JPH086336A - Image forming device - Google Patents

Abstract

PURPOSE:To reduce the number of part items and secure the rigidity of a main body frame. CONSTITUTION:Upper sections of the right and left side plates 1R, 1L of a main body frame 1F are connected by the optical frame 56 of an optical unit 50. The positioning hole 56b of a left fitting section 56L is coupled with a positioning boss 1b on the left side plate 1L, and the right fitting section 56R of the optical unit 56 is properly moved in the longitudinal direction for positioning via an optical path position adjusting jig. The optical frame 56 is fixed on the main body frame 1F via fastening holes 1c, 1d, 56c, 56d after positioning. The optical unit 56 serves as a reinforcing member, prevents the deformation of the right and left side plates 1R, 1L liable to be deformed, and secures the rigidity of the main body frame 1F.

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 for forming an image on a recording medium.

[0002]

2. Description of the Related Art In electrophotographic image forming apparatuses such as copiers and laser beam printers used in offices, especially small desktop type apparatuses, further downsizing and simplification of the structure are required. .

In an electrophotographic image forming apparatus, generally, a toner image formed on a photosensitive drum (image carrier) in an image forming unit is conveyed from a paper feeding cassette along a conveying path to a recording medium (for example, paper). ), And the transferred toner image is fixed on the recording medium body by a fixing device,
Eject the recording medium onto the output tray.

Further, in a small type, the image forming portion is constituted by a process cartridge (for example, a photosensitive drum, a charger, a developing device, a cleaning device and the like are integrally incorporated in a cartridge container), and a fixing device. Is composed of a member for heating and pressurizing. Then, a paper feed cassette is installed in the lateral direction (substantially horizontal) at the bottom of the box-shaped device body, and the above-mentioned process cartridge and fixing device are arranged in the transport path formed above the paper feed cassette. A paper ejection tray is provided. That is, the apparatus main body is downsized by arranging the paper feed cassette in the lower part, the process cartridge and the fixing device in the middle part, and the paper discharge tray in the upper part so that they overlap each other. The installation area (occupied area) is being reduced.

Further, the main body frame 1F of the above-mentioned image forming apparatus, as shown in FIG. 10, has left and right side plates 1L, 1R.
The front stay 1S, which is placed under both side plates 1L, 1R.
₁ , a middle stay 1S ₂ and a rear stay 1S ₃ are connected to each other. By the way, if left as it is, the left and right side plates 1
L1R upper part lacks strength, so both side plates 1L, 1R
The upper part of is connected by a reinforcing plate 58. The optical unit 50A and the mirror unit 50B are arranged on the upper surface of the reinforcing plate 58. By doing so, the main body frame 1F is provided with sufficient rigidity, and the mounting accuracy of each component to be mounted including the optical unit 50A is secured.

[0006]

However, according to the above-described image forming apparatus, since the recording medium before image formation and the recording medium after image formation are supported substantially horizontally by the sheet feeding cassette and the sheet discharging tray, respectively, There was a limit to the reduction of the area occupied by the main body. That is, the actual occupied area of the device body, which also takes into account the occupied area by the recording medium,
There is a problem that it is difficult to make the area smaller than the largest of the recording media used.

As for the main body frame 1F, the optical unit 50A and the mirror unit 50B are mounted on the reinforcing plate 58.
However, there is a problem that the number of parts is large, such as arranging the parts, and the overall configuration is complicated and the parts mounting accuracy is deteriorated. That is, from the viewpoint of improving the assembling property of the image forming apparatus and reducing the number of parts, when considering a mechanism in which the main body frame 1F has many functions and, for example, a roller-shaped member is dropped from above to assemble, the main body frame is considered. The upper part of the recording medium conveyance path (paper path) in 1F needs to be in an open state. Therefore, the rigidity of the upper portions of the left and right side plates 1L, 1R is impaired. Therefore, if a beam-like rigidity supply member that is larger than the conventional example is attached to the upper portions of the left and right side plates, the cost is significantly increased, and one of the advantages of downsizing is lost. In addition, via the reinforcing member 58,
If the optical unit 50A is attached, an intermediate error element increases, which causes a big problem that it is difficult to secure the positional accuracy. Further, if reinforcement is performed while avoiding the optical unit 50A, there is a possibility that an opening for attaching and detaching the process cartridge cannot be provided.

Further, in order to integrally form the upper replenishing member 58 into a frame, the die slide is complicated, and the assembling operation requires two or more degrees of freedom, which is inconvenient. .

Therefore, it is an object of the present invention to provide an image forming apparatus in which the area occupied by the image forming apparatus main body is reduced and the overall structure is simplified without lowering the rigidity of the main body frame. To do.

[0010]

The main constitution of the present invention for solving the above problems is to support a recording medium for feeding in a longitudinal direction in an image forming apparatus for forming an image on the recording medium. A first supporting means, a second supporting means for supporting a recording medium after image formation in a longitudinal direction, an image carrier provided above a conveying path extending from the first supporting means to the second supporting means, An information light emitting means for providing information light according to image information to the image carrier, the information light emitting means being provided between the first support means and the second support means and above the image carrier. A transfer unit provided below the transport path for transferring the toner image formed on the image carrier to a recording medium, and a fixing unit for fixing the toner image transferred to the recording medium to the recording medium. , The left and right side plates and the connecting portion that connects these left and right side plates Characterized in that it comprises a body frame, and a optical frame that houses the information light emitting means while connecting an upper portion of the left and right side plates with and.

