JP2002162799A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of being downsized even if multiple covers have been formed. SOLUTION: In the rotation of the rollers 54a of a paired resist roller 54, both ends of a rotating center shaft are made to be a supporting point 62 for a front cover 60 in its opening and closing. And, the both ends of a rotating center shaft in the rotation of an upper roller 58a of a paired paper ejection roller 58, is made to be a supporting point 82 for an ejection cover 80 in its opening and closing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an image forming apparatus for forming an image on a recording medium, such as a copying machine, a printer, and a facsimile.

[0002]

2. Description of the Related Art As an output device of a computer or a workstation, an electrophotographic image forming apparatus for forming an image on a recording medium using a developer or the like is known. The image forming apparatus includes a photosensitive drum on which an electrostatic latent image is formed, a developing device that supplies a developer to the formed electrostatic latent image to form a developed image, and transfers the developed image to a recording medium. Then, a transfer device for forming a transfer image (toner image) on the recording medium, a fixing device for heating the toner image to fix the toner image on the recording medium, and a pair of conveyance units for conveying the recording medium while nipping the recording medium Rollers (transport roller pairs) are provided. These components such as the photosensitive drum, the developing device, the transfer device, the fixing device, and a plurality of pairs of transport rollers are accommodated in a casing having a predetermined shape.

Incidentally, the recording medium being conveyed inside the above-mentioned housing may become jammed (jam may occur). In addition, the above-described components may be replaced. A plurality of covers are fixed to the housing so as to be openable and closable in order to remove such jams (remove jammed paper) and replace parts. These covers are usually closed and cover the interior of the housing. The cover is opened only when a jam occurs as described above or when parts are replaced.
In order to open and close the cover, a rotating fulcrum, a slide rail, and the like that serve as a fulcrum when the cover is opened and closed are formed in the housing.

In the above-described image forming apparatus, a high voltage is used for image formation. For this reason, a high voltage may be applied to each of the components described above. Therefore, in the above-described image forming apparatus, in order to prevent danger, a detection switch for detecting the opening and closing of the cover is installed in the housing, and the detection switch detects that the cover is open, and a high level is applied to each component. It is configured not to apply a voltage.

[0005] The detection switch is provided corresponding to each cover. Therefore, for example, in order to improve the operability at the time of jam clearance or component replacement, when the housing has two covers, two detection switches are also provided.

[0006]

However, when the image forming apparatus has a plurality of covers as described above, a detection switch is provided for each of the covers. in this case,
Wiring for each switch is required, and
Parts for performing signal processing for each switch are also required. Therefore, the cost of the image forming apparatus is increased by these wirings and components, and the size of the housing is increased, so that the size of the image forming apparatus is increased.

Further, when a jam occurs while the recording medium is held between the pair of conveying rollers, it is difficult to remove the recording medium. Therefore, a component for manually rotating the transport roller pair is provided, or a component for separating the transport roller pair from each other is provided. In this case as well, the cost of the image forming apparatus is increased by these components, and the size of the housing is increased to increase the size of the image forming apparatus.

Further, each of the plurality of covers requires a rotation fulcrum and a slide rail. Since the space for forming the rotation fulcrum and the slide rail is occupied in the housing, the size of the housing is increased by the space and the size of the image forming apparatus is increased.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide an image forming apparatus that can be downsized even if a plurality of covers are formed.

[0010]

According to a first aspect of the present invention, there is provided an image forming apparatus comprising: a housing having a predetermined shape;
A cover that covers and opens and closes the inside of the housing, and a pair of rollers that convey the recording medium while nipping the recording medium inside the housing; (1) A cover opening / closing fulcrum formed on a rotation center axis of one of the pair of rollers and serving as a fulcrum when the cover is opened / closed. It is characterized by having.

According to a second image forming apparatus of the present invention for achieving the above object, a housing having a predetermined shape, a cover for covering and opening and closing the inside of the housing, A pair of rollers for transporting the recording medium while nipping the recording medium, and (2) the pair of rollers transporting the recording medium to form an image on the recording medium transported by the pair of rollers inside the housing. A guide member that is attached to the cover and guides the recording medium in a predetermined direction and opens and closes together with the cover; and (3) the guide member is formed on a rotation center axis of one of the pair of rollers. A guide opening / closing fulcrum, which serves as a fulcrum when the guide member opens and closes, is provided.

Here, (4) the guide member may be formed integrally with the cover. further,
(5) The pair of rollers may be paper discharge rollers for discharging a recording medium from the housing.

(6) The pair of rollers may be
It may be a registration roller that starts conveying the recording medium at a predetermined timing.

Furthermore, (7) the guide member may be provided with a separating means for separating the pair of rollers from each other when the cover is opened.

Further, (8) the cover may be provided with a separating means for separating the pair of rollers from each other when the cover is opened.

Further, the separating means may be (9) a cam attached to the cover or the guide member.

Further, (10) the image forming apparatus further includes a rotation drive transmission unit attached to the cover or the guide member for transmitting a rotation driving force for rotating the pair of rollers to the pair of rollers, (11) The rotational drive transmitting means may not transmit the rotational drive force to the pair of rollers when the cover is opened.

The image forming apparatus may further include (12) a switch for stopping power supply to a predetermined component when the cover is opened, and (13) a switch operating member for turning on and off the switch. .

Further, (14) the switch operating member may include an elastic member which is elastically deformed in contact with the switch.

(15) The cover includes a plurality of covers, and (16) the switch stops power supply to the predetermined component when any one of the plurality of covers is opened. (17) The image forming apparatus may include an opening / closing prohibiting member that does not open the other cover when the one cover is closed.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] A first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic view showing a laser printer as an example of the image forming apparatus of the present invention. FIG. 2 shows FIG.
FIG. 4 is an enlarged schematic view showing the vicinity of a boundary between a front cover and a paper discharge cover of the laser printer of FIG. FIG. 3 is a schematic diagram showing the laser printer with the front cover and the paper ejection cover opened.

As shown in FIGS. 1 and 3, a laser printer (hereinafter, referred to as a printer) 10 includes a housing 12 in which various components described later are accommodated. A paper cassette 16 on which a plurality of recording papers 14 (one example of a recording medium) are stacked is detachably mounted on a lower portion of the housing 12. Slightly above the paper feed cassette 16, an electrical unit 18 made of electronic components such as a controller is arranged. A developing device 20 for developing an electrostatic latent image with toner is disposed adjacent to the electrical component 18.

A photosensitive drum 22 on which an electrostatic latent image is formed is disposed on the side opposite to the electrical unit 18 with the developing unit 20 interposed therebetween. Above the developing unit 20, an optical unit 24 for irradiating the photosensitive drum 22 with light carrying image information is arranged.

Further, above the photosensitive drum 22, a fixing unit 30 for fixing the developed image on the recording paper is arranged. The fixing unit 30 incorporates a fixing roller 32 and a pressure roller 34 (which is an example of a pair of rollers according to the present invention) that convey the recording paper 14 while nipping it.

The photosensitive drum 22 rotates in the direction of arrow A to form an electrostatic latent image. This photosensitive drum 22
A charging roller 42 for uniformly charging the photosensitive drum 22 and a developing roller 44 for supplying the developer to the photosensitive drum 22 while rotating are arranged along the outer peripheral surface of the photosensitive drum 22. On the downstream side of the developing roller 44 in the direction of arrow A, the developed image is
4, a transfer roller 46 for transferring the image onto the photosensitive drum 22 after the transfer.
A cleaning member 48 for removing the residual toner is disposed.

In the image forming operation (printing operation) in which the printer 10 forms an image on recording paper such as recording paper, a print command is transmitted from an external computer to the printer 10 via an interface cable (not shown). Is started by When this print command is transmitted to the printer 10, a main motor (not shown) built in the printer 10 starts to rotate, the paper feed roller 50 rotates, and the recording paper 14 loaded on the paper feed cassette 16 becomes one. Paper is fed in the direction of arrow B one by one.

At the time of this paper feeding, a plurality of recording papers 14 are separated one by one by the separation pad 52, and a plurality of recording papers 1
Double feed in which 4 is simultaneously conveyed is prevented. In this way, the recording paper 14 is transported one by one to the stopped registration rollers 54 (an example of a pair of rollers according to the present invention), and the leading end of the transported recording paper 14 is
, A loop of the recording paper 14 is formed. When this loop is formed, the leading edge of the recording paper abuts against the nip portion of the registration roller 54 and is aligned, so that the skew of the recording paper is corrected.

After the loop of the recording paper 14 is formed between the paper feed roller 50 and the registration roller 54 in this manner,
At a predetermined timing, a clutch (not shown) for driving the registration roller 54 is turned on, and the registration roller 54 starts rotating. By this rotation, the developed image is transferred to the transfer roller 4.
6, the recording paper 14 is conveyed to the transfer roller 46, and the transfer roller 46
The upper developed image is transferred to the recording paper 14 to form a transfer image. The recording paper 14 on which the transfer image is formed is conveyed upward in a substantially vertical direction (vertical feed), and reaches the fixing unit 30.

On the other hand, in the printer 10, an operation of forming an electrostatic latent image on the photosensitive drum 22 is also performed in parallel with the conveyance of the recording paper as described above. In this operation, first, image information is transmitted from the external computer to the optical unit 24 via the interface cable. Optical unit 2
In step 4, the photosensitive drum 22 is exposed to laser light based on the transmitted image information. By this exposure, an electrostatic latent image is formed on the photosensitive drum 22.

When the electrostatic latent image formed on the photosensitive drum 22 reaches a position facing the developing roller 44, developer is supplied from the developing roller 44 to the electrostatic latent image, and
To form a developed image. The registration roller 54 starts rotating before the developed image reaches the transfer roller 46 with the rotation of the photosensitive drum 22, and the recording paper 14 is transferred to the transfer roller 46 so that the timing coincides with the timing at which the developed image reaches the transfer roller 46. It is transported to 46. As a result, the developed image is transferred to the recording paper 14 to form a transfer image (toner image).

The recording paper 14 on which the transfer image has been formed is conveyed to the fixing unit 30. In the fixing unit 30, the transfer image is fixed on the recording paper 14 by heating while pressing and pressing the recording paper 14 between the fixing roller 32 and the pressing roller 34. The recording paper 14 on which the transfer image is fixed in this way is guided by the paper ejection guide 56 and reaches the paper ejection roller 58, and the paper ejection roller 58 ejects the recording paper 14 out of the apparatus.

The side wall of the housing 12 near the photosensitive drum 22 is a front cover 60 (an example of a cover according to the present invention) which can be opened and closed. When the front cover 60 is closed, the inside of the housing 12 is covered and hidden. On the other hand, when the front cover 60 is opened, as shown in FIG. 3, a hand is inserted into the inside of the housing 12 so that a jam clearance or a component replacement can be easily performed.

The front cover 60 includes a pair of registration rollers 5.
4 is rotatably fixed to one of the rollers 54a. Both ends in the longitudinal direction of the rotation center axis of the roller 54a (including both ends of the rotation center axis and portions near both ends of the rotation center axis) are supported by fulcrums 62 (when the front cover 60 is opened and closed) according to the present invention. This is an example of the cover opening / closing fulcrum.)
Becomes Therefore, the rotation center axis of the roller 54a also serves as the rotation center axis of the front cover 60, and the front cover 6
There is no need to separately provide a zero rotation axis or a rotation fulcrum. For this reason, a space for newly forming the rotation axis and the rotation fulcrum of the front cover 60 is unnecessary inside the housing 12, so that the housing 12 can be reduced in size by this space and the printer 10 can be reduced in size. The transfer roller 46 is attached to the front cover 60.
Are also rotatably fixed.

The upper wall (including a part of the side wall) above the fixing unit 30 among the walls of the housing 12 is an openable and closable discharge cover 80 (an example of a cover according to the present invention). When the discharge cover 80 is closed, the inside of the housing 12 is covered and concealed. On the other hand, when the paper discharge cover 80 is opened, as shown in FIG. 3, the user can easily insert a hand into the housing 12 to perform jam clearance or component replacement.

The paper discharge cover 80 includes a pair of paper discharge rollers 58.
Are rotatably fixed to the upper roller 58a. Both ends of the rotation center axis of the roller 58a in the longitudinal direction (including both ends of the rotation center axis and portions near both ends of the rotation center axis) are supported by fulcrums 82 when the discharge cover 80 is opened and closed (the present invention). This is an example of the cover opening / closing fulcrum described above. Therefore, the rotation center axis of the roller 58a also serves as the rotation center axis of the paper ejection cover 80, and there is no need to separately provide the rotation axis and the rotation fulcrum of the paper ejection cover 80. For this reason, a space for newly forming the rotation axis and the rotation fulcrum of the paper discharge cover 80 is unnecessary inside the housing 12,
The space can reduce the size of the housing 12 and the size of the printer 10.

