JP2649321B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a laser beam printer, and more particularly, to an image bearing means having a photoreceptor on its surface and a device for projecting light having image information onto the photoreceptor of the image carrier. The present invention relates to an image forming apparatus including an optical unit.

[0002]

2. Description of the Related Art An image forming apparatus such as a laser beam printer includes, for example, image bearing means in the form of a rotating drum having a photosensitive body disposed on a peripheral surface thereof, and light having image information on the photosensitive body of the image bearing means. An optical unit for projection is provided. The image bearing means is mounted on an appropriate frame such as a stationary frame or a process unit frame and mounted at a required position. When the frame is a process unit frame, the process unit frame and the image bearing means mounted thereon constitute a process unit detachably mounted on the apparatus main body.

In such an image forming apparatus, the distance between the image bearing means and the optical unit, that is, the relative position in the direction of approaching and separating from each other, is set sufficiently accurately in order to obtain a desired good image. It is also important that the relative position in a direction substantially perpendicular to the approaching and separating directions is sufficiently precise.

[0004]

However, in the conventional image forming apparatus, the structure for setting the relative position between the image bearing means and the optical unit with sufficient precision is extremely complicated, There is a problem that it is difficult to set the relative position between the holding means and the optical unit with sufficient precision.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and its main technical problem is that a relatively simple and inexpensive means is used to relatively move the image bearing means and the optical unit in the direction of approaching and separating from each other. An object of the present invention is to provide a new and excellent image forming apparatus in which a target position is set sufficiently accurately. Another technical problem of the present invention is that the relative positions of the image bearing means and the optical unit in the direction of approaching and separating from each other are set sufficiently accurately by relatively simple and inexpensive means, and the mutual positions of the image bearing means and the optical unit are sufficiently high. An object of the present invention is to provide a novel and excellent image forming apparatus in which the relative position in a direction substantially perpendicular to the approaching and separating directions is set sufficiently accurately.

[0006]

According to one aspect of the present invention, there is provided an image forming apparatus for achieving the above-mentioned main technical object, comprising: an image bearing means mounted on a frame and having a photosensitive member on a surface; and image information. An optical unit for projecting light onto the photoreceptor of the image bearing means, the optical unit being movably mounted over a predetermined range in a direction approaching and separating from the frame, Either the optical unit or the frame is provided with three action pieces protruding toward the other, and the optical unit is elastically biased toward the frame. An image forming apparatus is provided, wherein biasing means for pressing the optical unit against the frame via the three action pieces is provided.

[0007] In order to achieve the above-mentioned other technical problems, a positioning means for substantially matching a specific portion of the frame with a specific portion of the optical unit, and the frame centered on the specific portion are provided. It is preferable to provide a rotation preventing means for preventing relative rotation between the optical unit and the optical unit.

According to another aspect of the present invention, there is provided an image forming apparatus which achieves the above-mentioned other technical problems, includes an image carrying means mounted on a frame and having a photosensitive member on a surface, and a light having image information. An optical unit for projecting the photosensitive member on the photoreceptor, the optical unit being movable over a predetermined range in the direction approaching and separating from the frame, and in the direction approaching and separating from the frame. The optical unit and the frame are movably mounted in a predetermined range in an arbitrary direction substantially perpendicular to the optical unit, and one of the optical unit and the frame has a polygonal outer shape projected toward the other. One protrusion having a shape is provided, and the other of the optical unit and the frame is
The inner shape is a polygonal shape corresponding to the outer shape of the projection, one receiving portion for receiving the projection is provided, and the optical unit is elastically biased toward the frame, so that the projection and An image forming apparatus is provided, wherein biasing means for pressing the optical unit against the frame via the receiving portion in which the optical unit is received is provided.

[0009]

In the image forming apparatus provided by one aspect of the present invention, the optical unit is pressed against the frame via the three action pieces, so that the optical unit is moved between the frame on which the image bearing means is mounted and the optical unit. The relative positions in the directions approaching and separating from each other are set sufficiently accurately. In the image forming apparatus provided according to another aspect of the present invention, the optical unit is pressed against the frame via the projection and the receiving portion in which the projection and the receiving unit receive the optical unit. The relative position in the direction of approaching and separating from the unit is set sufficiently precisely, and the relative position in the direction substantially perpendicular to the direction of approaching and separating from the unit is set sufficiently accurate. .

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a preferred embodiment of a laser beam printer constructed in accordance with the present invention.

First Embodiment of Laser Beam Printer FIGS. 1 to 10 show a first embodiment of a laser beam printer constructed according to the present invention. Referring mainly to FIG. 1 to FIG. 3, the illustrated laser beam printer includes an apparatus main body indicated by reference numeral 2 as a whole. The apparatus main body 2 includes a lower main body 6, and a left portion 6a of the lower main body 6 in FIGS. 1 and 2 projects upward, and an opening / closing housing 4 is provided at an upper right of the lower main body 6. Are openably and closably arranged. An operation panel 10 is provided on the front surface of the left portion 6a of the lower main body 6.

As shown in FIG. 2, a support extending in the front-rear direction (the direction perpendicular to the paper in FIG. 2 and the left-right direction in FIG. 3) is provided inside the upper wall 12 at the left portion 6a of the lower main body 6. The shaft 14 is mounted. On the other hand, a pair of mounting projections 16 (only one of which is shown in FIG. 2) is provided at the upper end of the opening / closing housing 4 at an interval in the front-rear direction. It is installed.
The connecting member 18 has a substantially U-shape as a whole, and a substantially circular hole which is partially open is formed in the center thereof. A pair of protrusions 20 are provided at an intermediate portion of the connecting tool 18,
The connecting tool 18 is mounted on the opening / closing housing 4 by screwing the mounting screw 22 to the mounting protrusion 16 through these projections 20. By positioning the support shaft 14 in the hole of each connecting tool 18 and then screwing the bolts 24 and nuts 26 through both ends of the connecting tool 18, the lower main body 6 is supported via the supporting shaft 14 and the connecting tool 18. The opening / closing housing 4 is pivotally connected. Locking means 28 is also interposed between the lower main body 6 and the opening / closing housing 4. The locking means 28 is mounted in the lower right portion of the opening / closing housing 4 so as to be pivotable between a locked position (a position indicated by a solid line in FIG. 2) and a non-locked position (a position indicated by a two-dot chain line in FIG. 2). Locking member 30 and a locking opening 34 formed in a part of the wall 32 of the lower main body 6. When the opening / closing housing 4 is in the closed position shown by the solid line in FIG. 2, the claw portion of the locking member 30 engages with the locking opening 34 to releasably lock the opening / closing housing 4 in the closed position. When the operating portion 30a of the locking member 30 is pivoted upward through an opening formed in the lower right portion of the opening and closing housing 4, the locking member 30 is positioned at the unlocked position, and the claw portion of the locking member 30 The engagement with the locking opening 34 is released, and the locking means 28 is unlocked. A projection 32a is integrally provided on a part of the wall 32 of the lower main body 6, and the engagement member 30 abuts on the projection 32a to prevent the pivoting movement beyond the unlocked position. When the opening / closing housing 4 is turned in the direction indicated by the arrow 35 after the locking means 28 is unlocked, the opening / closing housing 4 is turned around the support shaft 14 to the open position indicated by the two-dot chain line in FIG. Be positioned.
As can be clearly understood by referring to FIG.
When both ends of the connecting member 18 are relatively strongly tightened by the bolts 24 and nuts 26, the inner surface of the connecting member 18 and the support shaft 14 are tightened.
Is relatively large, and therefore the opening / closing force when opening and closing the opening / closing housing 4 is large. However, when the both ends of the connecting member 18 are relatively weakly tightened by the bolts 24 and the nuts 26, the connecting member The frictional force between the inner surface of the support shaft 14 and the outer peripheral surface of the support shaft 14 is relatively small, so that the opening / closing force when opening and closing the opening / closing housing 4 is reduced.

Continuing the description with reference to FIG. 3, a process unit indicated generally by reference numeral 36 is mounted in the apparatus main body 2. The process unit 36 includes a process unit frame 38 (see also FIGS. 7 and 8), and a rotating drum 40 constituting image bearing means is rotatably mounted on the process unit frame 38. On the peripheral surface of the rotating drum 40, an electrophotographic photosensitive member is disposed. Rotary drum 40 rotated in the direction indicated by arrow 42
Around the photoreceptor, a charging corona discharger 44 for uniformly charging the photoreceptor surface to a specific polarity, a developing device 46 for developing an electrostatic latent image on the photoreceptor surface into a toner image, A transfer corona discharger 48 for transferring a toner image to a sheet member and a cleaning device 50 for removing toner remaining on the surface of the photoconductor after transfer are provided. The charging corona discharger 44, the developing device 46, and the cleaning device 50 are mounted on the process unit frame 38 (the mounting of the process unit frame 38 itself will be described later). On the other hand, the transfer corona discharger 44 is mounted on the lower main body 6 of the apparatus main body 2. The cleaning device 50 includes an elastic blade 52 acting on the surface of the photoconductor, and removes toner remaining on the surface of the photoconductor and collects the toner in the toner collection chamber 54.

An optical unit 56 is provided above the process unit 36. The optical unit 56 includes a laser light source 58 (FIG. 5), a rotating polygon mirror 60 rotated in a predetermined direction, a so-called fθ lens 62, a first reflecting mirror 64, a second reflecting mirror 66, and a cylindrical lens 68. I have. The laser light source 58 irradiates the rotary polygon mirror 60 with laser light based on image information output from a computer, for example. The laser light reflected by the rotary polygon mirror 60 is reflected by the fθ lens 62 as shown by a dashed line arrow in FIG.
Through the first reflecting mirror 64, and the first reflecting mirror 6
After being reflected by the fourth and second reflecting mirrors 66, the light passes through a cylindrical lens 68 and is projected on the surface of the rotating drum 40 in a projection area 70.

Below the process unit 36, a transfer mechanism indicated by reference numeral 72 is disposed. The transport mechanism 72 includes a transport roller pair 76, a guide plate 78, a guide plate 80, a fixing roller pair 82, and a lower discharge roller pair 84 that define a transport path for transporting a sheet member such as plain paper through a transfer area 74. . The upstream end of the transport path is branched into two branch paths. One of the forks extends linearly to the right in FIG.
Are arranged. The other end of the branch path is curved and extends downward, and its upstream end (below the transport mechanism 72, the lower body 6
(Inside), an automatic supply means 88 is provided. The manual feed unit 86 includes a table 90 that can rotate between a supply position illustrated in FIG. 3 and a storage position (not illustrated) that is swung upward. When used, the table 90 is positioned at the supply position. When the sheet member positioned on the table 90 is inserted through the opening 92 defined on the right side of the lower main body 6 in FIG. 3, the sheet member is placed on the lower surface of the guide piece 94 and the inner surface of the wall 95 of the lower main body 6. The guide ridge 96 is guided to the pair of transport rollers 76 through the space between the guide ridge 96 and the upper edge. The automatic supply means 88 includes a cassette 98 in which sheet members are loaded in a stacked state. The cassette 98 is removably attached to a cassette receiving portion 102 defined in the lower main body 6 through an opening 100 formed in the front surface (the left side surface in FIG. 3) of the lower main body 6 (first). See also FIG. 2 and FIG. 2). A feed roller 104 is provided above the cassette receiving portion 102.
Are arranged. When the feed roller 104 is rotated in the direction indicated by the arrow 106, the sheet members in the cassette 98 are sent out one by one, and the sent sheet members are provided on the upright wall portion 108 of the lower main body 6 by a guide. Ridge 110
Then, the sheet is guided by the guide protrusions 96 and guided to the conveying roller pair 76.

The downstream end of the transport path is also branched into two branch paths. In this connection, a part of the opening / closing housing 4, that is, a rectangular opening / closing section 112 on the front surface thereof is shown by a first dashed line in FIG. And a second position indicated by a solid line in FIG. 3. When the opening / closing section 112 of the opening / closing housing 4 is at the first position, the sheet member sent out from the lower discharge roller pair 84 is directly discharged to the outside of the opening / closing housing 4 and the inner surface of the opening / closing section 112 (shown by a two-dot chain line). (In the state, the upper surface).
2 functions as a first receiving unit). On the other hand, the opening and closing unit 1
When the sheet 12 is in the second position, the sheet member sent out from the lower discharge roller pair 84 is further conveyed along the inner surface of the opening / closing section 112, and then the opening / closing housing 4 is operated by the action of the upper discharge roller pair 114. Is discharged to a receiving portion 116 (functioning as a second receiving portion) defined on the upper surface of the sheet.

The operation of the above-described laser beam printer will be outlined below. The rotating drum 40 has an arrow 42
During the rotation in the direction indicated by, the charging corona discharger 44 uniformly charges the photoconductor surface of the rotating drum 40,
Next, in the projection area 70, a laser beam having image information from the optical unit 56 is projected onto the surface of the photoconductor, thus forming an electrostatic latent image corresponding to the image information on the surface of the photoconductor.
Next, the developing device 46 develops the electrostatic latent image into a toner image. Thereafter, the sheet member supplied to the conveyance path from the manual feed unit 86 or the automatic supply unit 88 is brought into contact with the surface of the photoconductor in the transfer area 74, and the toner on the surface of the photoconductor is operated by the corona discharger 48 for transfer. The image is transferred to the sheet member. The sheet member onto which the toner image has been transferred is separated from the rotating drum 40 and is conveyed to the fixing roller pair 82, where the toner image is fixed on the surface of the sheet member.
The sheet member on which the toner image is fixed is a lower discharge roller pair 84.
When the opening / closing section 112 is at the first position, it is discharged onto the opening / closing section 112 as it is. When the sheet member is discharged onto the opening / closing section 112, the third
As can be understood by reference to the figures, the sheet member is ejected with the image formed side up. On the other hand, when the opening / closing portion 112 is at the second position, the sheet member conveyed to the lower discharge roller pair 84 is conveyed further upward, and is defined on the upper surface of the open / close housing 4 by the action of the upper discharge roller pair 114. Is discharged to the receiving portion 116. When the sheet member is ejected onto the receiving portion 116, as will be understood by referring to FIG. 3, the sheet member is ejected with the image formed side down.
The rotating drum 40 continues to rotate further, and the cleaning device 5
By the action of 0, the residual toner is removed from the photoreceptor surface.

The optical unit 56 will be described in detail with reference to FIGS. 4 and 5 together with FIG. 3. The illustrated optical unit 56 includes a box-shaped optical unit frame 120, and the optical unit frame 120 has the above-described structure. An optical element is provided. The optical unit frame 120 includes various walls 122 and 12.
4, 126, 128, 130, 132 and 134 to define a substantially sealed space. Then, the laser light source 58 is mounted on the wall 124, and the rotating polygon mirror 60, the fθ lens 62, the first reflecting mirror 64, the second reflecting mirror 66, and the cylindrical lens 6 are provided in a substantially sealed space.
8 is attached. The walls 132 and 134 have projections 132a and 134a projecting downward, respectively, and define an elongated rectangular projection opening 136 by the projections 132a and 134a. The opening 136 is covered with a transparent glass 138, and the light from the laser light source 58 is projected on the photoreceptor surface of the rotating drum 40 through the transparent glass 138.

The optical unit frame 120 is mounted on the inner surface of the upper wall 140 of the opening / closing housing 4 as follows.
Continuing the description with reference to FIGS. 4 and 6, on the inner surface of the upper wall 140 of the opening / closing housing 4, three bosses 142 projecting inward are integrally formed. A single boss 142 is formed on the right end of the upper wall 140 in FIG. 4, and the boss 142 is formed on the left end of the upper wall 140 in the direction perpendicular to the paper of FIG. Is 2
Individually formed. Female screw holes are formed in these boss portions 142. Also, four ridges 144 are provided on the outer peripheral surface of the boss portion 142 so as to protrude outward.
Has a stepped portion. On the other hand, the optical unit frame 12
Support projections 146 and 148 protruding outward are integrally formed on the wall 126 and the wall 128 of the zero. The support projection 146 has one hole 15 corresponding to one boss 142.
0 is formed, and two bosses 1 are formed on the support protrusion 148.
Two holes 152 are formed corresponding to. 4th
As clearly shown in the figures and FIG.
Through the holes 150 and 152 formed in the upper wall 14
By screwing the mounting screw 154 onto the boss portion 142 of the optical unit 120, the optical unit frame 120, and thus the optical unit 56
Is mounted on the inner surface of the upper wall 140. In this mounting state, the optical unit frame 120 is vertically moved in FIGS. 4 and 6, and the support protrusions 146 and 148 are
2 and a position where the support protrusions 146 and 148 are in contact with the head of the mounting screw 154, that is, in a direction approaching and separating from the process unit 36. The outer diameter of the shaft of the mounting screw 154 is smaller than the inner diameters of the holes 150 and 152 formed in the optical unit frame 120. Therefore, the optical unit frame 120 is in the horizontal direction, that is, in the horizontal direction in FIG. (In the direction perpendicular to the paper surface in FIG. 6) and in the direction perpendicular to the paper surface in FIG. . Optical unit frame 1
20 further includes a biasing coil spring 1 constituting biasing means.
56 are provided. The biasing coil spring 156 is interposed between the step of the ridge 144 on each of the bosses 142 and the support protrusions 146 and 148. The biasing coil spring 156 elastically biases the optical unit frame 120 downward in FIGS. 4 and 6, in other words, in a direction approaching the process unit 36 located below (ie, the opening / closing housing 4 is in the open position). When the optical unit frame 120 is positioned, the optical unit frame 120 is held at a position where the supporting protrusions 146 and 148 abut against the head of the mounting screw 154).

The optical unit frame 120 is also provided with a static elimination lamp (not shown). As shown in FIG. 4, on the lower surface of the support protrusion 148 of the optical unit frame 120, a lamp housing 158 is attached by a mounting screw 160.
Is mounted, and a static elimination lamp is provided in the lamp housing 158. The static elimination lamp irradiates the rotating drum 40 through a static elimination opening 164 (FIGS. 4 and 7) formed in the upper wall 162 of the process unit 36 to eliminate the residual charges existing on the photoconductor.
If desired, a so-called blank lamp for eliminating charges in the non-image forming area on the photoreceptor is provided in the optical unit frame 12.
0 can also be provided.

Next, the process unit 36 and its mounting mode will be described with reference to FIGS. 7 and 8 together with FIG. The process unit frame 38 of the process unit 36 is formed with a pair of end walls 166 and 168 that are disposed at intervals in the horizontal direction (the direction perpendicular to the paper in FIGS. 3 and 8 and the vertical direction in FIG. 7). (See also FIG. 6), and the upper surface between the pair of end walls 166 and 168 is covered by the upper wall 162. Upper wall 1
62, an elongated exposure opening 17 through which light from the optical unit 56 is allowed to pass, together with the charge removal opening 164.
0 is formed. Between the pair of end walls 166 and 168 of the process unit frame 38, a rotary drum 40 located at a substantially central portion in the left-right direction in FIGS. 3 and 8 is arranged, and one side of the rotary drum 40, that is, A developing device 46 located on the right side in FIGS. 3 and 8 and a cleaning device 50 located on the other side of the rotary drum 40, that is, a left side in FIGS. 3 and 8 are provided.

The developing device 46 is, as shown in FIG.
A developing housing 174 is provided which defines a developing chamber 172 for storing a developer. A portion of the developing housing 174 facing the rotating drum 40 is open, and a magnetic brush mechanism 176 is provided in such a portion. The magnetic brush mechanism 176 includes a hollow sleeve 178 rotated in a direction indicated by an arrow 177 and a stationary permanent magnet 179 disposed in the hollow sleeve 178, and the developer is magnetically held on the surface of the hollow sleeve 178. To the surface of the photoreceptor of the rotating drum 40. In the upper right end of the developing housing 174 in FIG.
82 are provided. A toner discharge opening is provided at the bottom of the toner container 182, and a toner supply roller 184 is provided at the toner discharge opening. When the toner supply roller 184 is rotated in a predetermined direction, the toner storage chamber 1
The toner in 80 is supplied to the developing chamber 172. Developing room 1
A stirring means 186 rotated in a direction indicated by an arrow 173 is also provided in 72, and the stirring means 186 stirs the developer in the developing chamber 172 and frictionally charges the toner in the developer. A plurality of guide protrusions 188 (only one of them is shown in FIG. 3) are provided on the lower surface of the bottom wall of the developing housing 174 at intervals in a direction perpendicular to the paper surface of FIG. These guide projections 188 define the upper side of the transport path between the transport roller pair 76 and the transfer area 74.

The above-described process unit 36 is detachably mounted on the lower main body 6 of the apparatus main body 2 as follows. Continuing the description with reference to FIGS. 7 and 8,
A pair of vertical substrates 190 and 192 are arranged in the lower main body 6 at the above-mentioned horizontal intervals. Vertical board 1
90 is divided into two pieces 190a and 190b in the front-rear direction (the left-right direction in FIG. 7).
A support pin 194 protruding inward is implanted on the inner surface of the support pin 1a.
96 are planted. A pair of support pins 198 and 200 projecting inward at intervals in the front-rear direction are also implanted on the inner surface of the vertical substrate 192. On the other hand, on the outer surface of one end wall 166 of the process unit frame 38, supported projections 202 and 204 are provided corresponding to the support pins 194 and 196, and on the outer surface of the other end wall 168,
The supported projections 206 corresponding to the support pins 198 and 200
And 208 are provided. Supported projections 202 and 2
The lower surface of 06 is substantially flat, and a pair of knob protrusions 210 protruding upward is provided on the upper surface thereof.
Arc-shaped receiving portions are defined on the lower surfaces of the supported projections 204 and 208. The receiving portions defined by the supported protrusions 204 and 208 on one side of the process unit frame 38 are positioned on the support pins 196 and 200 (constituting one support means), and the supported protrusions 202 and 206 on the other side. Are positioned on the support pins 194 and 198 (which constitute the other support means), whereby the process unit frame 38 is detachably mounted between the vertical substrates 190 and 192. In such a mounted state, the cylindrical support pins 196 and 200 are supported by the supported projections 204 and 208.
Of the vertical substrate 190
And 192, the horizontal movement of the process unit frame 38 in FIGS. 7 and 8 is reliably restrained.
Further, as shown in FIG.
An elastic piece 212 such as a leaf spring is provided at a portion of the end wall 168 where the tip of the support pin 200 acts. Accordingly, in the mounting state as described above, the elastic piece 212 acts on the process unit frame 38 to resiliently bias the process unit frame 38 downward in FIG. 7, and the end wall 166 of the process unit frame 38 is supported by the support pin 196. The process unit frame 38 is thus held at the position shown by the solid line in FIG. Further, in the mounted state as described above, the process unit frame 38 is rotatable around the support pins 196 and 200 (constituting the rotation center axis). Accordingly, the user grips the knob 210 of the supported protrusion 202 and / or 206 and lifts the knob to move the process unit frame 38 in the direction indicated by the arrow 2.
It is possible to turn in the direction indicated by 14, for example, to the position indicated by the two-dot chain line in FIG.

Process unit 36 and optical unit 56
Positioning means and rotation preventing means are provided for mutual positioning between the two. Referring to FIG. 4, FIG. 6 and FIG. 7, the positioning means in the illustrated embodiment comprises a combination of a positioning projection and a positioning receiving portion for removably receiving the positioning projection. The optical unit frame 122 includes a cylindrical positioning pin 226 provided integrally on the lower surface of the wall 132 of the optical unit frame 122, and the positioning receiving portion is provided on a circular projection 218 provided integrally on the upper surface of the upper wall 162 of the process unit frame 38. Specified receiving hole 2
22. Positioning pin 226 and receiving hole 2
By providing the circular projection 218 that defines the optical unit 22 integrally with the optical unit frame 122 and the process unit frame 38, respectively, the mutual positioning of the optical unit frame 260 and the process unit frame 38 described later can be performed with sufficient precision. it can. The receiving hole 222 is a circle having an inner diameter corresponding to the outer diameter of the positioning pin 226. When the open / close housing 4 is set to the closed position, the positioning pin 226 is positioned in the receiving hole 222.
6 specific portions (that is, portions where the receiving holes 222 are provided)
And the specific portion of the optical unit frame 120 (that is, the portion where the positioning pin 226 is implanted) substantially matches in the vertical direction. In order to facilitate positioning of the positioning pin 226 in the receiving hole 222, as shown in FIGS. 4 and 6, the tip of the positioning pin 226 is tapered, and the opening end of the receiving hole 222 is inward. It is preferable to incline downward toward. Receiving hole 22 for defining positioning receiver
7 is preferably provided in the vicinity of the exposure opening 170 as shown in FIG. 7, whereby the projection opening 136 in the optical unit 56 and the exposure opening 170 in the process unit 36 are defined with sufficient precision. It can be a positional relationship. The rotation preventing means in the illustrated embodiment is composed of a combination of a rotation preventing protrusion and a rotation preventing receiving portion for removably receiving the rotation preventing protrusion, and the rotation preventing protrusion is formed on the wall 132 of the optical unit frame 120. The lower surface of the process unit frame 38 includes a cylindrical rotation prevention pin 228 integrally provided on the lower surface.
It comprises an elongated receiving hole 224 defined by a protruding portion 220 provided integrally on the upper surface of 62. The receiving hole 224 has a width corresponding to the outer diameter of the rotation preventing pin 228 and is elongated in the left-right direction in FIG. 6 and the up-down direction in FIG. 7 (ie, a direction substantially perpendicular to the center axis of rotation of the opening / closing housing 4). When the opening / closing housing 4 is extended to the closed position, the rotation preventing pin 228 is positioned in the elongated receiving hole 224, and thus the process unit frame 38 and the optical unit frame 122 centered on the positioning pin 226. Relative turning motion is prevented. In order to facilitate the positioning of the rotation preventing pin 228 in the receiving hole 224, as shown in FIG. 6, the tip of the rotation preventing pin 228 is tapered and the opening end of the receiving hole 224 is formed. It is preferable to incline downward toward the inside. Regarding positioning means,
Contrary to the case described above, a positioning projection may be provided on the process unit frame 36 and a positioning receiving portion may be provided on the optical unit frame 122. Similarly, with respect to the rotation preventing means, the process unit frame 3
6 may be provided with a rotation prevention protrusion, and the optical unit frame 122 may be provided with a rotation prevention receiving portion.

Further, in order to hold the process unit frame 38 and the optical unit frame 122 at a predetermined interval in the vertical direction, three action pieces 230 are provided on the optical unit frame 122. One action piece 230 is a substantially triangular piece provided at the end of the wall 134, and the process unit frame 38
4 at the right end in FIG. The other two action pieces 230 are cylindrical pins provided at intervals in the lateral direction (the direction perpendicular to the paper surface in FIG. 4, the horizontal direction in FIG. 6) on the support protrusion 148,
It acts on the left end of the upper wall 162 of the process unit frame 38 in FIG. When the opening / closing housing 4 is moved to the closed position, the working piece 230 of the optical unit frame 122 is moved.
Are brought into contact with the upper wall 162 of the process unit frame 38, and the process unit frame 38 and the optical unit frame 122 are set to a predetermined distance sufficiently precisely.

Next, a part of the drive system of the illustrated laser beam printer will be described mainly with reference to FIGS. 9 and 10. The laser beam printer includes an electric motor 238 that constitutes a main drive source in a drive system of the apparatus main body 2, and the electric motor 238 is mounted on an outer surface of the vertical substrate 192. The output shaft of the electric motor 238 penetrates the vertical board 192 and protrudes inward, and an output gear 254 is fixed to this protruding portion. The auxiliary plate 2 is provided inside the vertical substrate 192 (left side in FIG. 10).
40, and a gear train 242 is mounted. More specifically, support shafts 244 and 246 are mounted between the vertical substrate 192 and the auxiliary plate 240, a gear member 248 is rotatably mounted on the support shaft 244, and a gear member 250 is rotatable on the support shaft 246. It is attached to. Gear member 2
The 48 large gear 252 is the output gear 25 of the electric motor 238.
4 and the small gear 256 of the gear member 248 is meshed with the large gear 258 of the gear member 250. Also,
A gear 262 is provided on the support shaft 260 implanted on the auxiliary plate 240.
(Which constitutes a drive member in the drive system) is rotatably mounted, and this gear 262 is a small gear 26 of the gear member 250.
4 is engaged. The support plate 240 further includes a support shaft 26.
6 and 268 are implanted, and the support shafts 266 and 26
8, gear members 270 and 272 are rotatably mounted, respectively. The small gear 274 of the gear member 270 is meshed with the gear 262, and the large gear 276 is
Of the small gear 278. Accordingly, when the electric motor 238 is energized and the output gear 254 is rotated in the direction indicated by the dashed arrow 280, the gear members 248 and 250,
The gear 262 and the gear members 270 and 272 are rotated in directions indicated by solid arrows, respectively.

On the end wall 168 of the process unit frame 38, a gear train 282 constituting driving means of the process unit 36 is mounted. More specifically, the end wall 168
Has a short shaft 284 implanted therein, and the short shaft 284 has a gear 2
86 is rotatably mounted. A gear 290 is fixed to a portion of the shaft 288 provided on the hollow sleeve 178 (FIG. 3) of the magnetic brush mechanism 176 and protruding through the end wall 168.
6 is engaged. Further, the shaft 29 of the stirring means 186
2, a portion protruding through the end wall 168 is provided with a gear 29
4 is fixed, and the gear 294 is also meshed with the gear 286. A gear 296 (which constitutes a driven member of the driving means) is also provided at the right end of the rotary drum 40 in FIG.

When the process unit 36 is mounted as required, as shown in FIGS. 9 and 10, the gear 296 provided on the rotary drum 40 meshes with the gear 262 in the gear train 242, and the gear 296 in the gear train 282. Gear 2
86 is the large gear 2 of the gear member 272 in the gear train 242
98. Accordingly, when the electric motor 238 is energized, the gear 296 (therefore, the rotary drum 40) is rotated in the direction shown by the arrow 42 via the gear train 242 provided on the auxiliary plate 240, and the gear 290 (therefore, the gear 290) Hollow sleeve 178) and gear 294 (hence stirring means 186)
Are rotated in the directions indicated by arrows 177 and 173, respectively (see also FIG. 3).

Next, the opening / closing operation of the opening / closing housing 4 and the attaching / detaching operation of the process unit 36 will be described mainly with reference to FIGS. 2 and 3. To open the opening / closing housing 4, the lock by the locking means 28 is released and the opening / closing housing 4 is turned in the direction indicated by the arrow 35. When the locking member 30 of the locking means 28 is set to the unlocked position shown by the two-dot chain line in FIG. 2, the engagement between the locking member 30 and the locking opening 34 formed in the lower main body 6 is released. . Thereafter, when the open / close housing 4 is lifted upward, the open / close housing 4 is pivoted about the support shaft 14 in the opening direction indicated by the arrow 35, and is positioned at the position indicated by the two-dot chain line in FIG. When the open / close housing 4 is moved to the open position, the upper part of the process unit 36 is opened, and a part of the transport path is opened and the process unit 3 is opened.
6 is allowed.

Referring to FIGS. 7 and 8, to open a part of the transport path (ie, below the rotary drum 40), the supported portion 202 provided on the process unit frame 38 is required. And / or 206 may be picked up and lifted upwards. As a result, the process unit frame 38 is pivoted about the support pins 196 and 200 in the direction indicated by the arrow 214 (FIG. 8).
By turning to the position shown by the two-dot chain line in the figure, a part of the transport path is opened. Thus, when the sheet member is clogged in a part of the conveyance path, particularly in a region from below the rotary drum 40 to the fixing roller pair 82, the clogged sheet member can be easily removed. To detach the process unit 36, the process unit frame 38 may be taken out through a space created by moving the opening / closing housing 4 to the open position. When the process unit frame 38 is lifted upward, the supported portion 20
2, 204, 206 and 208 respectively support pins 194,
196, 198 and 200 and the gear 29
6 and 286 are disengaged from the gear 262 and the large gear 298 of the gear member 272, respectively.

When mounting the process unit 36,
With the open / close housing 4 positioned at the open position, the supported portion 20 provided on the process unit frame 38 is
2, 204, 206 and 208 are positioned on corresponding support pins 194, 196, 198 and 200, respectively. When the process unit 36 is detachably mounted on the lower main body 6, the driving means provided on the process unit frame 38, that is, the gear 296 and the gear 286 are attached to the auxiliary plate 240 as shown in FIGS. The driving mechanism provided, ie, the gear 262 and the large gear 29 of the gear member 272
8 is drivingly connected. Thereafter, the opening / closing housing 4 is pivoted from the open position in the direction opposite to the direction indicated by the arrow 35 to the closed position indicated by the solid line in FIG. 2 together with FIGS. Thus, the locking member 30 is engaged with the locking opening 34, and the opening / closing housing 4 is releasably locked in the closed position by the action of the locking means 28. When the opening / closing housing 4 is moved to the closed position, as shown in FIGS. 4 and 6, the positioning pins 226 and the rotation preventing pins 228 provided on the optical unit frame 120 are moved to the vertical substrates 190 and 192, respectively. 7) are positioned in the receiving holes 222 and 224 defined in the upper wall 162 of the process unit frame 38 mounted therebetween. Thus, since the outer diameter of the positioning pin 226 is substantially equal to the inner diameter of the receiving hole 222, the unit frame 38 and the optical unit frame 1
The 20 specific portions (the vicinity of the projection opening 136 in the optical unit frame 120 and the vicinity of the exposure opening 170 in the process unit frame 38) are aligned vertically. Further, since the outer diameter of the rotation preventing pin 228 and the width of the receiving hole 224 are substantially equal, the optical unit frame 12 centered on the positioning pin 226 with respect to the process unit frame 38
Zero relative rotation is prevented. Thus, the optical unit 56 is positioned as required above the process unit 36, and the receiving portion 116,
That is, the upper wall 140 of the opening / closing housing 4 is located. In the final stage of the process of bringing the opening / closing housing 4 to the closed position, as clearly understood by referring to FIGS. 4 and 6, the action piece 230 provided on the optical unit frame 120 is moved to the process unit frame 38. Acts on the upper surface of the upper wall 162 (one action piece 230 is
2 and acts on the right end in FIG.
0 acts on the left end of the upper wall 162 in FIG. 4),
The optical unit frame 120 is raised somewhat against the biasing force of the biasing coil spring 156. Thus, the optical unit 56 is pressed against the process unit 36 via the action piece 230, and the interval between the process unit 36 and the optical unit 56 is set to be constant.

When the process unit 36 is mounted, the driving means (particularly the gear 296) in the process unit 36 is used.
When the drive system (especially the gear 262 and the large gear 298 of the gear member 272) in the lower main body 6 is not drive-coupled as required (the peaks of the teeth come into contact with each other), the process unit 36 8 together with FIGS. 3 and 7, the optical unit 56 is also somewhat higher than the position shown in the drawing against the biasing force of the biasing coil spring 156. It is moved to. However, when the electric motor 238 is energized in performing the image forming process, the drive system (especially the gear 296 and the gear 286) and the drive means (especially the gear) in the process unit 36 are rotated by the rotation of the drive system in the lower main body 6. 262 and the large gear 298 of the gear member 272 can be engaged with each other, and the drive means and the drive system are driven and connected as required by the action of the biasing coil spring 156 acting on the process unit 36. 56 is lowered to the illustrated position,
It is maintained in such a position.

In the illustrated image generating apparatus, as shown in FIGS. 3 and 4, the upper wall 140 (that is, the portion defining the receiving portion 116) of the opening / closing housing 4 closed at the closed position is shown in FIG. 4, and extends from left to right (that is, toward the downstream side in the sheet member discharge direction) at a first angle θ (FIG. 3) with respect to the horizontal direction. The optical unit frame 120 mounted on the inner surface of the upper wall 140 is also disposed substantially parallel to the upper wall 140 and inclined with respect to the horizontal direction. In the optical unit frame 120, the laser light from the laser light source 58 is reflected by the rotary polygon mirror 60, guided to the lower left in FIG. 3 and downward in FIG. 5, and reflected by the first reflecting mirror 64. After reaching the second reflecting mirror 66, the light is reflected by the second reflecting mirror 66, passes through the transparent glass 138, and is
Leads to. The main part of the optical path of the optical unit 56, that is, the longest part extending linearly without bending from the rotary polygon mirror 60 to the first reflecting mirror 64 is the optical unit frame 120 shown in FIG. 4, and extends substantially parallel to the optical unit frame 120 and the upper wall 140 from the right end to the left end in FIG. Accordingly, there is substantially no useless space between the upper wall 140 of the opening / closing housing 4 and the optical unit frame 120, and the size of the entire apparatus can be reduced. 3 and 4 of the optical unit frame 120.
In the figure, the distance in the left-right direction (horizontal direction) can be reduced, and a part of the device is slightly higher, but the third device of the entire device is
The size in the left-right direction in the figure can be significantly reduced. The first angle θ (FIG. 3) is preferably set to approximately 45 degrees in consideration of the discharge property of the sheet member received in the receiving portion 116, the downsizing of the entire apparatus, and the like. Further, it should be noted that since the main part of the optical path of the optical unit 56 is inclined, a relatively large space is created on one side of the rotating drum 40, that is, on the right side in FIGS. The developing device 46 is disposed in such a relatively large space, and the developing chamber 172 of the developing device 46 is
, And the toner storage chamber 180 is
It is located outside the developing chamber 172 away from 0. Therefore, the space where the toner storage chamber 180 is located, that is, the space below the right end in FIGS. 3 and 4 of the optical unit frame 120 is relatively large even though the entire apparatus is small. By effectively using the unit as the toner storage chamber 180, a relatively large amount of toner can be stored.

It is preferable that an auxiliary receiving member 300 is provided on the receiving portion 116 (the inclined portion of the upper wall 140 of the opening / closing housing 4) as shown in FIGS. The auxiliary body 300 is formed of a plate-shaped member, and has a plurality of ridges 302 provided on one side thereof at intervals in the left-right direction in FIG. 2 and the direction perpendicular to the paper surface in FIG. The auxiliary body 300 is rotatably mounted on the downstream end of the upper wall 140 in the sheet member discharging direction via a shaft member 304. When an image is formed on a sheet member having a long length in the transport direction, the auxiliary receiver 300 is received at a receiving position indicated by a solid line in FIG. 3 together with FIGS. When the image is formed on a sheet member having a short length in the conveyance direction, the auxiliary receiver 300 is moved to the third position. It can be positioned at a storage position indicated by a two-dot chain line in the drawing (a position rotated from the receiving position by approximately 180 degrees in a direction indicated by an arrow 306 in FIG. 3).

Second Embodiment of Laser Beam Printer FIGS. 11 to 14 show a second embodiment of a laser beam printer constructed according to the present invention. In the second embodiment, the positioning means and the rotation preventing means are formed of a common member.

Referring mainly to FIGS. 11 and 12, the process unit 4 in the second embodiment will be described.
02 also has a process unit frame 404, and between the pair of end walls 406 and 408 (see also FIG. 13) of the process unit frame 404, the rotary drum 410 and the developing device are provided in the same manner as in the first embodiment. (Not shown) and a cleaning device (not shown). Supported protrusions 412 and 414 that constitute supported means are provided on both side ends (left and right ends in FIGS. 11 and 12) of the process unit frame 404. The supported projections 412 and 414 respectively protrude leftward and rightward in FIGS.
6 extend in the mounting direction of the process unit frame 404. On the other hand, the apparatus main body 418 (in the second embodiment, which is not constituted by the lower main body and the opening / closing housing, cannot open and close the wall 422 on which the optical unit 420 is mounted) is provided in FIG. 11 and FIG. In FIG. 12, a pair of support means is provided at intervals in the left-right direction.
Such a pair of support means is composed of substantially L-shaped support rails 424 and 426, and the supported protrusions 412 and 414 of the process unit frame 404 are supported by the support rails 424 and 42.
6 is slidably supported in the direction indicated by arrow 416. The process unit 402 is detachably mounted on the apparatus main body 418 by opening the openable and closable cover member (not shown) present in the apparatus main body 418 on the front side in FIG. 11 (the lower side in FIG. 12). .

In the second embodiment, the upper wall 428 of the process unit frame 404 is further provided with an elongated rectangular projection 430 projecting upward.
30 defines an elongated rectangular exposure opening 432. Open ends of both side edges of the opening 432 in the protrusion 430 are inclined downward inward. on the other hand,
The optical unit frame 434 of the optical unit 420 is provided with an elongated rectangular projection 436 projecting downward. An elongated rectangular projection opening 438 communicating with the exposure opening 432 is defined in the projection 436. The lower ends of both side surfaces of the protruding portion 436 are inclined downward inward in accordance with the shape of the opening end portions on both side edges of the protruding portion 430 of the process unit frame 404. In the second embodiment, the projection 436 of the optical unit frame 434 acts as a polygonal projection, and the process unit frame 404
The opening of the exposure opening 432 serves as a polygonal receiving portion, and constitutes a positioning means and a rotation preventing means. In addition, the protruding portion 436 of the optical unit frame 434 also functions as an operating piece, and as is easily understood by comparing FIGS. 4 and 6 with FIGS. 11 and 13, FIG. Two working pieces located on the left side are omitted in the second embodiment. Other configurations in the embodiment of FIG. 2 are substantially the same as those of the first embodiment, and a detailed description thereof will be omitted.

The process unit 402 is connected to the apparatus main body 418.
In order to removably mount the process unit frame 404, the cover members (not shown) are opened, and the supported protrusions 412 and 414 of the process unit frame 404 are supported by the support rails 424 and 42.
6, the process unit frame 404 can be moved in the mounting direction indicated by the arrow 416 by pressing the grip 440 (FIGS. 11 and 12) of the process unit frame 404. As clearly shown in FIG. 14, the protrusion 430 of the process unit frame 404 is provided.
At one end (the upper end in FIG. 12 and the left end in FIG. 14), an inclined surface 442 that is inclined downward in the mounting direction indicated by an arrow 416 is provided. Is moved in the direction indicated by the arrow 416, the action of the inclined surface 442 causes the optical unit 420 to move somewhat upward against the biasing action of the biasing coil spring 444, and thus the process unit 402 is smoothly mounted. can do.

When the process unit frame 404 is inserted to the predetermined mounting position, it is shown by a solid line in FIG. 14 (in FIG. 14, the optical unit frame 434 is moved with respect to the process unit frame 404 in reverse to the actual situation. As described above, the distal end of the protrusion 436 in the optical unit frame 434 is received in the opening of the protrusion 430 in the process unit frame 404, and thus the protrusion 436 and the receiving portion defined in the opening of the protrusion 430. By the cooperative action, the specific portion of the optical unit 420 and the specific portion of the process unit 402, that is, the projection opening 43 in the optical unit 420.
8 and the portion defining the exposure opening 432 in the process unit 402 are aligned in the vertical direction. Since the protruding portion 436 and the receiving portion defined by the protruding portion 430 have an elongated rectangular shape, they are prevented from relatively rotating when they are engaged with each other. Therefore, in the second embodiment, similarly to the first embodiment, the optical unit 420 moves in the horizontal direction (first
1 (in the left-right direction and the direction perpendicular to the paper surface) over a predetermined range.
Is moved to the predetermined mounting position, the protrusion 436 engages with the receiving portion defined by the protrusion 430,
Specific part of optical unit 420 and process unit 40
2 and the relative rotation of the two is reliably prevented, and thus the optical unit 420
The process unit 402 and the process unit 402 are directly held in a predetermined positional relationship via a protrusion 436 serving as a positioning unit and a rotation preventing unit, and a receiving unit defined by the protrusion 430. In addition, as shown in FIG.
The operation piece 448 provided on the process unit frame 4
04 acts on the upper surface of the upper wall 450 (FIG. 12), and the lower surface of the projection 436 of the optical unit frame 434 acts on the upper surface of the projection 430 of the process unit frame 404. It is raised somewhat against the biasing force. Therefore, the optical unit 4 is provided via the working piece 448 and the protrusion 436 which also functions as the working piece.
20 is pressed by the process unit 402, and the vertical distance between the optical unit 420 and the process unit 402 is set sufficiently accurately.

Third Embodiment of Laser Beam Printer FIG. 15 shows a third embodiment of the laser beam printer constructed according to the present invention. In the third embodiment, the process unit is moved in a direction perpendicular to the axial direction of the rotating drum and mounted on the apparatus main body.

Process unit 5 in the third embodiment
02, the process unit 502 also includes a process unit frame 504, and a pair of end walls 506 (only one of which is shown in FIG. 15) of the process unit frame 504 is shown in FIG. A supported projection 508 extending in the left-right direction is provided. On the other hand, the apparatus main body 510 is provided with a support rail (not shown) constituting a support means corresponding to the supported projection 508. A cover member 512 is provided at a portion defining the right side surface of the apparatus main body 510 in FIG. 15, and an upper end portion of the cover member 512 is rotatably connected. Therefore, the cover member 512 is pivotable between a closed position indicated by a solid line and an open position indicated by a two-dot chain line in FIG.

Further, also in the third embodiment, an elongated rectangular projection 514 is formed on the upper wall of the process unit frame 504.
The projection 514 defines a rectangular exposure opening 516. Also, the optical unit 51
The optical unit frame 520 is provided with an elongated rectangular projection 522 projecting downward.
An elongated rectangular projection opening 524 is defined at 22. The opening of the exposure opening 516 in the projection 514 functions as a polygonal receiving portion, and the tip of the projection 522 functions as a polygonal projection, and constitutes positioning means as in the second embodiment. It constitutes a rotation preventing means. In addition, the protruding portion 522 of the optical unit frame 520 also functions as an operation piece for keeping the interval with the process unit frame 504 constant. Projection 51 of process unit frame 504
An inclined surface 528 that is inclined downward in the mounting direction indicated by the arrow 526 is provided on one side (the side located downstream in the mounting direction indicated by the arrow 526) in FIG. Other configurations in the third embodiment are substantially the same as those in the first embodiment.

In the third embodiment, the process unit 5
02 can be detachably attached to the apparatus main body 510 by turning the cover member 512 in the direction indicated by the arrow 530 to the first position.
5, the support projection 508 of the process unit frame 504 is positioned on a support rail (not shown) and moved in the mounting direction indicated by the arrow 526. When the process unit 502 is moved, the inclined surface 528 provided on the protrusion 514 of the process unit frame 504 is changed to the protrusion 52 of the optical unit frame 520.
2, the optical unit 518 is slightly moved upward against the biasing action of the biasing coil spring 532, and thus the mounting of the process unit 502 can be performed smoothly.

When the process unit 502 is inserted to the predetermined mounting position, the projecting piece 534 provided on the process unit frame 504 comes into contact with the stop member 536 of the apparatus main body 510 as shown by a solid line in FIG. Movement of 502 beyond the mounting position is prevented. Then, the protruding portion 5 in the optical unit frame 520
22 is received in the opening of the protrusion 514 in the process unit frame 504, and thus the protrusion 522 and the protrusion 51
The specific part of the optical unit 518 and the specific part of the process unit 502, that is, the part that defines the projection opening 524 in the optical unit 518 and the part in the process unit 502, cooperate with the receiving part defined in the opening of the optical unit 518. The portion defining the exposure opening 516 is matched in the vertical direction. Since the receiving portions defined by the protruding portion 522 and the protruding portion 514 have an elongated rectangular shape, when the protruding portion 522 is received in the receiving portion of the protruding portion 514, the relative rotation between the two is prevented. Therefore, also in the third embodiment, similarly to the first embodiment, the optical unit 518 includes the mounting screw 538.
Through the predetermined range in the horizontal direction (the left-right direction and the direction perpendicular to the paper surface in FIG. 15)
When the process unit 502 is positioned at the predetermined mounting position, the specific portion of the optical unit 518 and the specific portion of the process unit 502 are matched by engaging the protrusion 522 and the receiving portion of the protrusion 514, and
Rotation relative to both is prevented, and thus the optical unit 5
18 and the process unit 502 are connected to the projection 522 and the projection 514 which function as positioning means and rotation preventing means.
Is directly held in a predetermined positional relationship via the receiving portion. Further, the operation piece 540 provided on the optical unit frame 520 acts on the upper wall of the process unit frame 504, and the lower surface of the projection 522 of the optical unit frame 520 acts on the upper surface of the projection 514 of the process unit frame 504, The optical unit 518 is raised somewhat against the biasing force of the biasing coil spring 532. Therefore, the optical unit 518 is provided via the working piece 540 and the protrusion 522 which also functions as the working piece.
Is pressed by the process unit 502, and the vertical distance between the optical unit 518 and the process unit 502 is also set sufficiently accurately.

In the second embodiment and the third embodiment, the projections (portions defining the projection openings) provided on the optical unit frame are the projections (portions defining the exposure openings) of the process unit frame. However, on the contrary, the projection of the process unit frame may be configured to be received by the projection of the optical unit frame (the portion defining the receiving portion). it can. Further, separately from the projection opening and the exposure opening, polygonal projections and receiving portions functioning as positioning means and rotation preventing means may be provided in the optical unit and the process unit.

Fourth Embodiment of Laser Beam Printer FIG. 16 shows a fourth embodiment of the laser beam printer constructed according to the present invention. In the fourth embodiment, the optical unit is mounted on the lower main body of the apparatus main body,
A main part of the conveying means for conveying the sheet member and a process unit are mounted on an opening / closing housing which is openably / closably mounted on the lower main body.

The laser beam printer of the fourth embodiment has an apparatus main body 602, and the apparatus main body 602 is connected to a lower main body 603 via a shaft member 604 at the right end of the lower main body 603 in FIG. And an opened / closed housing 606. Openable housing 606
Is a closed position indicated by a solid line in FIG. 16 (the various components mounted on the apparatus main body 602 and the various components mounted on the opening / closing housing 606 are maintained in a positional relationship indicated by the solid line) and a two-dot chain line. It is pivotable between the indicated open position (in which the process unit 608 can be detached from the opening / closing housing 606).

An optical unit 610 is provided in the lower main body 603.
Is installed. On the bottom wall 612 of the device main body 602,
In FIG. 16, a pair of mounting walls 614 and 616 are provided at intervals in the left-right direction. At both ends of the mounting walls 614 and 616, respectively, the contact protrusions 61 protruding inward.
8 and 620 (only one of them is shown in FIG. 16), and the upper ends of the mounting walls 614 and 616 are provided with upper contact projections 622 and 624 projecting inward. The optical unit 610 is mounted between a pair of mounting walls 614 and 616. The optical unit 610 is movable in the left-right direction in FIG. 16 from a position in contact with one of the mounting walls 614 to a position in contact with the other mounting wall 616, and one of the mounting projections 618 of the mounting walls 614 and 616. 16 and 620 to a position abutting on the other abutting projections 618 and 620 in a direction perpendicular to the plane of FIG. Also, as understood from FIG. 16, the optical unit 610 moves the mounting wall 61 from a position where it contacts the bottom wall 612 of the apparatus main body 602.
4 and 616 can also be moved up and down to positions where they contact the upper contact protrusions 622 and 624. In the fourth embodiment, a plurality of bias coil springs 628 are further interposed between the bottom wall 612 and the optical unit frame 626 of the optical unit 610. These biasing coil springs 628 elastically bias the optical unit frame 626 upward.

The process unit 608 is detachably mounted on the opening / closing housing 606. Openable housing 6
In FIG. 16, support rails 630 and 632 are arranged at intervals in the left-right direction in FIG. One of the support rails 630 has an L-shaped cross section, and
6 cooperates with a guide plate 634 mounted on the guide plate 6 to define a guide groove. The other support rail 632 has a rectangular cross section, and a guide groove is defined on one side (the right side in FIG. 16). On the other hand, the process unit 608 includes a process unit frame 634.
In FIG. 16, the supported projections 636 and 6 corresponding to the support rails 630 and 632 are provided at both ends in the left-right direction.
38 are provided.

Further, three circular projections 640 (two of them are shown in FIG. 16) are provided on the upper wall of the optical unit frame 626, and these circular projections 640 have circular receiving holes. Is stipulated. Also, the process unit frame 6
Pins 642 are provided on the bottom wall of the bottom plate 34 so as to correspond to the circular receiving holes, and the tips of the pins 642 are tapered. One pin 642 and the receiving hole of the circular projection 640 for receiving the pin 642 function as positioning means, and the other
The pins 642 and the receiving holes of the circular projections 640 for receiving these pins function as rotation preventing means.
2 is a process unit frame 634 and an optical unit frame 626
Function as a functioning piece for keeping the distance between them constant. 4th
The other basic configuration in this embodiment is substantially the same as that in the first embodiment.

In the fourth embodiment, the process unit 6
In order to detachably attach 08 to the apparatus main body 602, the open / close housing 606 is turned in the direction indicated by the arrow 644 to the open position indicated by the two-dot chain line. Then, the supported protrusions 636 and 638 of the process unit frame 634 are positioned in the guide grooves of the support rails 630 and 632, and the process unit frame 634 is moved along the guide grooves in a direction perpendicular to the plane of FIG. Let me move. Thereafter, the open / close housing 606 with the process unit 608 mounted is moved from the open position to the closed position. Thus, as shown in FIG. 16, the pins 642 provided on the process unit frame 634 are removably received in the corresponding holes of the circular projection 640, and thus the process unit 608 and the optical unit 610
The positional relationship shown in the figure is maintained. That is, the optical unit 610 is movable in a horizontal direction over a predetermined range as in the first embodiment, but when the open / close housing 606 is set to the closed position, the pins 642 correspond to the corresponding circular protrusions 640.
Of the optical unit 61
The specific part of the process unit 608 and the specific part of the process unit 608 are aligned with each other in the vertical direction, and their relative rotation is also prevented. Thus, the optical unit 610 and the process unit 608 function as positioning means and rotation preventing means. It is directly held in a predetermined positional relationship via the pin 642 and the receiving hole of the projection 640. Further, the distal end surface of each pin 642 abuts on a portion of the circular projection 640 that defines the bottom surface of the receiving hole, and the optical unit 610 is lowered somewhat against the biasing force of the biasing coil spring 628. Accordingly, the optical unit 610 is provided via the pin 642 functioning as a working piece.
Is pressed by the process unit 608, and the vertical distance between the optical unit 610 and the process unit 608 is set sufficiently sufficiently.

[0052]

According to the image forming apparatus of the present invention, the relative positions of the image carrying means and the optical unit in the directions approaching and separating from each other are set sufficiently accurately by relatively simple and inexpensive means. In addition, the relative positions of the image bearing means and the optical unit in the directions approaching and separating from each other are set sufficiently accurately by relatively simple and inexpensive means, and the relative positions in the directions approaching and separating from each other are sufficiently high. Thus, the relative position in the substantially vertical direction is set sufficiently accurately.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a first embodiment of a laser beam printer as an example of an image forming apparatus configured according to the present invention.

FIG. 2 is a front view showing the laser beam printer of FIG.

FIG. 3 is a simplified cross-sectional view of the laser beam printer of FIG.

FIG. 4 is a sectional view showing an optical unit and its vicinity in the laser beam printer of FIG. 1;

FIG. 5 is a plan view showing an optical unit in the laser beam printer of FIG.

FIG. 6 is a sectional view for explaining a positional relationship between an optical unit and a process unit in the laser beam printer of FIG.

FIG. 7 is a sectional view showing a process unit and its vicinity in the laser beam printer of FIG. 1;

FIG. 8 is a simplified diagram for explaining a mounting mode of the process unit in FIG. 7;

FIG. 9 is a simplified diagram showing a part of a drive system in the laser beam printer of FIG.

10 is a sectional view showing the electric motor of the drive system shown in FIG. 9 and its vicinity.

FIG. 11 is a simplified cross-sectional view showing a process unit, an optical unit, and their vicinity in a second embodiment of a laser beam printer as an example of an image forming apparatus according to the present invention.

FIG. 12 is a plan view for explaining a mounting mode of a process unit in the laser beam printer of FIG. 11;

FIG. 13 is a sectional view for explaining a positional relationship between an optical unit and a process unit in the laser beam printer of FIG.

FIG. 14 is a partial cross-sectional view showing a state in which a receiving portion defined on the projection of the unit frame and the projection of the optical unit frame in the laser beam printer of FIG. 11 are engaged.

FIG. 15 is a simplified cross-sectional view showing a process unit, an optical unit, and their vicinity in a third embodiment of a laser beam printer as an example of an image forming apparatus according to the present invention.

FIG. 16 is a simplified sectional view showing a fourth embodiment of a laser beam printer as an example of an image forming apparatus according to the present invention.

[Explanation of symbols]

2, 418, 510 and 602... Device main body 6 and 603... Lower body portion 4 and 606. Housings 36, 402, 502 and 608 ... Process units 38, 404, 504 and 634 ... Process unit frames 40 and 410 ... Rotating drum 46 ... ····· Developing devices 56, 420, 518 and 610 ··· Optical unit 69 ····· Optical means 120 434, 520, and 626: Optical unit frame 156, 444, 532, and 628: biasing coil spring 222 and 224: receiving hole 226: ..... Positioning pin 228 ... ... Rotation prevention pins 230, 448, and 540 ... Working pieces 436 and 522 ... Protrusion 642 ... ············pin

Continuation of the front page (72) Inventor Katsushi Horihata 1-2-2, Tamazo, Chuo-ku, Osaka City Inside Mita Kogyo Co., Ltd. (72) Inventor Hiroyuki Tanaka 1-2-28, Tamazo, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (56) References JP-A-59-59067 (JP, A) JP-A-61-116562 (JP, A) JP-A-61-97663 (JP, A) JP-A-61-143117 (JP, U) Kaisho 62-38166 (JP, U)

Claims (10)

(57) [Claims] 1. A comprising an image bearing means having a photosensitive member mounted on and surfaces in a frame, the light having image information and an optical unit for projecting on the photosensitive body of the image bearing means, said optical unit Is mounted movably over a predetermined range in a direction to approach and separate from the frame, and one of the optical unit and the frame is attached to the other.
The three working pieces that are projected
Ri, resiliently biased allowed towards the optical unit to the frame,
An image forming apparatus, comprising: a biasing unit that presses the optical unit against the frame via the three action pieces . Wherein the frame is a process unit frame, the process unit frame and the image bearing means mounted thereto constitutes a process unit detachably attached to the apparatus main body, according to claim 1, wherein Image forming device. 3. The apparatus main body includes a lower main body and an opening / closing housing pivotally mounted on the lower main body between an open position and a closed position, and the process unit is mounted on the lower main body. The optical unit is mounted on the open / close housing, and when the open / close housing is moved to the closed position, the biasing means presses the optical unit against the process unit via the three working pieces. Item 3. The image forming apparatus according to Item 2 . 4. Both ends of the process unit are attached to the lower main body via a pair of support means, and one of the pair of support means rotatably supports one end of the process unit. 4. The image forming apparatus according to claim 3 , wherein the other of said supporting means acts on the other end of said process unit to prevent a pivoting movement beyond a predetermined position. 5. The optical unit moves closer to the frame.
Positioning means for movably mounted over a predetermined range in an arbitrary direction substantially perpendicular to the separating direction, and for substantially matching a specific portion of the frame with a specific portion of the optical unit; The image according to any one of claims 1 to 4 , wherein a rotation preventing means for preventing relative rotation between the frame and the optical unit around the specific portion is provided. Forming equipment. Wherein said positioning means is constituted by the positioning receiving portions provided on the other of the positioning protrusion and the frame and the optical unit provided on one of the said frame and the optical unit,該回The movement preventing means comprises a rotation preventing protrusion provided on one of the frame and the optical unit, and a rotation preventing receiving portion provided on the other of the frame and the optical unit. Item 6. The image forming apparatus according to Item 5 . 7. The positioning projection is formed of a cylindrical positioning pin, the positioning receiving portion is formed of a circular receiving hole having an inner diameter corresponding to the outer diameter of the positioning pin, and the rotation preventing projection is formed of a cylindrical shape. The image forming apparatus according to claim 6 , wherein the rotation prevention pin is formed of an elongated receiving hole having a width corresponding to an outer diameter of the rotation prevention pin. 8. A photoreceptor mounted on a frame and having a photoreceptor on a surface.
Image carrying means, and light having image information
An optical unit for projecting onto the photoreceptor, wherein the optical unit moves in a direction approaching and away from the frame.
Moveable over a predetermined range, and approaching and separating
Over a range in any direction substantially perpendicular to the direction
Are freely mounted mobile Te, to one of the optical unit and the frame is directed to the other
One that has a polygonal external shape
And the other of the optical unit and the frame has an inner shape outside the protrusion.
A polygonal shape corresponding to the shape, one to receive the protrusion
Is provided, and the optical unit is elastically biased toward the frame,
Through the projection and the receiving portion in which the projection is received,
Biasing means for pressing the unit against the frame is provided;
That, the image forming apparatus characterized by. 9. The frame has a rectangular portion that defines an exposure opening for guiding light from the optical unit to the image carrier. The optical unit includes an optical unit frame,
The optical unit frame is formed a rectangular-shaped portion which defines the projection opening, one with sites該矩shape defining a site and the projection opening of該矩shape defining an aperture for the exposure
The other constituting the receiving portion, and the other constituting the projection.
9. The image forming apparatus according to 8 . 10. One of the optical unit and the frame includes:
One working piece projecting toward the other is provided
Wherein the biasing means comprises the projection and the
Through the receiving part and also through the working piece
10. The science unit is pressed against the frame.
Image forming apparatus.