Further, a feeding position for feeding the recording medium supported by the first supporting means, a transfer position by the transfer means, and a fixing position, which are sequentially arranged from the upstream side to the downstream side of the transport path. The fixing positions by the means may be arranged at lower positions in this order.

[0012]

Based on the above structure, the first supporting means and the second supporting means vertically support the recording medium to be fed (before image formation) and the recording medium after image formation before image formation, respectively. Therefore, the occupied area of the image forming apparatus main body is not directly affected by the length of the recording medium as the image forming target in the transport direction. That is, by making the horizontal length of the conveying path connecting both supporting means shorter than the length of the recording medium in the conveying direction, it is possible to make the area occupied by the image forming apparatus main body smaller than the area of the recording medium. Becomes Further, by forming the optical unit that connects the upper portions of the left and right side plates of the main body frame with, for example, a strength member, the main body frame can have sufficient rigidity without increasing the number of parts.

Further, by setting the transfer position lower than the feeding position for the recording medium and setting the fixing position lower than the transfer position, the recording medium conveyed in the conveying path is conveyed without countering gravity. As a result, the posture of the tip is stable and the sheet is conveyed smoothly.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 shows a schematic configuration of a laser beam printer M using a process cartridge as an example of an image forming apparatus according to the present invention. As the recording medium P on which an image is to be formed, in addition to ordinary plain paper (copy paper), special paper such as thick paper and envelope, and sheet material other than paper such as OHP film may be used. However, in this embodiment, the case of using ordinary plain paper will be described.

First, an outline of the configuration of a laser beam printer (hereinafter simply referred to as "printer") M shown in the figure will be described.

The printer M is referred to as a printer body 1 (hereinafter simply referred to as "body 1". In the printer body, a "body frame 1F" is used when referring to a framework.
Let's say. ) At the rear part thereof, a first supporting means 10 for supporting the recording medium P before image formation is provided in the vertical direction,
At the front part of the main body 1, a second supporting means 20 for supporting the recording medium P after image formation in the vertical direction is provided. And these first
The lower end portion 10a of the supporting means 10 and the lower end portion 20a of the second supporting means 20 are connected by a conveying path 30 extending from the rear portion to the front portion of the main body 1, and as a whole, a U-shaped path (hereinafter,
It is called "vertical U-shaped pass". ) Is composed. Printer M
Is a process cartridge 40 in which a drum-shaped electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 41 and the like which is disposed immediately above the transport path 30 is integrally incorporated, and above the process cartridge 40. The information light emitting means 50 provided and the photosensitive drum 4 below the intermediate portion of the transport path 30.
1, and a fixing unit 70 disposed downstream of the transport path 30 and immediately below the lower end of the second supporting unit 20. Based on the above-mentioned vertical U-shaped path, the process cartridge 40 and the information light emitting means 50 are arranged inside thereof, the transfer means 60 is arranged outside thereof, and the fixing means 70 is arranged so as to straddle the conveyance path 30 on the downstream side. Will be arranged respectively.

The operation of the printer M having the above configuration will be briefly described. First, a toner image is formed on the photosensitive drum 41 by the information light emitting means 50 and the like. On the other hand, the recording medium P is fed downward from the first supporting means 10 to convey the recording path 30.
Is supplied to the photosensitive drum 41 via the upstream side of the above, and the above-mentioned toner image on the photosensitive drum 41 is transferred to the supplied recording medium P by the transfer means 60. The recording medium P to which the toner image is transferred is fixed to the surface of the recording medium P by the fixing unit 70, then discharged upward, and supported by the second supporting unit 20 in the vertical direction.

The printer M having the above structure and operation,
That is, in the printer M having the vertical U-shaped path, the occupied area of the main body 1 can be reduced by shortening the length of the transport path 30 in the front-rear direction, regardless of the length of the recording medium P in the transport direction. Is.

The structure of each member will be described below in order from the first supporting means 10.

The first supporting means 10 is provided at the rear portion of the main body 1 and has an abutting portion 11, a leading end supporting portion 12, and a paper feed tray 13 in this order from below. The abutting portion 11 supports the front end of the recording medium P before image formation from below and supports the weight of the recording medium P. The tip support portion 12 is swingably supported in the front-rear direction by the main body 1 around the shaft 12a, and is urged forward by a spring 12b arranged on the back surface of the lower end portion. The front end support portion 12 biased forward is retracted rearward by a cam member (not shown) before feeding, and the above-mentioned cam member rotates to attach the recording medium P forward only during paper feeding. Energize. The highest recording medium P among the recording media P before feeding is fed by the abutting portion 11 and the separating claws to the feeding position A.
It is positioned at 1 and waits for feeding. When the recording medium P is fed, the next recording medium P is arranged at the feeding position A1 by the tip support portion 12 biased by the spring 12b. The paper feed tray 13 is arranged so as to vertically project from the rear end of the upper surface of the main body 1. The paper feed tray 13 supports the middle portion and the rear end portion of the recording medium P from the back side (rear surface side) of the recording medium P, and supports the entire recording medium P before image formation in a vertical plane. On the front side of the paper feed tray 13, two movable regulating plates 13L and 13R that regulate the position of the recording medium P in the left-right direction (refers to the left and right when viewed from the front side to the rear side), and the manual feed. A manual feed guide 13a for guiding the recording medium P at the time is arranged. In addition, at the upper end of the paper feed tray 13, extending upward,
An extension guide 13b that stably supports the recording medium P having a long length in the transport direction is arranged so that it can move in and out. The paper feed tray 13 is detachably attached to the upper surface of the main body 1. Here, the first supporting angle θ ₁ of the recording medium P before image formation, that is, the abutting portion 11 and the leading end supporting portion 1 described above.
2. The first support angle θ ₁ which is the angle formed by the recording medium P in the state of being supported in a plane by the first supporting means 10 configured by the feeding tray 13 and the like is 60 ° to 90.
By setting the angle to 0, it is possible to contribute to the reduction of the occupied area of the main body 1, and it is also possible to realize good feeding of the recording medium P that effectively utilizes gravity. The first support angle θ ₁ is preferably set to 70 ° to 75 °.

