.

Therefore, if the spring constant of the torsion coil spring and the rotation angle of the link 14 according to the weight of the recording paper 45 are selected in advance, the torsion coil spring will have an appropriate opening force according to the weight at that time. 8 can support the upper frame 3. In this case, the opening force can be changed steplessly. If necessary, the opening force can be adjusted by rotating the link 14 in multiple steps instead of steplessly.

When the paper discharge tray 42 is constructed so as to be completely removed from the upper frame 3, it can be considered to be included in the range of removable members in the present invention even when it is not completely removed.

4 to 6 show an example in which a detachable member is provided on the upper side of the upper frame 3, the upper frame cover 41 is removed as shown in FIG. The present invention can be applied to a case where a member to be fitted in from above, for example, the controller 51 is provided. The controller case 52 in which the controller 51 is inserted is provided with the lever portion 40 having the cam surface 39 as in the example of FIG. 4, and the controller case 52 is mounted to rotate the link 14 in the same manner as in the example of FIG. Increase the torsional moment of the spring 3 and increase the opening force. When the controller case 52 is removed, the link 14 returns to its original state, and the torsion moment of the torsion coil spring 8 is reduced and the opening force is weakened.

The above-mentioned embodiments can be implemented independently, but a plurality of embodiments can be implemented simultaneously.

For example, the opening force of the upper frame can be switched according to both attachment / detachment of the image forming process unit and attachment / detachment of the intermediate tray. In this case, it is possible to switch to two levels of strength and weakness, or to switch to multiple levels depending on the weight of the removable member.

When there are a plurality of detachable members, the opening force can be switched according to the detachment of only the member having the greatest influence.

The pressurizing means for the upper frame is not limited to the spring shown in the figure, and may be any one as long as the force can be changed. The adjusting member is not limited to the link in the figure, and may be mechanical, electrical or Hydraulic means can be used.

[0044]

As described above, according to the present invention, the adjusting member is operated in a two-step, multi-step, or stepless switching operation in accordance with the attachment / detachment of the detachable member to constantly switch the pressure applied to the upper frame to an appropriate force. The upper frame can be opened and closed lightly at all times, and it has been prevented from falling suddenly due to gravity and from jumping up due to excessive opening force.

According to the present invention, since the opening and closing work of the upper frame is safe and easy, the workability at the time of maintenance and inspection and assembly is improved.

[Brief description of drawings]

FIG. 1 is an overall schematic view of an image forming apparatus according to the present invention when it is closed.

FIG. 2 is a partial view showing a state where the upper frame of FIG. 1 is opened and an image forming process unit is detached.

FIG. 3 is a partial view showing a state in which the upper frame of FIG. 1 is opened and an image forming process unit is attached.

FIG. 4 is an overall schematic view of the image forming apparatus when the intermediate tray for double-sided image formation is mounted on the upper side when the image forming apparatus is closed.

FIG. 5 is an overall schematic view of the image forming apparatus when closed, showing a state in which an upper arm exterior cover is attached.

FIG. 6 is an overall schematic view of an image forming apparatus provided with a vertically movable paper discharge tray.

FIG. 7 is an overall schematic diagram of an image forming apparatus in which a controller is mounted from above.

[Explanation of symbols]

 1 Lower Frame 2 Spindle 3 Upper Frame 7 Detachable Member (Image Forming Process Unit) 8 Pressurizing Means (Spring) 12 Adjusting Means (Link)

Claims (5)

[Claims] 1. A lower frame that is fixed in position, an upper frame that is supported by a support shaft so as to be able to open and close vertically, and a member that can be attached to and detached from the upper frame. An image forming apparatus capable of performing a detaching operation of the detachable member at the time of opening, comprising: a pressing unit that exerts an opening force on the upper frame; and an adjusting unit that adjusts a pressing force of the pressing unit, An image forming apparatus, wherein the adjusting means is switched to operate by detaching the detachable member. 2. The removable member is at least one of an image carrier, a developing device, a toner accommodating portion for the developing device, a cleaning unit for the image carrier, and a waste toner collecting tank of the cleaning unit. Is formed as an image forming process unit detachably formed on the upper frame as one unit, and the image forming process unit is provided with engaging means for engaging the adjusting means, and the image forming process unit is mounted. When the image forming process unit is detached, the adjusting means is disengaged from the engaging means when the image forming process unit is removed. The image forming apparatus according to claim 1, wherein the pressing force of the pressure means is switched to a small value. 3. The member which is attachable / detachable and comprises at least one of an intermediate tray for double-sided image formation, a paper discharge tray, an upper frame cover, and a controller, and is placed on or mounted on the upper frame. Formed as
The member is provided with engaging means, and the engaging means releases the adjusting member when the detachable member is detached, and engages the adjusting member when the detachable member is attached to form the adjusting member in two stages. 2. The image forming apparatus according to claim 1, wherein the adjusting member switches and adjusts the pressing means with a large force when engaged and with a small force when released. 4. The discharge tray is formed so as to be movable up and down according to the amount of sheets to be placed, and the vertical movement of the discharge tray is transmitted to the adjusting means by the engaging means, and the pressurizing means. The image forming apparatus according to claim 3, wherein the pressing force of the image forming apparatus can be adjusted steplessly. 5. The pressing means is formed as a torsion spring, and the adjusting means is formed as a rotatable lever,
The lever is rotated by engagement of the engagement means to change the spring force of the torsion spring.
The image forming apparatus according to any one of 4 above.