When opening the front cover 60, the fulcrum 6
2 with the front cover 60 in the direction of arrow C (in FIG. 3,
Clockwise). On the other hand, when the discharge cover 80 is opened, the discharge cover 80
Direction (counterclockwise in FIG. 3). As described above, when the front cover 60 and the paper discharge cover 80 are opened, they are rotated in opposite directions to each other, so that a large opening is formed in the housing 12. Therefore, jam clearance and component replacement can be performed more easily.

Here, an interlock switch 90 (an example of a switch according to the present invention) for stopping power supply to predetermined components of the printer 10 will be described.

The interlock switch 90 is for stopping power supply to the fixing unit 30 and the transfer roller 46 (an example of a predetermined component in the present invention). A high voltage is applied (supplied) to the fixing unit 30 and the transfer roller 46 from a high voltage power supply (not shown). This high-voltage power supply is controlled by a controller (not shown) of the electrical unit 18. This controller controls the high-voltage power supply based on the on / off signal transmitted from the interlock switch 90. Interlock switch 9
When 0 is on, a high voltage is applied to the fixing unit 30 and the transfer roller 46 from a high voltage power supply. On the other hand, when the interlock switch 90 is off, no high voltage is applied to the fixing unit 30 or the transfer roller 46.

The interlock switch 90 is fixed to the frame of the fixing unit 30. As shown in FIG. 2, the interlock switch 90 includes a main body 92 having a function of transmitting an on / off signal to the controller, and a switch for turning on the interlock switch 90 when pressed from outside. The terminal 94 includes an L-shaped switch lever 96 having one end fixed to the main body 92 and the other end (free end) in contact with the tip of the switch terminal 94. When the switch lever 96 is pressed by another component, which will be described later, the switch terminal 94 enters the main body 92 and the interlock switch 90 is turned on.

Inside a portion of the paper ejection cover 80 adjacent to the front cover 60, a long and thin plate-like switch operation lever 84 (which is an example of a switch operation member according to the present invention) for pressing the switch lever 96 is provided. Installed.
The upper end of the switch operating lever 84 is a rotating shaft 84a, and the switch operating lever 84 is fixed to the paper discharge cover 80 so as to freely rotate about the rotating shaft 84a. Therefore, the switch operating lever 84 is hooked to a position slightly away from the inner side surface of the paper discharge cover 80. At the lower end of the switch operation lever 84,
An elongated leaf spring 86 extending downward (which is an example of an elastic member according to the present invention) is fixed. The lower end portion 86a of the leaf spring 86 is cut and raised to form a substantially U-shape and the inner side (the casing 12).
Inside).

On the inner surface of the upper end of the front cover 60, a projection 64 is formed which protrudes inward. An inclined surface is formed at the tip of the projection 64. On the other hand, a projection 88 slightly projecting outward is formed at the lower end of the switch operation lever 84 described above. An inclined surface is also formed at the tip of the projection 88.

When both the front cover 60 and the discharge cover 80 are completely closed, the projection 64 pushes the projection 88 inward, the switch operating lever 84 rotates inward, and the lower end portion 86a of the leaf spring 86 moves to the switch lever 96. Abut and push it inward. As a result, the switch terminal 94 enters the main body 92, and the interlock switch 90 is turned on.
When one of the front cover 60 and the paper discharge cover 80 is not completely closed, the leaf spring 86
Since the lower end portion 86a cannot push the switch lever 96 inward, the interlock switch 90 remains off.

Next, the operation of the laser printer 10 for forming an image will be described.

As described above, the front cover 60 and the paper discharge cover 80 of the laser printer 10 are configured so that they can be opened and closed in directions opposite to each other (the directions of arrows C and D). When the front cover 60 or the discharge cover 80 is opened, the interlock switch 90 is turned off, and no high voltage is applied to the fixing unit 30 and the transfer roller 46, so that the laser printer 10 cannot form an image.

Therefore, in order to form an image with the laser printer 10, as shown in FIGS.
And the discharge cover 80 are completely closed, and the lower end 8 of the leaf spring 86 is closed.
6a is brought into contact with the switch lever 96 to push it inward. As a result, the switch terminal 94 enters the main body 92, the interlock switch 90 is turned on, and a high voltage is applied to the fixing unit 30 and the transfer roller 46.

In such a state, the laser printer 10
Then, as described above, an image is formed on the recording paper. By the way, during the image formation, the recording paper 14 is transported along the transport path indicated by the two-dot chain line B. During this conveyance, the recording paper 14 may be jammed and a jam may occur. Also, various parts such as the developing device 20 may be replaced.

When a jam occurs, the front cover 60 or the paper discharge cover 80 is opened to remove the jammed paper (clogged recording paper). When the front cover 60 is opened, the projection 64 pressing the projection 88 of the switch operation lever 84 separates from the projection 88. Thereby, the switch operation lever 84
Pivots slightly outward, and the lower end portion 86a of the leaf spring 86 separates from the switch lever 96. As a result, the switch terminal 9
4 slightly jumps out of the main body 92, and the interlock switch 90 is turned off.

When the interlock switch 90 is turned off, no high voltage is applied to the fixing unit 30 or the transfer roller 46. Therefore, it is safe to insert the hand into the laser printer 10 to remove the jammed paper.

When replacing various parts such as the developing unit 20, it is desirable to form a sufficiently wide opening for taking in and out of the parts. For this purpose, not only the front cover 60 but also the discharge cover 80 are opened. As a result, a sufficiently wide opening is formed.

As described above, the front cover 60 and the discharge cover 80
When the front cover 60 is opened, as shown in FIG.
, And the discharge cover 80 rotates in the direction of arrow D. Therefore, the projection 64 of the switch operating lever 84 that has pressed the projection 88 separates from the projection 88, and the leaf spring 86 of the switch operating lever 84 separates from the switch lever 96.
As a result, the switch terminal 94 slightly protrudes from the main body 92, and the interlock switch 90 is turned off.

When the interlock switch 90 is turned off, no high voltage is applied to the fixing unit 30 or the transfer roller 46. Therefore, it is safe to replace a part by inserting a hand into the laser printer 10.

When the above-described jam processing and component replacement are completed, the front cover 60 and the paper discharge cover 80 are closed. As a result, the projection 64 pushes the projection 88 inward, the switch operating lever 84 pivots inward, and the lower end 86
a contacts the switch lever 96 and pushes it inward.
As a result, the switch terminal 94 enters the main body 92, the interlock switch 90 is turned on, a high voltage is applied to the fixing unit 30, the transfer roller 46, and the like, and the image forming state is established.

As described above, the front cover 60 and the discharge cover 8
When opening the cover 0, the covers 60 and 80 are rotated in opposite directions, so that the covers 60 and 80 are rotated.
Open widely. For this reason, it is possible to smoothly perform the jam clearance and the component replacement, thereby improving workability. Also, the front cover 6
The interlock switch 90 is turned off regardless of whether the cover 0 or the discharge cover 80 is opened, so that safety can be ensured. Further, since the opening of the front cover 60 and the discharge cover 80 can be detected by one interlock switch 90 instead of two, the cost of the laser printer 10 can be reduced by one interlock switch.

The front cover 60 and the discharge cover 80
The leaf spring 86 pressing the switch lever 96 when is closed is slightly elastically deformed. Therefore, the front cover 6
Even if the paper ejection cover 80 and the paper cover 80 slightly move or rattle, these movements and rattling are absorbed by the elasticity of the leaf spring 86. For this reason, the leaf spring 86 surely pushes the switch lever 96 irrespective of such movement and rattling, and the interlock switch 90 is turned on. As a result, the operation of the interlock switch 90 can be stabilized.

As described above, the front cover 60 is configured so that the rotation center axis of the roller 54a of the pair of registration rollers 54 is
2 and rotate. Here, one of the pair of rollers is configured to be movable in a direction substantially perpendicular to the recording paper conveyance direction, and is attached by a coil spring (not shown) so as to abut against the other roller at a predetermined pressure. It is being rushed.
One roller is driven and rotated while the other roller rotates while maintaining a constant pressure contact force. The front cover 60 includes the front cover 6
A cam 66 is formed to separate the pair of registration rollers 54 from each other when 0 is open. The cam 66 is
When the front cover 60 is closed, the registration rollers 54
However, when the front cover 60 is opened, the pair of registration rollers 5 is inserted between the registration rollers 54 against the urging force of the coil spring urging the other roller.
4 apart from each other. Therefore, when the recording paper is jammed while being sandwiched between the pair of registration rollers 54, the front cover 6
By opening 0, the pair of registration rollers 54 are separated from each other, so that the jam processing can be easily performed. Therefore, the jammed paper can be completely removed, so that the recording paper does not remain inside the housing 12.

As described above, the paper output cover 80
Rotates about the rotation center axis of the roller 58a of the pair of paper discharge rollers 58 as a fulcrum 82. Here, one of the pair of rollers is configured to be movable in a direction substantially perpendicular to the recording paper conveyance direction, and is attached by a coil spring (not shown) so as to abut against the other roller at a predetermined pressure. It is being rushed. One roller is driven and rotated while the other roller rotates while maintaining a constant pressure contact force. The output cover 80
When the discharge cover 80 is open, the pair of discharge rollers 5
8 are formed to separate the cams 8 from each other. The cam 89 does not come into contact with the paper ejection roller 58 when the paper ejection cover 80 is closed, but is inserted between the paper ejection rollers 58 when the paper ejection cover 80 is opened to urge the other roller. A pair of paper discharge rollers 5 against the urging force of the coil spring.
8 apart from each other. Therefore, when the recording paper is jammed while being sandwiched between the pair of paper ejection rollers 58, the paper ejection cover 80
By opening the pair, the pair of paper discharge rollers 58 are separated from each other, so that it is easy to perform the jam clearance. Therefore, the jammed paper can be completely removed, so that the recording paper does not remain inside the housing 12. Also, if a jam occurs while the recording medium is held between the pair of conveying rollers, a part for manually rotating the pair of conveying rollers to remove the recording medium or a part for separating the pair of conveying rollers from each other is provided. Therefore, the cost of the image forming apparatus does not increase by these components, and the size of the housing does not increase and the image forming apparatus does not increase in size.

Further, the paper discharge cover 80 has the pressure roller 3
A compression coil spring 36 for pressing the fixing roller 4 against the fixing roller 32 is fixed. The compression coil spring 36 is separated from the pressure roller 34 when the paper discharge cover 80 is open. Accordingly, when the recording paper is jammed while being sandwiched between the fixing roller 32 and the pressure roller 34, the discharge cover 80
Is opened, the pressing force of the two rollers 32 and 34 is released, so that the jam can be easily removed. Therefore, similarly to the above, the jammed paper can be completely removed, so that the recording paper does not remain inside the housing 12.

The front cover 60 is provided with a guide member 68 for guiding the recording paper 14 passing through the pair of registration rollers 54 to the fixing unit 30. A guide member 56 that guides the recording paper 14 that has passed through the fixing unit 30 to a discharge roller 58 is formed on the discharge cover 80. Therefore, the front cover 60 and the discharge cover 80
Is opened, the guide members 68 and 56 move away from the transport path B. As a result, operations such as jam clearance and replacement of parts can be performed more easily. In addition, since the guide members 68 and 56 are formed on the front cover 60 and the paper discharge cover 80, the size of the housing 12 can be reduced, and the size of the laser printer 10 can be further reduced.

In this embodiment, the rotation center axis of the roller is used as the opening / closing fulcrum of the cover. However, a guide member provided on the cover may be attached to the rotation center axis of the roller to serve as the opening / closing fulcrum of the cover. Further, the cam as the separating means may be provided on the guide member instead of the cover. [Second Embodiment] A second embodiment of the present invention will be described with reference to FIGS.

FIG. 4 is a schematic view showing a laser printer which is an example of the image forming apparatus according to the second embodiment. FIG.
FIG. 3 is a schematic diagram showing a laser printer with a front cover and a paper ejection cover opened. In these drawings, the same components as those shown in FIGS. 1 to 3 are denoted by the same reference numerals.

In the laser printer 100, the recording paper 14
Is formed above the fixing unit 30 to guide the sheet from the fixing unit 30 to the paper discharge roller 58. A discharge cover 110 is fixed to the upper surface of the transport path change guide 112. The transport path change guide 112 is opened and closed by rotating about the fulcrum 82 as a rotation center axis.

Under the transport path change guide 112, a V-shaped projection 114 (an example of an open / close prohibiting member according to the present invention) and this projection 114 are turned in the direction of arrow G (clockwise in FIG. 4). A rotation spring 116 that urges to move is disposed. When the discharge cover 110 is open, the projection 114 is rotated in the direction of arrow G by the rotation spring 116, and one side 114 a of the V-shape protrudes out of the housing 102. Even if the user tries to close a front cover 130 described later in this state, the inner surface of the front cover 130 contacts the one side 114a of the V-shape, so that the front cover 130 cannot be completely closed. When the discharge cover 110 is closed, the protrusion 114 rotates in the direction opposite to the direction of arrow G, so that the front cover 130 is completely closed. Therefore, the front cover 130 can be completely closed only when the discharge cover 110 is completely closed.

A drive transmission gear 11 for transmitting a rotational driving force to the discharge roller 58 is provided on the transport path change guide 112.
Reference numeral 8 (which is an example of the rotation drive transmission means according to the present invention) is rotatably fixed. When the discharge cover 110 is opened,
As shown in FIG. 5, the transport path change guide 112 is opened together with the discharge cover 110, and the drive transmission gear 118 is separated from the discharge roller 58. Therefore, when the discharge cover 110 is open, the discharge rollers 58 are released from the gear train and can rotate freely.

Further, the laser printer 100 has a front cover 130 which rotates about a fulcrum 62 formed on the registration roller 54a as a rotation center axis. This front cover 13
0 is similar to the front cover 60 (see FIG. 1 and the like). On the inner side surface of the front cover 130, a projection 132 for pushing the switch lever 96 of the interlock switch 90 to turn on is formed.

At the upper end of the front cover 130, an open prohibition projection 134 (which is an example of an open / close prohibition member according to the present invention) protruding inward is formed. This opening prohibition projection 134
When the paper ejection cover 110 is completely closed and the front cover 130 is completely closed, the paper ejection cover 110 fits into the recess 120 of the transport path change guide 112. Therefore, the discharge cover 110 can be opened only when the front cover 130 is opened.

When a paper jam occurs during image formation by the laser printer 100, the front cover 13 is used for paper jam processing.
0 and the paper ejection cover 110 are opened. In this case, first, the front cover 130 is opened and the projection 132 is separated from the switch lever 96. As a result, the interlock switch 90 is turned off, and a high voltage is not applied to the fixing unit 30, the transfer roller 46, and the like, so that the jam can be safely removed.

When the front cover 130 is opened, the opening prohibition projection 134 is
Get out of zero. Therefore, as described above, the discharge cover 110 can be opened only when the front cover 130 is opened. When the paper ejection cover 110 is opened, the jam is easily performed because the drive transmission gear 118 is separated from the paper ejection roller 58 as described above.

In each of the above embodiments, a laser printer has been described as an image forming apparatus. However, the present invention can be applied to a copying machine or the like which requires jam clearance or component replacement.

[0070]

As described above, in the first image forming apparatus of the present invention, since the cover opening / closing fulcrum is formed on the rotation center axis of the roller, a new space for forming this cover opening / closing fulcrum is provided. Not required in the enclosure. Therefore, the size of the housing can be reduced by this space.

In the second image forming apparatus of the present invention,
Since the guide opening / closing fulcrum is formed on the rotation center axis of the roller, no new space for forming the guide opening / closing fulcrum is required in the housing. Therefore, for this space,
The housing can be downsized.

Here, when the guide member is formed integrally with the cover, the guide member and the cover are formed integrally, so that these can be miniaturized and the housing can be further miniaturized.

Further, when the pair of rollers is a discharge roller for discharging recording paper from the housing, the space occupied by a cover (discharge cover) formed near the discharge roller can be reduced. Even if a paper ejection cover is formed, the size of the housing can be reduced.

Further, when the guide member is provided with pressing means for pressing the paper discharge rollers together when the guide member is closed, when the guide member is closed (that is, when the cover is closed). (When is closed), the discharge rollers press each other, so that the recording paper is reliably discharged by the discharge rollers.

Further, when the image forming apparatus is provided with a cam attached to the cover or the guide member for separating the pair of rollers from each other when the cover is opened, the pair of rollers is opened when the cover is opened. Since the rollers are separated from each other, the jam can be easily removed.

Further, the image forming apparatus is provided with a rotational drive transmitting means attached to the cover or the guide member for transmitting a rotational drive force for rotating the pair of rollers to the pair of rollers. Means are
In the case where the rotational driving force is not transmitted to the pair of rollers when the cover is opened, the pair of rollers rotate freely when the cover is opened, so that an image forming apparatus that can easily perform the jam processing is obtained.

Further, when the image forming apparatus includes a switch for stopping power supply to a predetermined component when the cover is opened, and a switch operating member for turning on and off the switch, the predetermined component is opened when the cover is opened. Since the power supply to the image forming apparatus is stopped, an image forming apparatus with higher safety can be obtained.

Further, when the switch actuating member has an elastic member which is elastically deformed in contact with the switch, the elastic member is elastically deformed, so that the switch is not damaged.

Further, the cover includes a plurality of covers, and the switch stops power supply to the predetermined component when any one of the plurality of covers is opened. If the image forming apparatus has an opening / closing prohibition member that does not close the other cover when one cover is open, it is possible to prevent forgetting to close the cover because one cover is open and the other cover does not close. ,
An image forming apparatus with even higher safety can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a laser printer as an example of an image forming apparatus of the present invention.

FIG. 2 is an enlarged schematic view showing the vicinity of a boundary between a front cover and a paper discharge cover of the laser printer of FIG. 1;

FIG. 3 is a schematic view showing the laser printer of FIG. 1 with a front cover and a paper ejection cover opened.

FIG. 4 is a schematic diagram illustrating a laser printer as an example of an image forming apparatus according to a second embodiment of the invention.

FIG. 5 is a schematic view showing the laser printer of FIG. 4 with a front cover and a paper ejection cover opened.

[Explanation of symbols]

 10, 100 laser printer 12, 102 housing 30 fixing unit 46 transfer roller 54 registration roller 60, 130 front cover 62, 82 fulcrum 80, 110 paper discharge cover 84 switch operating lever 86 leaf spring 90 interlock switch 118 drive transmission gear 134 Do not open protrusion

Claims (12)

[Claims] 1. A housing having a predetermined shape, a cover for covering and opening the inside of the housing, and a pair of rollers for transporting a recording medium while nipping the recording medium inside the housing. An image forming apparatus that forms an image inside the housing on a recording medium conveyed by the rollers, wherein the cover formed on the rotation center axis of one of the pair of rollers is opened and closed. An image forming apparatus, further comprising a cover opening / closing fulcrum serving as a fulcrum. 2. A housing having a predetermined shape, a cover that covers and opens and closes the inside of the housing, and a pair of rollers that convey a recording medium while holding the recording medium inside the housing. An image forming apparatus that forms an image on a recording medium conveyed by a pair of rollers inside the housing, wherein the pair of rollers guides the recording medium conveyed in a predetermined direction, is attached to the cover, and opens and closes together with the cover. An image forming apparatus comprising: a guide member; and a guide opening / closing fulcrum formed on a rotation center axis of one of the pair of rollers and serving as a fulcrum when the guide member opens and closes. . 3. The image forming apparatus according to claim 2, wherein the guide member is formed integrally with the cover. 4. The image forming apparatus according to claim 1, wherein the pair of rollers is a discharge roller that discharges a recording medium from the housing. 5. The image forming apparatus according to claim 1, wherein the pair of rollers are registration rollers that start conveying a recording medium at a predetermined timing. 6. The image forming apparatus according to claim 4, wherein the guide member is provided with a separating unit that separates the pair of rollers from each other when the cover is opened. 7. The image forming apparatus according to claim 4, wherein the cover is provided with a separation unit that separates the pair of rollers from each other when the cover is opened. 8. The image forming apparatus according to claim 6, wherein the separation unit is a cam attached to the cover or the guide member. 9. A rotating drive transmitting unit attached to the cover or the guide member for transmitting a rotational driving force for rotating the pair of rollers to the pair of rollers, wherein the rotating drive transmitting unit includes: The image forming apparatus according to any one of claims 2 to 8, wherein the rotational driving force is not transmitted to the pair of rollers when the roller is opened. 10. A switch according to claim 1, further comprising a switch for stopping power supply to a predetermined component when said cover is opened, and a switch operating member for turning on and off said switch. The image forming apparatus according to claim 1. 11. The image forming apparatus according to claim 10, wherein the switch actuating member has an elastic member that elastically deforms by contacting the switch. 12. The switch according to claim 1, wherein the cover is provided with a plurality of switches, and the switch stops power supply to the predetermined component when any one of the covers is opened. 2. An opening / closing prohibition member for preventing another cover from being opened when the cover is closed.
12. The image forming apparatus according to 0 or 11.