The second supporting means 20 has the above-mentioned first supporting means 10 provided at the rear portion of the main body 1, while the main body 1 has the following structure.
It is provided in the front part of the. The second supporting means 20 is the main body 1
Is provided on the openable / closable exterior cover 2 (the double-dotted line in the figure indicates the exterior cover 2 in the middle of the opening / closing operation), and the abutting portion 21 and the paper discharge order from the bottom. It has a tray 22 and an extension tray 23. With respect to the recording medium P on which an image has been formed, the abutting portion 21 supports the rear end from below, the paper ejection tray 22 supports the latter half of the rear side, and the extension tray 23 supports the front half of the rear side. . Extension tray 2
3 is supported by a paper discharge tray 22 so as to be able to move up and down, and is extended tray 23 above the main body 1.
And the discharge tray 22 support the recording medium P on which an image has been formed in a plane shape in the vertical direction. The angle with respect to the horizontal plane of the recording medium P in the state of being supported in the vertical direction is defined as the second
Assuming that the support angle is θ ₂ , the second support angle θ ₂ is 55
Set to ° to 75 °. Note that this second support angle θ ₂
Is preferably set to 65 ° to 70 °. The opening / closing operation of the exterior cover 2 having the paper discharge tray 22 and the like will be described later together with the attaching / detaching operation of the process cartridge 40.

The transport path 30 connects the lower end portion 10a of the first supporting means 10 and the lower end portion 20a of the second supporting means 20,
A path for transporting the recording medium P extending from the rear part to the front part of the main body 1 is configured. The transport path 30 is separated from the rear portion (upstream side) to the front portion (downstream side) in order.
1, pre-transfer guides 32a and 32b, post-transfer guide 33
a, 33b, and the reverse guide 34 on the downstream side of the fixing unit 70. Also, diagonally above the separation pad 31,
A paper feed roller 35 is arranged, and a conveyance roller 36 is arranged below the paper feed roller 35. Paper feed roller 35
Has an outer peripheral surface eccentrically formed with respect to the shaft 35a, and is rotated in the direction of arrow R35 so that the first support means 10
The uppermost recording medium P is fed from the above to prevent the double feeding of the recording medium P between the separation roller 31 and the conveyance roller 36.
Together with this, the recording medium P is configured to be conveyed. The pre-transfer guide 32a on the upstream side is configured to move gently downward, and the pre-transfer guide 32b on the downstream side is configured to be substantially horizontal, and the lower surface 4 of the upper process cartridge 40 is formed.
0a to guide the recording medium P to the photosensitive drum 41
And the transfer roller 61 of the transfer unit 60. The post-transfer guide 33a is formed on the inclined surface which is inclined downward to the front, and the post-transfer guide 3 which is continuous with this is formed.
3b has a gentle concave surface. The recording medium P after the toner image transfer is guided to the fixing position A3 formed between the fixing film of the fixing unit 70 and the pressure roller (both will be described later) by the post-transfer guides 33a and 33b. In addition, on the most upstream side of the post-transfer guide 33a, a charge removing member 33c that removes excess charges of the recording medium P after the toner image transfer is attached. The reversing guide 34 is a gently curved guide provided between the conveying roller 37 on the downstream side of the fixing unit 70 and the paper discharge roller 38 above the fixing roller 70, and guides the recording medium P after fixing the toner image upward. Guide toward the second support means 20. In addition, this inversion guide 34
Is integrally formed with the exterior cover 2 described above.

As described above, the feeding path A1, the transfer position A2, and the fixing position A are arranged in this order on the conveying path 30 from the upstream side.
3 are provided, but these positions A1, A2, A3
Are set to be sequentially arranged in this order at lower positions. Therefore, at the time of image formation, these positions A1,
The recording medium P that sequentially passes through A2 and A3 is at a high place (A1).
Therefore, the sheets are sequentially conveyed to a low place (A3), and smooth conveyance is performed according to gravity. Furthermore, since the leading end of the recording medium P at this time is supported from below by the pre-transfer guides 32a, 32b and the post-transfer guides 33a, 33b, these guides 32a, 32b, 33a, 33 are provided.
Following b, the paper is conveyed in a stable posture. For this reason, it is surely introduced into the transfer position A2 and the fixing position A3, and the conveyance failure such as paper jam is well prevented.

In the process cartridge 40, a photosensitive drum 41, a charging roller (charging means) 42, a developing device (developing means) 43, and a cleaning device (cleaning means) 44 are integrated into a cartridge container 45 to form a cartridge. It is detachable from the main body 1. The photosensitive drum 41 is a drum-shaped electrophotographic photosensitive member as described above, and includes a motor 84 (described later) on the main body 1 side.
Is driven to rotate in the direction of arrow R41. The charging roller 42 is disposed in contact with the surface of the photosensitive drum 41, and is driven to rotate as the photosensitive drum 41 rotates in the direction of arrow R41. A charging voltage in which a DC voltage and an AC voltage are superposed is applied to the charging roller 42 by the high voltage generating unit 83 on the substrate 80 on the main body 1 side, and the rotation of the photosensitive drum 41 causes the surface of the photosensitive drum 41 to move. It is uniformly charged. The developing device 43 has a toner container 43a for containing toner and a developing sleeve 43b. The developing sleeve 43b has a magnet inside and carries toner on the surface by rotating. The layer thickness of the toner on the surface is regulated by the regulation blade 43c and an electric charge is applied to the toner, and the toner is attached to the electrostatic latent image formed on the photosensitive drum 41 by the information light emitting means 50 described later.
Form a toner image. In the process cartridge 40 according to the present embodiment, the developing device 43 can arrange the toner container 43a on the upper side and the developing sleeve 43b on the lower side. Therefore, the toner in the toner container 43a naturally develops due to gravity. It drops toward the sleeve 43b. Therefore, it is not necessary to attach a special mechanism for conveying the toner in the toner container 43a toward the developing sleeve 43b, such as a stirring member. As a result, the structure of the process cartridge 40 can be simplified. The cleaning device 44 includes a cleaning blade 44a that rubs the surface of the photosensitive drum 41 after the toner image transfer to remove residual toner on the surface, and a cleaning container 44b that collects the removed waste toner. A through hole 45a for exposure is formed in the upper portion of the cartridge container 45. The operation of attaching / detaching the process cartridge 40 to / from the main body 1 will be described later.

The information light emitting means 50 irradiates the surface of the photosensitive drum 41 with light through the above-mentioned through hole 45a for exposure, and is arranged above the process cartridge 40 as a whole. The information light emitting means 50 includes a semiconductor laser 55 that oscillates a laser beam based on an image signal, and a polygon mirror 51 that reflects the laser beam while rotating it.
And a motor 52 for rotating the polygon mirror 51,
The lens 53 and the reflection mirror 54 are provided. The information light emitting means 50 includes a polygon mirror 51 and a first supporting means 1.
The reflecting mirror 54 is disposed on the 0 side (rear side) and downward, and on the second supporting means 20 side (front side) and upward. In other words, the whole is arranged in the front upward direction, contrary to the above-mentioned transport path 30. By arranging in this way, it is possible to prevent the height of the main body 1 from becoming high, and in a compact configuration, the required optical path length of the laser beam from the polygon mirror 51 to the photosensitive drum 41 via the reflection mirror 54 is reduced. It is possible to secure the position and to set the mounting position of the manual insertion guide 13a of the first supporting means 10 to a position where operability is good. By the irradiation of this laser beam, the photosensitive drum 41
An electrostatic latent image corresponding to the image signal is formed on the top. Each member forming the information light emitting means 50 is integrally incorporated in an optical frame described later, and is unitized as a whole.

The process cartridge 40 and the information light emitting means 50 described above are arranged between the rear first supporting means 10, the front second supporting means 20, and the lower conveying path 30, that is, a vertical U-shaped path. It is compactly placed in the inner space.

The transfer means 60 includes a transfer roller 61, which is in contact with the photosensitive drum 41 from below, below the conveying path 30.
And a transfer position A2 is formed between the photosensitive drum 41 and the photosensitive drum 41. The left and right ends of the cored bar 61a of the transfer roller 61 are respectively held by bearings 63 urged by springs 62, so that the transfer roller 61 is brought into contact with the surface of the photosensitive drum 41 with a predetermined pressing force. A transfer voltage having a polarity opposite to that of the toner image on the photosensitive drum 41 is applied to the transfer roller 61 by the high-voltage generating unit 83 on the substrate 80.
The toner image on the photosensitive drum 41 is transferred onto the surface of the recording medium P passing through the transfer position A2.

The fixing means 70 includes a ceramic heater 72 held by a main body 1 via a spring 71, a fixing film 74 endlessly mounted on the outer periphery of a guide 73, and a fixing film 74 which is in contact with the fixing film 74 from below and is fixed. It has a pressure roller 75 that forms a fixing position A3 with the film 74. Since the ceramic heater 72 and the fixing film 74 have small heat capacities, it takes a short time to heat up to a predetermined temperature required for fixing after energization. This prevents unnecessary heat from being radiated from the fixing means 70. The fixing unit 70 melts and fixes the toner image when the recording medium P having the toner image transferred on the surface at the upstream transfer position A2 passes the transfer position A3 while carrying the unfixed toner image. And is fixed on the surface of the recording medium P.

The lower part of the main body 1, that is, the above-mentioned transport path 30.
A substrate 80 is disposed below the substrate. A control unit 81, an AC input unit 82, a high voltage generation unit 83, and a motor 84 are arranged on the substrate 80 in this order from the downstream side (front side).
The heights of these are gradually increasing in this order.
That is, among the members on the substrate 80, tall members are arranged at the rear part and short members are arranged at the front part. This is consistent with the configuration of the transport path 30 described above, where the rear side is high and the front side is low. That is, the arrangement of each member on the substrate 80 is determined according to the space below the transport path 30. This contributes to downsizing of the main body 1.

Next, the opening / closing operation of the outer cover 2 of the main body 1 and the mounting operation of the process cartridge 40 will be described with reference to FIG.

While covering the front surface of the main body 1, the above-mentioned second
The outer cover 2 that also serves as the supporting means 20 is supported by the main body 1 so as to be swingable in the direction of arrow R2 around the lower hinge 2a. When the exterior cover 2 is opened as shown in the figure, a large opening 1a is exposed on the front surface of the main body 1. The process cartridge 40 is mounted inside the main body 1 through the opening 1a. At this time, the conveyance path 30 in the lower part of the space where the process cartridge 40 is mounted.
Is composed in a downward direction. On the other hand, since the information light emitting means 50 above the space is arranged on the upper side in the opposite direction to the transport path 30, the opening 1a is opened large, and the mounting operation of the process cartridge 40 is extremely easy. Will be things. The process cartridge 40 mounted in the main body 1 can be easily removed in the same manner. Further, when the process cartridge 40 is removed, the transport path 3
A portion of 0 from the feeding position A1 to the fixing position A3 is exposed, and jam processing of the recording medium P and the like can be easily performed.

Next, referring to FIG. 1, the image forming operation of the entire printer M having the above configuration will be briefly described.

First, the recording medium P is set on the first supporting means 10 in the vertical direction. The photosensitive drum 41 in the process cartridge 40 is rotationally driven, and by the charging roller 42,
The surface of the photosensitive drum 41 is uniformly charged with, for example, a negative polarity.
The information light emitting means 50 exposes the uniformly charged surface of the photosensitive drum 41. Laser light based on an image signal is emitted from the information light emitting means 50 to irradiate the surface of the photosensitive drum 41. Negative charges are removed from the light-irradiated portion on the photosensitive drum 41 to form an electrostatic latent image. This electrostatic latent image becomes a toner image by so-called reversal development in which toner of negative polarity is attached by the developing device 43.
On the other hand, the recording medium P, which has waited with its leading end aligned with the sheet feeding position A1, is supplied to the transfer position A2 by the sheet feeding roller 35 so as to match the timing with the toner image on the photosensitive drum 41. At the transfer position A2, by the transfer roller 61 to which a transfer voltage having a positive polarity opposite to that of the toner is applied,
The toner image on the photosensitive drum 41 is transferred onto the recording medium P. In the fixing means 70, the unfixed toner image on the surface of the recording medium P is fixed by being heated and pressed. The recording medium P on which the toner image has been fixed is vertically ejected onto the second supporting unit 20 by the paper ejection roller 38 via the reversing path 34.

In the printer M of this embodiment, the recording medium P before the image formation and the recording medium P after the image formation are respectively supported by the first supporting means 10,
The occupied area of the main body 1 is reduced by vertically supporting the second support means 20 and shortening the transport path 30.

In the printer M having the above-mentioned structure, the unitized information light emitting means 5 disposed on the upper portion of the main body 1.
0 (hereinafter referred to as "optical unit 50") is used as a strength member. This will be described below. It should be noted that each of the drawings shown below is a simplified illustration of the basic configuration of the printer M shown in FIGS. 1 and 2, and therefore the reference numerals for the details are omitted. However, as for the fixing means 70, in FIG.
4 and the like are used, the fixing roller 76 is used instead of this in FIGS. In addition, this fixing roller 7
6, pressure roller 75, conveyance roller 37, reversing guide 3
4, and the discharge roller 38 is integrated as a unit (hereinafter referred to as "fixing unit 70").

The method of assembling the printer M will be described with reference to the assembly diagram of FIG.
A brief description will be given with reference to the exploded view of FIG. 4 and the exploded perspective view of FIG. As shown in FIG. 5, the body frame 1F has a left side plate 1L and a right side plate 1R, which are attached to the front stay 1S.
₁ , a middle stay 1S ₂ , a rear stay 1S _{3 and the} like, which are connected to each other. An opening is formed above the main body frame 1F, and the optical unit 50 is fixed to the opening by connecting the upper surfaces of the left and right side plates 1L, 1R. The positioning and the like at this time will be described later. Subsequently, as shown in FIGS. 3 and 4, the paper feed roller 35 and the transfer roller 61 are fitted from above, and the transport roller 36 is fitted from below at one operation.

Next, the fixing unit 70 is fixed from the front and the substrate 80 is fixed from the lower side. Furthermore, body frame 1
The second support means 20 and the first support means 20 are provided on the front and rear portions of F, respectively.
Attach the support means 10. Finally, the second supporting means 20
With the process cartridge 40 open inside the main body frame 1F along the chain double-dashed line m in the figure.
Attach.

Next, the above-mentioned optical unit 50 will be described in detail. The optical unit 50 includes a box-shaped optical frame 56.
A semiconductor laser 55, a polygon mirror 51, a motor 5
2, the lens 53, and the reflection mirror 54 are integrally incorporated. As shown in FIG. 5, mounting portions 56L and 56R are provided on the left and right of the optical unit 50, and the mounting portions 56L and 56R are provided with positioning holes 5 for positioning the optical frame 50 with respect to the main body frame 1F.
6b, fastening holes 56c and 56d for fixing the same,
56e and 56f are provided. On the other hand, on the upper surfaces of the left and right side plates 1L, 1R of the main body frame 1F, the positioning boss 1b, the fastening holes 1c, 1d, 1 are provided at positions corresponding to these.
e and 1f are drilled.

As shown in FIG. 5, the positioning hole 56b on the optical unit 50 side is formed in the positioning boss 1 on the body frame 1F side.
The optical unit 50 is fitted in the position b, and the position of the left end side of the optical unit 50 in the front-rear direction is determined. Subsequently, on the right end side, while appropriately moving the right end side of the optical unit 50 in the front-rear direction with the fastening hole 56e on the optical unit 50 side and the fastening hole 1e on the main body frame 1F side, an optical path position adjusting jig (not shown). Align with, and fasten in place with screws. By this operation, the optical unit 50 is positioned with respect to the main body frame 1F. Next, the remaining fastening holes 56c, 56d, 56f on the side of the optical unit 50 and the remaining fastening holes 1c, 1d, 1f on the side of the main body frame 1F are sequentially fastened to move the optical unit 50 to the upper portion of the main body frame 1F. Fixed to.

Further, the optical unit will be described.

As indicated by a path L shown in FIG. 3, the laser light emitted from the semiconductor laser 55 is condensed by the lens 53, folded back by the reflection mirror 54, and is attached to the main body frame 1F inside the process cartridge 40 which is detachable. A latent image is drawn on the photosensitive drum 41.

The optical unit alone is set and adjusted in advance by a laser light irradiation position or a jig.
Therefore, the body frame 1F of the optical unit 50 itself
If the position for the
It is possible to draw a latent image on 1.

The optical frame 56 in the optical unit 50
Has a relationship of V1 <V2 with respect to the volume V2 of the main body frame 1F when its volume is V1, and the shape of the optical frame 56 is generally simpler than that of the main body frame 1F. Therefore, it is effective to determine the material so that the material of the optical frame 56 itself and the material of the main body frame 1F are different so that the optical frame 56 can perform a sufficient strength function as a beam. Further, from the above-mentioned volume relationship, the main body frame 1F
It is possible to suppress the cost increase compared to the case where the strength function is added to. Therefore, in this embodiment, the optical unit 50 is made to have rigidity so as to increase the partial strength of the main body frame 1F.

FIG. 6 shows another structure of the optical unit 50, that is, a structure in which the optical unit 50 directly irradiates the photosensitive drum 41 with laser light without using the reflection mirror 54. Also in the figure, 51, 53, 56
Indicates a polygon mirror, a lens, and an optical frame, respectively. <Embodiment 2> Referring to the embodiment of FIGS.
Will be described. In this embodiment, the optical unit 50A
Therefore, the mirror unit 50B having the reflection mirror 54 is independent. Other configurations are similar to those of the first embodiment.

The present embodiment takes advantage of the advantage that the positional accuracy can be adjusted by the reflection mirror 54, which has been conventionally performed.

As in the first embodiment, the optical position in the optical unit 50A is adjusted in advance. In FIG. 7, the optical unit 50A is positioned by fixing it with screws, and no strict accuracy is required at this time. As shown in FIG. 8, the rigidity of the main body frame 1F is increased by fixing the optical unit 50A.

Next, using an optical adjustment jig (not shown),
The positioning of the body frame 1F and the mirror unit 50B is adjusted. The mirror unit 50B is a main frame 1F.
On the other hand, the position on the left end side is determined by the positioning boss 1b, and the optical path is adjusted by finely adjusting the right end side using an optical path adjusting jig (not shown). As a result, optical adjustment by the mirror unit 50B, which is smaller and easier to handle than the optical unit 50A, becomes possible, and the rigidity of the main body frame 1F by the optical unit 50A can be improved as in the first embodiment. <Third Embodiment> FIG. 9 shows a third embodiment. The same members and the like as those in the first and second embodiments described above are designated by the same reference numerals, and the description thereof will be omitted.

Due to its structure, the main body frame 1F in this embodiment has a left side plate 1L, a right side plate 1R, and a front stay 1S ₁ and a middle stay 1S connecting these side plates 1L, 1R.
₂ , rear stay 1S ₃ , and rear stay 1 in the rear longitudinal direction
It consists of S ₄ . That is, in the main body frame 1F, since the front portion does not have the front stay that faces the rear stay 1S ₄ at the rear portion, the left and right side plates 1L and 1R have insufficient rigidity and are easily deformed. In addition, when the main body frame 1F having the shape of the present embodiment is molded, distortion at the time of molding,
It is difficult to guarantee the positional accuracy of the positioning pins 1h and 1i due to warpage and the like, which is a problem in shortening the molding cycle and improving productivity. In this embodiment, such a problem is solved.

In FIG. 9, reference numeral 57 is an optical stand for mounting the optical unit 50 on the main body frame 1, and is composed of, for example, a pressed sheet metal. The optical bench 57 is positioned by positioning holes 57g, 57h, 57i that fit with the positioning pins 1g, 1h, 1i of the body frame 1F, respectively, and is further coupled to the body frame 1F by fixing screws 58L, 58R.

In the shape of the main body frame 1F in this embodiment, the left-side plate 1L and the right-side plate 1R that are farthest from the front stay 1S ₁ and the back stay 1S ₄ tend to be greatly deformed in the left-right direction. This deformation is corrected by the accuracy of the positioning holes 57g, 57h, 57i of the optical table 57. Deformation (warpage) of the body frame 1F is 1 mm
However, the positioning hole 57 of the optical stand 57
Since the pitch accuracy of g, 57h, and 57i can be guaranteed about ± 0.1 mm, high-accuracy positioning can be guaranteed with the configuration of this embodiment. Positioning hole 57g of optical stand 57
The shapes of 57h and 57i are such that the hole 57g has a circular diameter and the hole 57h for correcting the deformation is a long hole having a long diameter in the front-rear direction, and the left and right side plates 1L, 1R are constrained in the left-right direction to ensure positional accuracy. Further, the position of the optical table 57 in the rotation direction in the horizontal plane can be positioned by making the positioning hole 57i a long hole having a long diameter in the left-right direction.

In the main body frame 1F, the left side plate 1L is made stronger than that of the right side plate 1R, the left side plate 1L is the reference side, and the right side plate 1R is the deformation correcting side. Right side plate 1
The R has a configuration in which rigidity is reduced in order to smoothly correct the dimensions by the optical table 57. This will be described in order below.

Reference numerals 1j and 1k denote elongated holes provided in the right side plate 1R. Further, the right side plate 1R does not have ribs at the portions B ₁ and B ₂ , and has a structure that is easily deformed in the left-right direction. Since the right side plate 1R has low rigidity, a drive system such as a gear unit that requires high rigidity is attached to the left side plate 1L. Further, when the basic thickness of the right side plate 1R is t _R and the basic thickness of the left side plate 1L is t _L , the same effect can be obtained even if t _L > t _R , and the increase in the weight of the main body frame 1F can be suppressed. Is also possible.

By providing the sheet metal optical base 57 as in the present embodiment, the following effects are obtained as compared with the first and second embodiments. (1) Since the optical unit 50 can be downsized, the assembling property and the productivity are improved. (2) Since the optical unit 50 and the main body frame 1F are not directly connected to each other, the deformation of the optical unit 50 is small. (3) By forming the optical bench 57 into a sheet metal, the rigidity of the housing can be further increased. (4) Since the positions of the left and right side plates 1L, 1R of the main body frame 1F are guaranteed by the processing accuracy of the positioning holes 57g, 57h, 57i of the optical table 57 which are processed by a press with high accuracy, the positioning accuracy can be improved. it can. (5) By connecting the optical base 57 made of sheet metal to the ground, it can also be used as a member for shielding harmful electromagnetic waves emitted from the inside of the main body 1.

In the present embodiment, the reference side of the main body frame 1F is the left side plate 1L, but the present invention is not limited to this, and the same effect can be obtained by using the right side plate 1R as the reference side.

Further, in the frame of this structure, the molding die is divided into upper and lower parts, and a tapered shape for the draft is required from the roots of the left and right side plates 1L, 1R to the upper part. Further, since the left and right side plates 1L, 1R are formed by sliding the mold outward in the left-right direction, the body frame 1F after molding may be deformed as shown by the chain double-dashed line in FIG. Therefore, in the present embodiment, the above-described tapered shape for the draft and the deformation due to the sliding of the left and right side plates 1L, 1R are corrected.

When the horizontal pitch between the positioning holes 57g and 57h of the optical base 57 is L ₀ and the horizontal pitch between the positioning pins 1g and 1h of the main body frame 1F is L ₁ , L ₀ <before assembly. There is a relationship of L ₁ , and after assembly, the left and right side plates 1L, 1R of the body frame 1F are corrected so that L ₀ = L ₁ .

When the draft of the side plate of the main body frame 1F is θ and the height from the front stay 1S ₁ to the mounting surface of the optical base 57 is H, the dimension of L ₁ is L ₁ = L ₀ + Hsin θ. If set, the taper shape due to the draft is also corrected.

According to this structure, the draft of the side plate 1L on the reference side can be eliminated, and the distance between the side plates 1L and 1R can be guaranteed over the entire height.
It is possible to position the group of components mounted on the F with high accuracy. <Embodiment 4> Embodiments of the members constituting the process cartridge 40 are not limited to those shown in FIG. For example, an electrophotographic photosensitive member as an image carrier and at least one of a charging unit, a developing unit, and a cleaning unit as a process unit are integrally made into a cartridge and detachable from the main body of the image forming apparatus. May be.

Further, the electrophotographic photosensitive member as the image carrier and the charging means, the developing means, or the cleaning means as the process means are integrally made into a cartridge, and this cartridge can be attached to and detached from the main body of the image forming apparatus. Alternatively, at least the developing means and the electrophotographic photosensitive member as the image bearing member may be integrally formed into a cartridge so as to be detachable from the main body of the image forming apparatus. <Embodiment 5> The first supporting means 10 of the above embodiments may be configured mainly by a paper feed cassette. A vertical cassette mounting portion is provided at the rear portion of the main body 1, and a paper feed cassette containing the recording medium P is mounted from above the cassette mounting portion to support the recording medium P in the vertical direction. is there. In this case, the cassette mounting portion and the paper feed cassette constitute the first supporting means.

[0060]

As described above, according to the present invention,
By connecting the upper portions of the left and right side plates of the body frame with the optical unit, the optical unit can be used as a strength member, so that the number of parts can be reduced and the overall configuration can be simplified.

Further, since the optical unit as the strength member can correct the warp and distortion of the main body frame, it is possible to improve the mounting accuracy of each member mounted on the main body frame.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view illustrating a schematic configuration of an image forming apparatus according to a first exemplary embodiment.

FIG. 2 is an operation explanatory diagram illustrating an opening / closing operation of an outer cover and a process cartridge mounting operation in the first embodiment.

FIG. 3 is a schematic diagram illustrating a state after assembly of the image forming apparatus according to the first exemplary embodiment.

FIG. 4 is a schematic diagram illustrating a state in which each member of the image forming apparatus according to the first exemplary embodiment is disassembled.

FIG. 5 is an exploded perspective view of a main body frame of the image forming apparatus according to the first exemplary embodiment.

FIG. 6 is an exploded perspective view of a main body frame using an optical unit having another configuration.

FIG. 7 is an exploded perspective view of a main body frame of the image forming apparatus according to the second exemplary embodiment.

FIG. 8 is a perspective view illustrating an assembled state of a main body frame of the image forming apparatus according to the second exemplary embodiment.

FIG. 9 is a perspective view illustrating an assembled state of a main body frame of the image forming apparatus according to the third exemplary embodiment.

FIG. 10 is an exploded perspective view of a main body frame of a conventional image forming apparatus.

[Explanation of symbols]

1 Image forming apparatus main body (printer main body) 1F Main body frame 1L Left side plate 1R Right side plate 1S ₁ Front stay 1S ₂ Middle stay 1S ₃ Rear stay 1S ₄ Rear stay 1b Positioning boss 1c, 1d, 1e, 1f Fastening hole 2 Exterior Covers 2e, 3c, 6b Exhaust holes 3 Hood 4 Partition 5 Back plate 6 Rear plate 10 First supporting means 20 Second supporting means 30 Conveying path 40 Process cartridge 41 Image carrier (photosensitive drum) 42 Charging means (transfer roller) 43 Developing means (developing device) 44 Cleaning means (cleaning device) 45 Cartridge container 50, 50A Information light emitting means, optical unit 50B Mirror unit 51 Polygon mirror 53 Lens 56 Optical frame 56L, 56R Mounting portion 56b Positioning holes 56c, 56d, 56e , 56f Fastening hole 60 Transfer Stage 61 transfer roller 70 fixing means 72 the ceramic heater 74 the fixing film 75 pressure roller 76 fixing roller 80 substrate 81 controller 82 AC input portion 83, 85 high voltage generating section 84 motor M image forming apparatus (laser beam printer) P recording medium θ ₁ First support angle θ ₂ Second support angle

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Seietsu Miura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Tatsuo Hamada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Incorporated (72) Inventor Jun Azuma 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yoshihiro Matsuo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (16)

[Claims] 1. An image forming apparatus for forming an image on a recording medium, comprising: first supporting means for vertically supporting a recording medium for feeding; and second supporting means for vertically supporting the recording medium after image formation. Supporting means, an image carrier provided above a transport path from the first supporting means to the second supporting means, and the image carrier between the first supporting means and the second supporting means. An information light emitting unit provided above the image carrier for giving information light corresponding to image information to the image carrier, and a toner image formed on the image carrier provided below the transport path. A transfer unit for transferring to the recording medium, a fixing unit for fixing the toner image transferred to the recording medium on the recording medium, a main body frame having left and right side plates and a connecting member for connecting these left and right side plates , When the upper parts of the left and right side plates are connected And a optical frame that houses the information light emitting means to be, the image forming apparatus characterized by. 2. The body frame is configured by integrally forming the left and right side plates and the connecting member, and the optical frame has a positioning portion and a fixing portion with respect to the left and right side plates. The image forming apparatus according to claim 1. 3. The optical frame has an optical base for connecting left and right side plates of the main body frame, and an optical unit mounted on the optical base and accommodating the information light emitting means. The image forming apparatus according to claim 1 or 2. 4. Of the left and right side plates of the body frame,
The rigidity of the side plate on the non-reference side is set to be lower than the rigidity of the side plate on the reference side when one side is set to the reference side and the other side is set to the non-reference side. The image forming apparatus according to any one of the above. 5. The image forming apparatus according to claim 4, wherein the thickness of the side plate on the non-reference side is set to be smaller than the thickness of the side plate on the reference side. 6. The image forming apparatus according to claim 4, wherein the side plate on the non-reference side is provided with a hole. 7. The draft of the side plate on the reference side is approximately 0 degrees, and the draft of the side plate on the non-reference side is 0.5 to 5 degrees.
The image forming apparatus according to claim 4, wherein the image forming apparatus comprises: 8. The distance L ₁ between the optical base positioning pins projecting from the left and right side plates of the body frame and the pitch L ₀ of the positioning holes of the optical base satisfy L ₁ ≧ L _0. The image forming apparatus according to claim 3, wherein ₁ and L ₀ are set. 9. In the side plate on the non-reference side of the main body frame, if the height from the connecting member to the mounting position of the optical table is H, and the draft of the side plate on the non-reference side is θ,
9. The image forming apparatus according to claim 8, wherein L ₀ , L ₁ , H, and θ are set so that these values satisfy L ₁ ≈L ₀ + Hsin θ. 10. A feeding position for feeding the recording medium supported by the first supporting means, a feeding position for feeding the recording medium supported by the first supporting means, a transfer position by the transferring means, and the fixing means, which are arranged in order from the upstream side to the downstream side of the conveying path. The image forming apparatus according to any one of claims 1 to 9, wherein the fixing position by the means is arranged at a lower position in this order. 11. The image forming apparatus according to claim 1, wherein the information light emitting unit emits a laser beam. 12. The information light emitting means includes a semiconductor laser, a polygon mirror, a lens, and a reflection mirror, and the polygon mirror is supported on the side of the first support means and the reflection mirror is supported on the second side. 12. The image forming apparatus according to claim 11, wherein the image forming apparatus is arranged on the device side, the polygon mirror is arranged below, and the reflection mirror is arranged above. 13. The image carrier comprises an electrophotographic photosensitive member as the image carrier and at least one of a charging unit, a developing unit, and a cleaning unit, which are integrally formed as a cartridge with respect to the main body of the image forming apparatus. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided in a process cartridge that is detachable. 14. The image carrier can be detachably attached to an image forming apparatus main body by integrally forming an electrophotographic photosensitive member as the image carrier and a charging unit, a developing unit, or a cleaning unit into a cartridge. The image forming apparatus according to claim 1, wherein the image forming apparatus is provided in the process cartridge. 15. The image carrier is provided in a process cartridge in which at least a developing unit and an electrophotographic photosensitive member as the image carrier are integrally made into a cartridge and detachable from the main body of the image forming apparatus. The image forming apparatus according to claim 1, wherein: 16. A feeding cassette, wherein the first supporting means stacks and stores recording media and is detachably attached to an image forming apparatus main body, and a cassette attaching portion which holds the feeding cassette in a vertical direction. The image forming apparatus according to any one of claims 1 to 15, further comprising: