JPH11265104A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device having good operability, capable of accurately forming an image without adjusting the repulsive force of a damper and also without adjusting the installation position of the damper based on an image forming state. SOLUTION: Provided that the centroid of the main body upper part 100 stands at a position G and the repulsive force (force of pushing up the main body upper part 100) of the dampers 60 and 62 is expressed by F2 and F1 respectively, the upper end parts 60a and 62a of the dampers 60 and 62 are fixed across the centroid G in an opposed direction. And also, the upper end part 60a is fixed at a distance L2 from the centroid G, and the upper end part 62a is fixed at a distance L1 from the centroid G. Besides, a relation between the repulsive force F1 and F2 and the distances L1 and L2 is controlled so as to satisfy F1:F2=L2:L1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image forming apparatus such as a copying machine, a printer, and a plotter.

[0002]

2. Description of the Related Art As an output device of a computer or a work station, an ink jet type image forming apparatus for forming an image on a recording medium by discharging ink, or an electrophotographic type forming apparatus for forming an image on a recording medium using a developer or the like. Image forming apparatuses are known. These image forming apparatuses include an image forming unit on which an image is formed. Further, the image forming apparatus is generally provided with a paper feed unit for feeding a recording medium to the image forming unit, and a discharge unit formed on the opposite side of the image forming unit from the paper feed unit, A recording medium transport path for transporting the recording medium in a direction from the paper supply unit to the discharge unit is formed.

In the image forming apparatus, a rotating shaft is formed at one end (rear part of the main body) in a direction perpendicular to the recording medium conveying path, and an opening / closing part (front part of the main body) opposite to the one end is formed. There is a type (so-called crocodile type) that can be opened and closed to divide the apparatus main body into an upper body and a lower body. This alligator type image forming apparatus is configured such that when the opening / closing portion is opened, the recording medium transport path is largely exposed,
Paper jam (jam) can be easily handled by the user.

The above-mentioned alligator-type image forming apparatus of the electrophotographic type generally has an optical system and a photosensitive drum built in an upper part of a main body, and a cassette tray and a fixing device are built in a lower part of the main body. I have. The lower part of the main body is fixed, and the part of the upper part of the main body that is open,
The air and the like are configured to be pushed up by a sealed damper.

[0005] As the dampers, two dampers which are arranged at a predetermined distance from each other are usually used, and their upper ends are fixed to the front part of the upper part of the main body. The lower part is fixed to the front part of the main body. The repulsive force of these two dampers pushes up the main body front side portion of the main body upper part around the rotation axis of the main body rear part, and is divided into the main body upper part and the main body lower part.

In the crocodile-type image forming apparatus described above, the opening and closing portion of the front portion of the main body is closed except for the jam processing. In order to close the opening / closing portion in this way, two hooks that suppress the repulsive force of the two dampers described above may be used. Each of the two hooks is arranged near the two dampers, and the upper end of the hook is fixed to the upper part of the main body. On the other hand, the lower end of the hook is shaped to be hooked on a hook hole formed by a hole of a sheet metal provided at a lower portion of the main body. When the user pushes down the upper part of the main body which is pushed up by the damper, the lower end of the hook is hooked on the hook hole, and the opening / closing part of the front part of the main body is closed, and the apparatus enters a standby state in which an image can be formed.

[0007]

In an electrophotographic image forming apparatus, the positional accuracy of the optical system is important in order to accurately read an image on a document with an optical system and form an accurate image. However, depending on the position where the two dampers are arranged, when the upper part of the main body is pushed up, the upper part of the main body is slightly twisted, and as a result, the positional accuracy of the optical system may be deteriorated. In this case, an accurate image cannot be formed. In order to form an accurate image, it is necessary to adjust the repulsive force of the damper and adjust the mounting position of the damper, which makes the image forming apparatus inconvenient.

As described above, when the upper part of the main body pushed up by the damper is pressed down, the lower ends of the hooks are caught in the hook holes. I have. However, when, for example, the end of the upper portion of the main body is pushed down, only the lower end of one of the two hooks may be caught in the hook hole. Such a state is called one-sided tightening, and the positional accuracy of the optical system deteriorates, and the upper portion of the main body may be suddenly opened during image formation. Therefore, in the case of one-sided tightening, an accurate image cannot be formed. In order to prevent this one-sided tightening, the upper part of the main body needs to be pushed down with sufficient care, resulting in an inconvenient image forming apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a user-friendly image forming apparatus in view of the above circumstances.

[0010]

According to a first aspect of the present invention, there is provided a first image forming apparatus in which a recording medium is fed from a paper feeding section to a discharge section opposite to the paper feeding section. A recording medium transport path on which a recording medium is transported, and an opening / closing section opposite to the one end with respect to a rotation axis formed at one end in a cross direction intersecting the recording medium transport. In the image forming apparatus which is divided into two parts, an upper part of the main body and a lower part of the main body by opening, (1) an upper end part is fixed to a part of the upper part of the main body on the side of the opening and closing part and the opening and closing of the lower part of the main body (2) the two dampers, the lower ends of which are fixed to the part-side part, which hold the opening / closing part opened by pushing up the upper part of the main body;
The upper end of each of the two dampers is fixed at a position away from the center of gravity by a distance L1 and a distance L2 in opposite directions with respect to the center of gravity of the upper part of the main body. The relationship between a repulsive force F1 that pushes the upper part of the main body by a damper that is a distance L1 away from the main body and a repulsive force F2 that pushes the upper part of the main body by a damper that is a distance L2 from the center of gravity satisfies F1: F2 = L2: L1. It is characterized by having.

Here, the two dampers have (3) a late repulsion force when closing the opening / closing section is greater than an initial repulsion force when closing the opening / closing section by pressing down the upper portion of the main body. The repulsive force may be set so as to be strong.

[0012] The two dampers may include: (4) the upper end portion of the two dampers, the one having the stronger repulsive force;
It may be fixed to a side closer to the rotation axis than the upper end having the weaker repulsion.

According to a second image forming apparatus of the present invention for achieving the above object, the recording medium is moved in a direction from a paper feeding section to which the recording medium is fed toward a discharge section opposite to the paper feeding section. A main body having a recording medium conveyance path to be conveyed, and opening and closing an opening / closing part opposite to the one end with respect to a rotation axis formed at one end in a cross direction intersecting the recording medium conveyance path; (5) In the image forming apparatus divided into two parts, an upper part and a lower part of the main body, (5) an upper end part is rotatably fixed to a part of the upper part of the main body on the side of the opening and closing part and has an L-shape at each lower end part. (6) a hook roller fixed to a lower portion of the main body, on which the hook portion of the hook is hooked, and (7) the hook roller; Covering the outer peripheral surface of
A cylindrical collar rotatable in the circumferential direction of the hook roller.

Further, the hook may be configured such that (8) a slope inclined downward toward the outside is formed at a tip portion of the hook portion of the hook.

Still further, the hook is located at a position above the contact surface of the hooking portion that contacts the collar and is separated from the contact surface by a distance longer than an outer diameter of the collar. May be formed with a projection.

Further, the hook roller may be as follows:
The center axis of the hook roller may be eccentric.

Further, the image forming apparatus may further comprise: (11) a side portion of the lower portion of the main body, which is rotatably fixed to the paper feeder side and extends in a cross direction intersecting the recording medium conveyance path; 12) The gap formed between the upper part of the main body and the lower part of the main body in a state where the opening / closing part is opened and pushed up is located near the gap on the side of the paper feeding part, and is opposite to the one side part. Having other sides extending in the cross direction,
(13) A rectangular shape on which a recording medium conveyed to the recording medium conveyance path is placed in a use mode in which the one side is a rotation axis and the other side is rotated downward and stopped. May be provided.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a copying machine as an embodiment of the image forming apparatus of the present invention.

On the top surface of a copying machine (which is an example of an image forming apparatus according to the present invention) 10, an original cover plate 12 which can be opened and closed is arranged. On the front side of the top surface, an operation panel display 14 for inputting the number of copies and the like is arranged.
The copying machine 10 is provided with a universal cassette 16 for accommodating a plurality of cut sheets so that the universal cassette 16 can be taken in and out from the front side of the copying machine 10. The right side wall of the copying machine 10 is provided with a rectangular manual tray 18 (see FIG. 2) capable of feeding small-size recording paper such as postcards.
As shown in FIG. 2, the manual feed tray 18 is
It rotates in the direction of arrow C around the center 8a, and opens to the position where the recording medium can be placed (the position indicated by the two-dot chain line). The left side wall of the copying machine 10 is provided with a paper discharge tray 20 on which recording paper on which an image is formed is stacked.

At the front of the copier 10, a rectangular front door 22 is provided.
However, it is fixed so that it may open to the near side with the lower side portion 22a as the center of rotation. By opening the front door 22, the inside of the copier 10 can be observed. With the front door 22 kept open, a pair of dampers 60, 62 (see FIG. 3) is removed by removing a pair of hooks 50, 52 (see FIGS. 3 and 4) disposed near the front door 22. 4 (see FIG. 4), the front side of the upper part of the main body of the copying machine 10 (the part where the optical system 28 and the photosensitive drum 32 shown in FIG. 2 are incorporated) is pushed up. As a result, the copying machine 10 is divided into an upper body and a lower body (a part in which the universal cassette 16 and the like are incorporated).

Referring to FIG. 2, a procedure for forming an image by the copying machine 10 of FIG. 1 will be described.

FIG. 2 is a schematic diagram showing an outline of the internal structure of the copying machine 10. As shown in FIG. 2, the same components as those of FIG. 1 are denoted by the same reference numerals.

An original platen glass 26 on which the original 24 is placed is arranged below the original cover 12. The original 24 is placed on the original platen glass 26 so that the image surface faces downward, and the original 24 is pressed and fixed by the original cover 12. The image recorded on the document 24 is read by a well-known optical system 28 having a light source lamp (not shown) or the like, and light (broken line A) carrying information of the image recorded on the document is obtained.
This light is applied to the photosensitive drum 32 uniformly charged by the charging unit 30 to form an electrostatic latent image. This electrostatic latent image is developed with the developer (toner) supplied from the developing unit 34 to form a developed image. On the other hand, a recording medium such as recording paper sent from the universal cassette 16 is fed in the direction of arrow B, and the developed image is transferred to the recording medium in the transfer unit 36.

The recording medium onto which the developed image has been transferred
The sheet is conveyed to the fixing unit 40 by 8. A heat roller 42 and a press roller 44 are arranged in the fixing unit 40,
The recording medium is conveyed while being sandwiched between these two rollers 42 and 44, and the developed image is fixed on the recording medium. The recording medium on which the developed image has been fixed in this manner is discharged and stacked on the discharge tray 20. After the transfer, the photosensitive drum 3
2 is scraped off by the cleaning device 46. In addition, the recording medium can be fed from the manual feed tray 18, and the procedure for forming an image on the recording medium fed from the manual feed tray 18 is the same as described above.

Referring to FIGS. 3 and 4, the upper part of the copying machine is pushed up, and the copying machine is moved into two parts by the upper part and the lower part of the body.
The state of division will be described.

FIG. 3 is a perspective view showing the copier with the front door opened, and FIG. 4 is a perspective view showing the copier with the front door opened and the upper part of the main body of the copier pushed up. In these figures, the same components as those shown in FIGS. 1 and 2 are denoted by the same reference numerals.

In the copying machine 10, the universal cassette 1
The recording medium sent from 6 is conveyed to the inside of the copying machine 10 from the paper supply unit 70 on the right side of the paper surface of FIGS.
The recording medium on which the image is formed by the copying machine 10 is discharged to the discharge tray 20 from the discharge unit 72 on the left side of the paper surface of FIGS. As described above, the copying machine 10 is formed with the recording medium transport path in which the recording medium is transported in the direction from the paper feeding unit 70 to the paper discharging unit 72.

The copying machine 10 is divided into an upper body 100 (a part in which the optical system 28 and the photosensitive drum 32 shown in FIG. 2 are incorporated) and a lower body 200 (a part in which the universal cassette 16 and the like are incorporated). When the pair of dampers 60 and 62 push up the front part of the main body upper part 100, the opening / closing part 74 of the front part of the copying machine 10 is opened. The damper 60 is located near the paper feeding unit 70 and
0 is located in the front part. Also, the damper 62
It is located near the paper discharge unit 72 and at the front side of the copying machine 10.

The opening and closing portion 74 is opened and closed about a rotation shaft 76 formed on a main body rear plate 77 (see FIG. 8) located at a rear portion of the copying machine 10. The opening / closing part 74 and the rotation shaft 76 are formed at one end in the cross direction intersecting the recording medium transport path and the other end opposite to the one end. The pair of dampers 60 and 62 are fixed at predetermined positions, which will be described later with reference to FIG.

A hook 50 is disposed on the left side of the damper 60 in the drawing, and a hook 52 is disposed on the right side of the damper 62 in the drawing. As will be described later, these hooks 50 and 52 are hooked on hook rollers 90 (see FIGS. 9 and 10) attached to the lower part 200 of the main body, thereby overcoming the repulsive force of the dampers 60 and 62 and closing the opening / closing section 74. Keep in the state.

Referring to FIG. 5 and FIG.
8 will be described.

FIG. 5 is a perspective view showing a state in which the user is trying to close the opening / closing section 74 while holding the manual feed tray 18 by hand. FIG. 6 shows that the manual feed tray 18 held by the user rotates naturally. It is a perspective view which shows the state which performs. In these figures, the same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals.

The manual feed tray 18 has a rectangular shape.
The one side portion 18a extends in a direction substantially orthogonal to the recording medium transport path, and is rotatably fixed to a side wall of the lower portion 200 on the side of the sheet feeding unit 70. Also, the manual feed tray 18
The other side 18b opposite to the side 18a also extends in a direction substantially orthogonal to the recording medium conveyance path.

By the way, a gap 78 is formed near the sheet feeding section 70 by the upper body 100 and the lower body 200 in a state where the opening / closing section 74 is opened and pushed up. As shown in FIG. 5, if the user tries to close the open opening / closing section 74 while closing the manual feed tray 18 and inserting the hand 80 into the gap 78, the hand 80 is likely to be pinched by mistake. However, since the side portion 18a of the manual feed tray 18 is rotatably fixed to the lower portion 200 of the main body, the manual feed tray 18 is pushed down by the hand 80 and rotates around the one side portion 18a in the direction of arrow C. Therefore, the upper body 100 and the lower body 20
The hand 80 is not pinched between 0.

Referring to FIGS. 7 and 8, a pair of dampers 60,
The positional relationship of 62 will be described.

FIG. 7 is a front view of the copying machine schematically showing fixed positions of the dampers 60 and 62. FIG. 8 is a right side view of FIG.

As described above, the upper ends 60a and 62a of the dampers 60 and 62 are fixed to the upper part 100 of the main body.
The lower ends 60b and 62b are fixed to the main body lower part 200. When the distance from the position of the center of gravity to the dampers located on the left and right is equal, the repulsion force of the two dampers may be simply made equal. However, when providing a compact and easy-to-use copying machine, It is difficult to make the distance to the damper equal. In the case of the present invention, the dumper on the paper discharge tray side is moved near the center of the main body so that the user can easily take out the copy sheets stacked on the paper discharge tray. Here, it is assumed that the center of gravity of the main body upper portion 100 is at the position G. Further, repulsive forces (forces for pushing up the upper portion 100 of the main body) of the dampers 60 and 62 are defined as F2 and F1, respectively.

As shown in FIG. 7, the upper ends 60a, 62a of the dampers 60, 62 are fixed in opposite directions with respect to the center of gravity G. The upper end 60a is fixed at a distance L2 from the center of gravity G, while the upper end 62a is fixed at a distance L1 from the center of gravity G.
Here, the relationship between the distances L1 and L2 and the repulsive forces F1 and F2 is configured to satisfy F1: F2 = L2: L1. For this reason, the torque received by the two dampers 60 and 62 on both sides of the center of gravity G of the upper body 100 is equal.

Therefore, not only when the opening / closing section 74 is open, but also when the opening / closing section 74 is closed and an image can be formed, the two portions on both sides of the center of gravity G of the main body upper portion 100 are provided.
The two dampers 60 and 62 receive an equal torque. Therefore, even when the opening / closing section 74 is closed and an image can be formed, the main body upper portion 100 is not twisted, and the main body upper portion 10 is not twisted.
The frame of the optical system incorporated in the lens 0 does not twist. As a result, there is no error in the optical system due to the twist of the upper body 100, and an accurate image can be formed.
That is, the above-mentioned F1: F2 = L2: L1 can be satisfied without adjusting the repulsive force of the dampers 60, 62 or adjusting the mounting positions of the dampers 60, 62 based on the image forming state. As a result, an accurate image can be formed, and the copying machine 10 with good usability can be obtained.

The repulsive force of the two dampers 60 and 62 will be described.

These two dampers 60 and 62 have a stronger repulsion force at the end of closing the opening / closing section 74 than an initial repulsion force at the start of closing the opening / closing section 74 by pressing down the upper portion 100 of the main body. Is set to For example,
Initial repulsion is 5kgf, late repulsion is 10kg
f. By setting the repulsive forces of the two dampers 60 and 62 to gradually increase in this way, when the user closes the opening / closing section 74, the opening / closing section 74 does not weaken halfway and closes vigorously. No operability is obtained. The repulsive forces F2, F1 of the two dampers 60, 62 are set such that the upper body 100 is pushed up to a predetermined position. Therefore, the upper body 10
There is no possibility that the opening / closing section 74 does not open due to losing its own weight of zero.

The upper ends 60 of the dampers 60, 62
a and 62a are fixed to a fixing tool (not shown) fixed to the front side plate of the main body upper part 100 with bolts or the like. The position where this fixture is fixed to the front side plate of the upper part 100 of the main body with bolts or the like is usually the same position for the right and left dampers as viewed from the side. However, in the present embodiment, when the upper end portion 62a of the damper 62 having a strong repulsive force F1 is fixed to a portion away from the front side plate, the fixing tool may be deformed and the upper body 100 may be twisted. Therefore, the upper end portion 62a of the damper 62 is fixed to a side closer to the front plate than the upper end portion 60a of the damper 60 to prevent deformation of the fixture (see FIG. 8). For example, the upper end portion 62a is fixed to a side closer to the front side plate of the upper part of the main body by about 7 ° with respect to a perpendicular passing through the lower end portion 62b.

Referring to FIG. 9 to FIG.
0, 52 and the hook roller 90 will be described.

First, a state in which the hook is hooked on the hook roller will be described with reference to FIG. FIG. 9 is a schematic view of the copying machine 10 exaggerating the hooks. In this figure,
The same components as those in FIGS. 1 to 8 are denoted by the same reference numerals.

The hooks 50 and 52 are, as shown in FIG.
It is arranged in parallel with the dampers 60 and 62. Hook 5
The upper ends 50a and 52a of the reference numerals 0 and 52 are rotatably fixed to the opening / closing part 74 side of the upper part 100 of the main body. L-shaped hooks 50b, 5 are provided at the lower ends of the hooks 50, 52, respectively.
2b is formed. An inclined surface 50 inclined downward toward the outside is provided at the tip of the hooks 50b and 52b.
c, 52c are formed.

The hooks 50 of these hooks 50, 52
Since each of b and 52b is hooked and locked by the hook roller 90, the opening / closing section 74 can be kept closed by overcoming the repulsive force of the dampers 60 and 62. Release lever 5
4 in the direction of arrow D, the two hooks 5
The locks 0 and 52 rotate in the direction of arrow D in conjunction with each other to release the lock, and the upper body 100 is pushed up by the dampers 60 and 62 (see FIGS. 7 and 8).

The configuration of the hook roller will be described with reference to FIGS.

FIG. 10 is a perspective view showing a state where the hook rollers are attached to the support table, and FIG. 11 is a perspective view showing a state where the collar is disassembled from the hook rollers.

The hook roller 90 is fixed to a support base 96 fixed to the bottom plate of the lower part 200 of the main body. The hook roller 90 has a columnar shape and has a hook roller shaft for eccentrically rotating the hook roller at both ends thereof. The hook roller shaft 92 projects from the support table 96 and is rotatably fixed to the support table 96. A screw is formed on the outer peripheral surface of the hook roller shaft 92, and is fixed to the support base 96 by being screwed into a nut (not shown). As described above, the hook roller 90 can be eccentrically rotated. For this reason, hook 50,
The position of the main body upper portion 100 (see FIG. 9) hooked on the hook roller 90 by the 52 is not fixed but changed.

The hook roller 90 is eccentric as described above,
The reason why the position of the upper part of the main body can be adjusted will be described.

When the two hooks 50 and 52 are locked by the hook rollers 90 and 90, respectively,
(See FIG. 7) is closed, and the image can be formed. Therefore, the upper body 100 and the lower body 200 have a predetermined positional relationship. However, this positional relationship may not be predetermined due to the tolerance of a plurality of parts. In this case, by loosening the nut and rotating the hook roller shaft 92, the hook roller 9 is rotated.
Since the distance between the main body upper part 100 and the main body lower part 20 can be changed even if there are tolerances in a plurality of parts.
0 can be a predetermined positional relationship.

The outer peripheral surface of the hook roller 90 is covered with a cylindrical collar 94 rotatable in the circumferential direction. However, the outer diameter of the hook roller 90 and the inner diameter of the collar 94 are almost the same, and the collar 94 is almost fitted to the hook roller 90, so that there is little backlash. The reason why the outer peripheral surface of the hook roller 90 is covered with the rotatable collar 94 will be described with reference to FIGS.

FIG. 12 is an exaggerated schematic diagram showing one-sided tightening with only one of the two hooks hooked on the hook roller. FIG. 13 is an enlarged schematic view showing a hook portion of the hook hooked on the hook roller. 12 and 13, the same components as those in FIGS. 1 to 11 are denoted by the same reference numerals.

As described above, the two hooks 50 and 52 for suppressing the repulsive force of the two dampers 60 and 62 are connected to the damper 6.
When the upper part 100 of the main body, which is pushed up by 0, 62, is pushed down, the hooks 50a, 52
aThe lower end is adapted to be hooked on the hook roller.
However, when the right end of the upper part 100 of the main body is depressed, for example, as shown in FIG.
In some cases, only the hook portion 50a of one of the hooks 50 is hooked on the hook roller 90. Such a state is called one-sided tightening, and the positional accuracy of the optical system 28 (see FIG. 2) is deteriorated. Therefore, in the case of one-sided tightening, an accurate image cannot be formed.

In such a case where the hook roller 90 is likely to be tightly tightened, the hook 50 cannot rotate to a fixed position where the hook roller 90 is hooked unless the hook 52 is hooked on the hook roller 90, and the hook roller 90 is positioned on the inclined surface 50 c of the hook 50. The hook roller 90 is provided with a collar 94 located on the outer periphery thereof.
Is easily rotated, so that there is no sliding resistance. Therefore, the hook 50a easily comes off the hook roller 90, and the upper part 100 of the main body is pushed up by the dampers 60, 62. For this reason, one-sided tightening can be easily prevented, and a user-friendly copying machine 10 can be obtained. In addition, since the inclined surface 50c is formed, the hook portion 50b is easily detached from the hook roller 90 at the time of single tightening. For this reason, one-sided tightening can be more reliably prevented.

When the user operates the release lever for jam clearance or the like, since the collar 94 is attached to the hook roller 90 even when the hooks 50 and 52 are operated, the sliding resistance of the hooks 50 and 52 is extremely low. Small and can be operated with light power. Furthermore, when the jam treatment is finished, the upper part 100 is pushed down and the hooks 50 and 52 are hooked on the hook rollers 90. Similarly, by rotating the collar 94, the hooks 50 and 52 can be easily set and the operability is good.

Further, a low projection 50d is formed above the inclined surface 50c. The projection 50d is connected to the hook 5
This is to prevent the hook portions 50a, 52a from coming off from the hook rollers 90 due to vibration or the like when the hook portions 50a, 52a of 0, 52 are normally hooked to the hook rollers 90 instead of one-sided tightening.

By the way, as shown in FIG.
A protruding portion 50e is formed above the contact surface of the hook portion 50b that abuts on the collar 94 and away from the contact surface by a distance longer than the outer diameter of the collar 94. Therefore, a gap of a distance L3 is formed between the collar 94 and the protruding portion 50e. For this reason, when pressing down the upper part 100 of the main body (see FIG. 12),
Of the hooks 50 and 52,
0e abuts on the collar 94 and the upper part 100 of the main body does not fall. As a result, it is possible to prevent a trouble that the upper body 100 cuts into the lower body 200 and breaks them. Further, since a gap of a distance L3 is formed between the collar 94 and the protruding portion 50e, the hook 90 and the collar 94 are easily caught by the hook portion 50a. In addition, hook 5
2 has the same shape and exhibits the same operation and effect.

Referring to FIG. 14, a modified example of the hook roller and the support base will be described.

FIG. 14A is an enlarged perspective view showing a part of the support table, FIG. 14B is a sectional view of the hook roller and the support table, and FIG. 14C is a perspective view showing the hook roller and its mounting plate. FIG.

As described above with reference to FIGS. 10 and 11, when the two hooks 50 and 52 are engaged with the hook rollers 90 and 90, respectively, the opening / closing portion 74 (see FIG. 7) is closed. The main body upper portion 100 and the main body lower portion 200 have a predetermined positional relationship. In this case, the hook roller shaft 92 and the eccentricity of the hook roller 90 are used in the examples shown in FIGS. 10 and 11 so that the upper body portion 100 and the lower body portion 200 can have a predetermined positional relationship even if a plurality of parts have tolerances. The hook roller 90 and the upper body 100
(See FIG. 9).

Here, the hook roller 190 (the hook roller of this example is not eccentric) in which the hook roller shaft 192 is located at the center axis is mounted on the mounting plate 194, and the mounting plate 194 is fixed to the support base 196. An elongated hole 196a extending in the vertical direction is formed in the support base 196,
The tapped holes 194a of the mounting plate 194 are aligned with the elongated holes 196a and fixed with bolts 198. The position where the mounting plate 194 is fixed to the support 196 is moved by the length of the long hole 196a. Therefore, even if there are tolerances in a plurality of parts, the upper body portion 100 and the lower body portion 200 can have a predetermined positional relationship.

[0064]

As described above, in the first image forming apparatus of the present invention, the dampers are respectively disposed at the positions L1 and L2 away from the center of gravity in opposite directions with respect to the center of gravity of the upper part of the main body. Since the relationship between the repulsive force F1 of the damper pushing the upper part of the main body by the damper at a distance L1 from the center of gravity and the repulsive force F2 of the damper pushing the upper part of the main body at the distance L2 from the center of gravity satisfies F1: F2 = L2: L1, The torque received by the two dampers on both sides of the center of gravity G at the top of the main body is equal. Therefore, the upper part of the main body is not twisted, and the frame of the optical system incorporated in the upper part of the main body is not twisted. As a result, there is no error in the optical system due to the twist of the upper part of the main body, and an accurate image can be formed. That is, an accurate image can be formed without adjusting the repulsive force of the damper based on the image forming state or adjusting the mounting position of the damper, so that a user-friendly image forming apparatus can be obtained.

Here, the two dampers have a repulsive force such that the repulsive force in the latter stage of closing the opening / closing portion is stronger than the initial repulsive force in the case where the upper portion of the main body is pushed down to start closing the opening / closing portion. When the setting is made, an image forming apparatus with good operability when opening and closing the opening and closing unit can be obtained.

In the case where the two dampers are such that the upper end of the two dampers having the higher repulsive force is fixed to the side closer to the rotation axis than the upper end of the lower repulsive force. When the upper end of the damper is fixed to the upper part of the main body via the fixing device, the torque acting on the fixing device is weakened, so that the deformation of the fixing device can be prevented.

Further, according to the second image forming apparatus of the present invention, even if the hooked portion of the hook is hooked halfway on the hook roller, the collar rotates and the hooked portion of the hook comes off the hook roller, thereby preventing one-sided tightening. it can.

Furthermore, when the hook is formed by forming a slope inclined downward toward the outside at the tip of the hook portion, the hook portion easily comes off from the hook roller when the hook is partially tightened. Therefore, one-sided tightening can be more reliably prevented.

Further, a projection is formed at a position above the contact surface of the hook portion where the hook comes into contact with the collar and at a position away from the contact surface by a distance longer than the outer diameter of the collar. In such a case, if the upper part of the main body is pushed down excessively, the collar abuts on the protruding portion, so that it is possible to prevent the upper main body and the lower main body from colliding.

Further, when the hook roller has an eccentric rotation axis, the alignment between the upper body and the lower body can be easily adjusted by rotating the hook roller to an appropriate position and fixing the hook roller.

Further, a lower portion of the lower portion of the main body, which is rotatably fixed to the paper feeding portion, extends in a crossing direction intersecting the recording medium conveyance path, and an upper portion of the main body in a state where the opening / closing portion is opened and pushed up. And a gap formed by the lower part of the main body and located in the vicinity of the gap on the paper feeding unit side, having one side part and another side part extending in the cross direction on the opposite side, with one side part as a rotation axis In the use mode in which the other side is rotated downward and stopped, when a rectangular manual tray on which the recording medium conveyed to the recording medium conveyance path is placed is provided, the hand is inserted into the gap. Even if the upper part of the main body is pushed down, the other side rotates downward with one side of the manual feed tray as a rotation axis, so that the hand is prevented from being caught.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external appearance of a copying machine which is an embodiment of an image forming apparatus of the present invention.

FIG. 2 is a schematic diagram showing an outline of an internal structure of the copying machine shown in FIG. 1;

FIG. 3 is a perspective view showing the copying machine with a front door opened.

FIG. 4 is a perspective view showing the copying machine in which a front door is opened and an upper part of the body of the copying machine is pushed up;

FIG. 5 is a perspective view showing a state where the user is trying to close the opening / closing unit while holding the manual feed tray by hand.

FIG. 6 is a perspective view showing a state in which a manual feed tray held by a user rotates naturally.

FIG. 7 is a front view of the copying machine schematically illustrating a fixed position of the damper.

FIG. 8 is a right side view of FIG. 7;

FIG. 9 is a schematic diagram of a copying machine in which hooks are exaggerated.

FIG. 10 is a perspective view showing a state in which hook rollers are attached to a support base.

FIG. 11 is an exploded perspective view showing a hook roller.

FIG. 12 is a schematic diagram exaggerating a one-sided tightening in a state where only one of two hooks is hooked on a hook roller.

FIG. 13 is an enlarged schematic view showing a hook portion of the hook hooked on the hook roller.

14A is a perspective view showing a part of the support base in an enlarged manner, FIG. 14B is a cross-sectional view of the hook roller and the support base,
(C) is a perspective view showing a hook roller and its mounting plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Copier 18 Manual feed tray 50, 52 Hook 50b, 52b Hook hook part 60, 62 Damper 70 Paper feed part 72 Paper discharge part 74 Opening / closing part 90, 190 Hook roller 92, 192 Hook roller shaft 94 Color 100 Upper body 200 Lower body G Center of gravity at the top of the body

Claims (8)

[Claims] A recording medium transport path for transporting the recording medium in a direction from a paper supply unit to which the recording medium is fed toward a discharge unit opposite to the paper supply unit, and intersecting the recording medium transport path. An image forming apparatus which is divided into two parts, a main body upper part and a main body lower part, by opening an opening / closing part opposite to the one end part with respect to a rotation axis formed at one end part in the cross direction. The upper end is fixed to the opening / closing portion side portion of the upper body and the lower end portion is fixed to the opening / closing portion side of the lower body. The opening / closing portion is opened by pushing up the upper body. Two dampers for maintaining the state, wherein the upper ends of the two dampers are separated from the center of gravity by distances L1 and L2 in opposite directions with respect to the center of gravity of the upper part of the main body. Fixed to Further, the relationship between a repulsive force F1 that a damper separated from the center of gravity by a distance L1 pushes the upper part of the main body and a repulsive force F2 that a damper separated from the center of gravity by a distance L2 pushes the upper part of the main body is F1: F2. = L2: an image forming apparatus that satisfies L1. 2. The two dampers are arranged such that a late repulsion force when closing the opening / closing section is stronger than an initial repulsion force when the opening / closing section is started to be closed by pushing down the upper portion of the main body. The image forming apparatus according to claim 1, wherein the repulsion is set. 3. The two dampers, wherein, of the two dampers, the upper end portion having the stronger repulsive force is closer to the rotating shaft than the upper end portion having the weaker repulsive force. The image forming apparatus according to claim 1, wherein the image forming apparatus is fixed. 4. A recording medium transport path for transporting a recording medium in a direction from a paper feeding section into which the recording medium is fed to a discharge section opposite to the paper feeding section, and intersects the recording medium transport path. An image forming apparatus is divided into two parts, an upper body and a lower body, by opening an opening / closing part opposite to the one end with respect to a rotation axis formed at one end in the cross direction. A hook which is rotatably fixed to the opening / closing portion side portion of the upper portion of the main body and has an L-shaped hooking portion formed at each lower end thereof, and which holds the opening / closing portion in a closed state; A hook roller fixed to the lower portion of the main body, on which the hook portion of the hook is hooked; and a cylindrical collar that covers an outer peripheral surface of the hook roller and is rotatable in a circumferential direction of the hook roller. Image forming apparatus. 5. The image according to claim 4, wherein the hook is formed by forming a slope inclined downward toward the outside at a tip portion of the hook portion of the hook. Forming equipment. 6. The projection, wherein the hook is located above an abutting surface of the hooking portion that abuts on the collar and is separated from the abutting surface by a distance longer than an outer diameter of the collar. The image forming apparatus according to claim 4, wherein the image forming apparatus is formed. 7. The image forming apparatus according to claim 4, wherein the hook roller has an eccentric center axis of the hook roller. 8. A side portion of the lower portion of the main body, which is rotatably fixed to the paper feeding portion side and extends in a cross direction intersecting the recording medium conveyance path, and a state in which the opening / closing portion is opened and pushed up. Of the gap formed between the main body upper part and the main body lower part, the other side part extending in the cross direction on the side opposite to the one side part, which is located near the gap on the paper feeding unit side, In a use mode in which the one side portion is rotated around the other side portion and rotated down to stop, a rectangular manual tray on which a recording medium conveyed to the recording medium conveyance path is placed. The image forming apparatus according to any one of claims 1 to 7, further comprising: