JPH09222838A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately position and fix a process unit in a device main body by supporting a side surface member arranged on the device front side of the process unit with plural support members. SOLUTION: A process unit side plate 21 of a process unit 4 also serves as a positioning face plate, and the process unit 4 is inserted from an opening part 43 of a device main body 100, and is pushed in the arrow A direction until end parts 21a and 21b of the process unit side plate 21 come into contact with support members 18 and 19 on the device main body side. Then, positioning holes 22a and 22b formed in the end parts 21a and 21b of the process unit side plate 21 and positioning pins 23a and 23b formed on the support members 18 and 19 of the device main body 100, respectively engage with each other, and the process unit 4 is positioned in the device main body 100. Therefore, positional accuracy is improved, and the occurrence of a convergence error and jitter can be prevented as much as possible. Operability at replacing time is also improved.

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 copying machine, a facsimile, and a printer.
The present invention relates to an image forming apparatus including a plurality of image forming units.

[0002]

2. Description of the Related Art Conventionally, there is known a multicolor or multicolor image forming apparatus in which a plurality of image forming units are linearly arranged and a transfer belt is electrostatically adsorbed and conveyed. In such an image forming apparatus, an image forming unit (hereinafter referred to as a process unit) is unitized for each color in order to improve operability when the unit is replaced, and when replacing, the front side (front side) of the apparatus is replaced. The structure is such that it can be pulled out. For this reason, in the conventional image forming apparatus, a large opening is opened in the front side plate of the apparatus body, and the process unit is shown in FIG.
As shown in FIG. 5, it is supported by one positioning face plate 52 provided at both ends of the opening portion 51, or as shown in FIG.
Alternatively, as shown in FIG. 6C, the positioning face plate 56 is individually provided between the supporting members 55 formed in a comb-teeth shape so as to be supported. In FIG. 12, reference numeral 53 indicates a photosensitive drum in the process unit.

[0003]

However, FIG.
In (a), since there is only one positioning face plate, operability is poor. In (b), one side is supported, and in (c), the comb-teeth shaped portion is weak in strength. Support was unstable. That is, in the conventional support structure, the weight balance of the unit collapses, so that the positional accuracy deteriorates, which causes color misregistration. Also,
Since the strength is weak, there is a problem that jitter is likely to occur. Particularly, in the method of fixing to the side plate between the process units as shown in FIG. 12 (c), a space for fixing is required, so that the interval between the process units becomes large and it is difficult to downsize the apparatus. Met.

On the other hand, as a means for solving such problems, for example, Japanese Patent Laid-Open No. 62-229264 proposes a method of providing a support member (face plate) for integrally supporting each unit and the main body. However, in this method, when one process unit is attached or detached, the other process units also come off from the main body, so that there is a problem that operability is poor. In addition, since other process units are not supported by the apparatus during the replacement work, the accuracy may be deteriorated.

The present invention has been made in view of the above problems, and an object thereof is to enable the process unit to be positioned and fixed to the apparatus main body with high accuracy and also to be easy to replace. An excellent image forming apparatus is provided.

[0006]

In order to achieve the above object, the invention of claim 1 is such that a plurality of image forming units are detachably mounted between at least two supporting members arranged on the front side of the apparatus. In the image forming apparatus described above, the side member disposed on the front side of the image forming unit is supported by the at least two supporting members.

According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, engaging means for engaging the side member of the image forming unit and the at least two supporting members at predetermined positions is provided. To do.

According to a third aspect of the present invention, in the image forming apparatus according to the first aspect, there is provided an engaging means for engaging a side member disposed on the rear side of the image forming unit with the main body of the apparatus at a predetermined position. It is characterized by being provided.

According to a fourth aspect of the present invention, in the image forming apparatus according to the second or third aspect, the engaging means includes a positioning hole and a positioning pin.

Here, among the positioning pins, the positioning pin used in the image forming apparatus of the third aspect may be formed with a tapered portion for guiding the tip of the positioning pin to the positioning hole. In this case, the taper angle (θ) of the tapered portion is preferably 4 ° to 17 ° so that the pin tip can be easily guided into the hole. Further, the ratio of the diameter (D) of the pin to the length (L) of the tapered portion 29a at this time is preferably D: L = 1: 1.5 to 1: 4.

According to a fifth aspect of the present invention, in the image forming apparatus according to the first aspect, fixing means for detachably fixing the image forming unit to the apparatus main body is provided.

According to a sixth aspect of the present invention, in the image forming apparatus according to the first aspect, guide means for supporting the image forming unit and for guiding the unit in the attaching / detaching direction is provided.

According to the present invention, the side member of the image forming unit mounted on the apparatus main body is stably supported between at least two supporting members.

Particularly, in the second aspect of the invention, the image forming unit and at least two supporting members are supported by the engaging means in a state of being engaged at a predetermined position.

Further, particularly in the invention of claim 3,
The side member disposed on the back side of the image forming unit is
It is supported by the engaging means in an engaged state at a predetermined position.

Particularly, in the invention of claim 4, the side surface member and the supporting member, and the side surface member and the apparatus main body are supported by the engagement of the positioning hole and the positioning pin.

Further, particularly in the invention of claim 5,
The image forming unit mounted on the apparatus body is fixed to the apparatus body side by the fixing means, and the fixing by the fixing means can be released.

Particularly, in the invention of claim 6, when the image forming unit is mounted on the apparatus main body, the image forming unit is guided to the mounting position while being guided by the guide means, and after being mounted on the apparatus main body. The unit is supported by guide means.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to an electrophotographic copying machine (hereinafter referred to as a copying machine) which is an image forming apparatus will be described below. FIG. 2 is a schematic configuration diagram of the copying machine according to the present embodiment. First, copy machine 10
The overall operation of 0 will be described. In the following description, the copying machine 100 will be referred to as “apparatus body 100” as appropriate.
That. First, the recording paper (not shown) fed from the paper feeding unit 1 is adjusted to the lateral position by the lateral registration unit 2 and then conveyed to the leading edge registration sensor 3.
Then, when the light passes through the leading edge registration sensor 3, image data is written by the optical writing unit 5 at this timing, and each process unit 4 starts image formation. On the other hand, the recording paper is electrostatically attracted and conveyed by the transfer belt 6, and when passing through each process unit 4, the transfer roller 7 transfers images one after another. After that, the recording paper separated from the transfer belt 6 by the separation charger 8 is
The image is fixed by the heat and pressure of the fixing unit 9, and is conveyed to the paper discharge unit 14 by the conveying unit 10. The switching guide plate 11 of the paper discharge unit 14 is the paper discharge tray 12.
When the recording sheet is displaced to the side, the recording sheet is discharged to the discharge tray 12. Further, when the recording paper is displaced to the side of the duplex unit 13, several sheets of recording paper are stacked by the duplex unit 13 and then fed to the process unit again.

[Embodiment 1] FIG. 1 is a conceptual perspective view showing the structure of a connecting portion between a process unit and an apparatus main body, and shows the structure of the first embodiment. Although two process units are shown in FIG. 1, actually four process units are linearly arranged as shown in FIG. In FIG. 1, on the front side of the apparatus main body 100,
The support member 41 is provided at a position substantially parallel to the transfer belt 6 of FIG.
And 42 are provided. A substantially comb-shaped opening 43 is formed between the two support members, and each process unit 4 is configured to be detachable in the opening 43. The opening 43 may be formed between two or more support members. The process unit 4 includes the process unit side plate 21, the photoconductor drum 20,
It is composed of a cleaning unit 24 and a developing tank / driving unit 25.

The process unit side plate 21 of the process unit 4 also serves as a positioning face plate, and when the process unit 4 is mounted on the apparatus main body 100, the end portions 21a and 21b which come into contact with the supporting members 14 and 42 on the apparatus main body side are provided. Has been formed. Positioning holes 22a and 22b are formed in both ends 21a and 21b, respectively. On the other hand, on the support members 41 and 42, the positioning pin 23 is provided at a predetermined position corresponding to the positioning holes 22a and 22b.
a and 23b are provided. This positioning hole 22a,
22b and the positioning pins 23a and 23b function as an engaging means for engaging the process unit side plate 21 and the supporting members 41 and 42 at predetermined positions.

In FIG. 1, the process unit 4 is inserted from the opening 43 of the apparatus main body 100, and the end portions 21a and 21b of the process unit side plate 21 are supported by the support members 41 and 42.
When pushed in the direction of arrow A until it comes into contact with, the positioning holes 22a and 22b formed in the end portions 21a and 21b of the process unit side plate 21 and the positioning pins 23a and 23b formed in the support members 41 and 42 are engaged with each other. Then, the process unit 4 is positioned on the apparatus main body 100.
In FIG. 2, the process unit before mounting is shown in the lower stage, and the process unit after mounting is shown in the upper stage.

According to the copying machine configured as described above,
When the process unit 4 is attached to the apparatus main body 100, both end portions 21a and 21b of the unit are supported by the support members 41 and 42.
Since it is supported by the apparatus main body 100 at two places, it is possible to support the unit more stably than when it is supported on one side of the unit or at a weaker portion. Therefore, the positional accuracy is improved, and the occurrence of color misregistration and jitter can be prevented as much as possible. Further, since the process unit side plate 21 also serves as the positioning face plate, the positioning face plate can be omitted. Further, when one process unit is attached or detached, the other process unit does not come off from the main body of the apparatus, so that the accuracy is not deteriorated and the operability at the time of replacement is excellent. Moreover, since a special space for fixing the unit is not required, it is possible to reduce the size of the apparatus without increasing the space between the process units. Further, since the process unit side plate 21 and the supporting members 41 and 42 are supported by the engagement of the positioning holes and the positioning pins, highly accurate positioning can be performed with a simple configuration.

In the first embodiment, the process unit side plate 21 is provided with positioning holes 22a and 22b, and the supporting member 4 is provided.
Although the positioning pins 23a and 23b are provided on the Nos. 1 and 42, the positioning pins 23a and 23b are provided on the process unit side plate 21.
23b, and the positioning holes 22 are formed in the support members 41 and 42.
Even if a and 22 are provided, the same effect can be obtained. Further, the positions of the positioning holes 22a and 22b and the positioning pins 23a and 23b as the engaging means are common to all colors, but may be changed for each color. When the position of the engaging means is changed for each color, it is possible to prevent a mistake in mounting the process unit in a different color position.

[Embodiment 2] FIG. 3 is a conceptual perspective view of the structure of the connecting portion between the process unit and the apparatus main body, and shows the structure of the second embodiment. Further, the same parts as those in FIG. 1 are designated by the same reference numerals. Originally, the process unit has an unbalanced shape as shown in the figure, and the entire unit is in a state of tilting toward the photosensitive drum 20 side. Therefore, when the process unit 4 of FIG. 1 is inserted into the apparatus main body 100, the positioning holes 22a and 22b are provided.
Must be mounted while lifting the photosensitive drum 20 side of the process unit 14 so that can be smoothly engaged with the positioning pins 23a and 23b. Similarly, when the process unit is removed, the photosensitive drum side must be lifted and mounted in order to avoid interference with the support member 41 having the positioning pin 23b and the transfer unit (not shown). . Therefore, the copying machine according to the second embodiment is provided with a guide member that supports the process unit 14 and guides the unit in the attachment / detachment direction. This guide member includes two guide rails 2 arranged above and below.
6 and 27. As shown in FIG.
One guide rail 26 constituting the guide member is arranged above the cleaning unit 24, and the other guide rail 27 constituting the guide member is arranged on the photosensitive drum 20.
It is arranged on a base (not shown) provided in the lower part of the.
The guide rail 26 arranged at the upper part is formed to have a substantially concave cross section, and the guide rail 27 arranged at the lower part is formed to have a substantially convex cross section. Further, the upper and lower guide rails are arranged at positions that match each other in plan view, and when the process unit 14 is mounted on the apparatus main body 100, the upper and lower guide rails are fitted to each other.

In FIG. 3, when the process unit 14 is mounted on the apparatus main body 100, the process unit 14
The guide rails 26 arranged in the upper part of the process unit 14 are fitted to the guide rails 27 in the lower part of the process unit mounted in the upper stage, and the guide rails 27 arranged in the lower part of the process unit 14 are mounted in the lower stage. It is fitted to the guide rail 26 above the process unit (not shown). Then, when the process unit 14 is pushed in the direction of arrow A in this state, the process unit 14 is provided with a guide rail 27 arranged at the lower part and a diagram arranged on the upper part of a process unit (not shown) mounted on the lower stage. Since it is supported by a guide rail (not shown), it can be mounted without lifting the photoconductor drum 20 side. At the same time, the process unit 14 is guided into the apparatus main body 100 while being guided by the guide rails, so that the unit can be attached and detached more quickly.

According to the copying machine configured as described above,
When the process unit 14 is attached to the apparatus main body 100,
Since the process unit 14 is supported by the guide rails of the process unit (not shown) mounted on the lower stage, the process unit 14 can be mounted without lifting the photosensitive drum 20 side. Moreover, since the process unit 14 is guided into the apparatus main body 100 while being guided by the guide rails,
The unit can be attached and detached more quickly, and the operability can be greatly improved.

In the second embodiment, the guide rail 26 having a substantially concave cross section is arranged at the upper part of the process unit 14 and the guide rail 27 having a substantially convex cross section is arranged at the lower part. The same effect can be obtained by disposing the guide rail 27 having a substantially convex cross section at the upper part of the unit 14 and disposing the guide rail 26 having a substantially concave cross section at the lower part. Further, the cross-sectional shape of the guide rail is not limited to this embodiment, and any other shape can be used as long as it is a shape that restricts the movement in the lateral direction. Further, although the upper and lower guide rails are arranged so as to coincide with each other in plan view, they may be arranged at different positions for each process unit 14. In this way, when the position of the guide member is changed for each color, it is possible to prevent a mistake in mounting the process unit at a position of a different color.

[Third Embodiment] Next, an embodiment in which a fixing means for detachably fixing the process unit 4 to the apparatus main body 100 is provided will be described. FIG.
(A)-(c) is a schematic sectional drawing which shows the structure of the positioning pin which provided the fixing means. First, the structure of the positioning pin will be described with reference to FIG. The positioning pin 41 shown in FIG. 4 is a pin corresponding to the positioning pins 23a and 23b in FIG.

In FIG. 4A, the main body of the positioning pin 41 is formed in a substantially cylindrical shape, and one end thereof is fixed to the front plate 40 of the main body of the apparatus (corresponding to the supporting members 41 and 42 in FIG. 1). Has been done. At one end of the positioning pin 41,
Slide pin 42 movably supported in the horizontal direction in the figure
Are arranged. A head portion 42a and a taper portion 42b are formed on the slide pin 42 and are normally urged to the left side in the figure by the elastic force of a spring spring 44. On the other hand, at the other end of the positioning pin 41, a lock claw 43 rotatably supported about a shaft 46 is provided. The front end 43a of the lock claw 43 abuts on the tapered portion 42b of the slide pin 42, and the rear end 43b is biased upward by the elastic force of the spring spring 45. Further, an oblique side 43c that restricts the movement of the process unit side plate 21 is formed above the lock claw 43. The slide pin 42 and the lock claw 43 as the fixing means are always stopped at the illustrated fixed positions.

Next, the operation of the positioning pin 41 when the process unit 4 of FIG. 1 is mounted on the apparatus main body 100 will be described with reference to FIGS. 4 (a) to 4 (c). The reference numerals in parentheses indicate the reference numerals of FIG. 1 which are not shown in FIG. When the process unit (4) is attached to the apparatus main body (100), the process unit side plate 21 begins to move in the direction of arrow A in the figure and is positioned in the positioning hole 22 of the process unit side plate 21 as shown in FIG. The pin 41 enters. Then, when the process unit side plate 21 reaches the position of the lock claw 43, the oblique side 43 c of the lock claw 43 is pushed downward by the side edge of the positioning hole 22. Then, as shown in FIG. 4B, the lock claw 43 rotates clockwise around the shaft 46 against the elastic force of the spring spring 45 and retracts inside the pin. After that, when the process unit side plate 21 passes over the retracted lock claw 43, the oblique side 43c is pushed upward by the elastic force of the spring spring 45, as shown in FIG.
The lock claw 43 rotates counterclockwise about the shaft 46 and returns to the fixed position again. Therefore, even if the force that moves the process unit (4) to the left side of the drawing acts in the state of FIG. 4C, the side edge of the positioning hole 22 of the process unit side plate 21 collides with the hypotenuse 43c of the lock claw 43. Since the movement of the process unit side plate 21 is restricted, the process unit side plate 21 cannot be pulled out from the positioning pin 41. Therefore, the process unit (4) is engaged and fixed to the apparatus main body front side plate 40.

Next, the operation of the positioning pin 41 when the process unit 4 of FIG. 1 is removed from the apparatus main body 100 will be described with reference to FIG. When removing the process unit (4) from the apparatus body (100), the head portion 42a of the slide pin 42 is attached to the spring spring 44 as shown in FIG.
Push in the direction of arrow A against the elastic force of. Then, the end 43a of the lock claw 43 is pushed upward with the movement of the tapered portion 42b, so that the lock claw 43 rotates clockwise about the shaft 46 against the elastic force of the spring spring 45, and the inside of the pin is rotated. Evacuate to. In this state, since the side edge of the positioning hole 22 of the process unit side plate 21 does not interfere with the oblique side 43c of the lock claw 43, the process unit side plate 21 can be pulled out from the positioning pin 41. Therefore, the process unit (4) is installed in the apparatus main body (10
0) can be easily removed.

According to the copying machine configured as described above,
The process unit side plate 21 is positioned and fixed to the device body front side plate 40 only by mounting the process unit (4) on the device body (100). When the head portion 42a of the positioning pin 41 is pushed in, the process unit side plate 2
The engagement between 1 and the front plate 40 of the apparatus main body is released, and the process unit (4) can be removed from the apparatus main body (100). As described above, in the copying machine according to the third embodiment, the process unit (4) is automatically fixed, and the fixed state can be arbitrarily released, which is excellent in operability. Moreover, when mounting the process unit (4),
The unit can be securely fixed to the device body.

[Embodiment 4] FIG. 6 is a conceptual perspective view of a process unit in Embodiment 4, and the same parts as those in FIG. 1 are designated by the same reference numerals. Although FIG. 6 shows the state when the unit is viewed from the back side, the cleaning unit 24 and the photoconductor drum 20 are shown for the sake of clarity.
Is omitted. In FIG. 6, the process unit 15
A process unit back side plate 28 that comes into contact with a device body back side plate to be described later is disposed on the back side (front side in the drawing). This process unit back side plate 28 is attached to one end of a drive base 30 which is also disposed at the back side of the unit, and has two unit positioning pins 29 on the outside.
Are arranged at predetermined intervals. Also, the drive base 3
The end portion 30a of 0 is bent as shown in the drawing, and the drive gear side plate 3 that supports the drive gear 32 is provided below this portion.
4 is attached. The drive gear side plate 34 includes
A gear positioning pin 33 for positioning with a drive gear in a device body (not shown) is provided. Also,
Reference numeral 31 indicates a developing tank.

FIG. 7 is a partially enlarged view showing the shape of the unit positioning pin 29. The unit positioning pin 29 is formed with a taper portion 29a for guiding the pin into a positioning hole formed in a back plate of the apparatus body which will be described later. The taper angle (θ) of the taper portion 29a is preferably 4 ° to 17 ° so that the pin tip can be easily guided into the hole. The ratio of the pin diameter (D) to the length (L) of the tapered portion 29a at this time is D: L = 1:
It is preferably 1.5 to 1: 4. Also, the gear positioning pin 3
A similar taper portion is also formed on 3. FIG. 8 is a schematic side view when the process unit 15 is viewed from the direction of arrow A in FIG. Since the end portion 30a of the drive base 30 bends to some extent at the bent portion, the position of the gear positioning pin 33 arranged on the drive gear side plate 34 can be vertically displaced. (Hereinafter, margin)

FIG. 9 is a partial plan view as seen from the direction of arrow B in FIG. 6, showing the relationship between the unit positioning pin 29 and the gear positioning pin 33. Further, reference numeral 35 in the figure denotes a plate on the inner side of the apparatus main body disposed inside the copying machine. FIG.
As shown in, the length of the unit positioning pin 29 (x
1) is set to be longer than the length (x2) of the gear positioning pin 33, and the diameter (D) of the unit positioning pin 29.
Is set to be larger than the diameter (d) of the gear positioning pin 33.

In FIG. 9, when the process unit 15 is moved in the direction of arrow A in the figure, the unit positioning pin 29 first comes into the positioning hole 36 formed in the back plate 35 of the apparatus main body and further moves. Then, the gear positioning pin 33 starts to enter the positioning hole 37. And
When the process unit back side plate 28 is pushed in the direction of arrow A until it comes into contact with the apparatus body back side plate 35, the unit positioning pin 29, the positioning hole 36, and the gear positioning pin 33.
And the positioning hole 37 are all engaged, and the process unit 1
5 is positioned inside the apparatus main body. At this time, the two unit positioning pins 29 that have entered the positioning holes 36.
The process unit 15 is roughly positioned by the gear positioning pin 33 in this state.
The gear positioning pin 33 to the positioning hole 3
Can be accurately guided to 7. Further, since the unit positioning pin 29 and the gear positioning pin 33 are formed with the tapered portions, the tips of the pins can be easily inserted into the respective positioning holes. Especially positioning pin 33
As shown in FIG. 8, since the position of is movably up and down, even if the positions of the positioning pin 33 and the positioning hole 37 are slightly deviated, even if the tip of the pin enters the hole, Then, as the positioning pin 33 enters the positioning hole 37, the end portion 30a of the drive base 30 bends, and the positioning pin 33 is guided into the positioning hole 37. As described above, the dimensional error generated between the unit positioning pin 29 and the gear positioning pin 33 is absorbed by the bending of the end portion 30a of the drive base 30, so that the positioning pin 33 to be inserted later can be easily positioned. You can

According to the copying machine configured as described above,
Since the gear positioning pin 33 is guided to the positioning hole 37 while the unit positioning pin 29 is roughly positioned, the gear positioning pin 33 can be accurately guided to the positioning hole 37. Further, since the tapered portion is formed at the tip of each pin, the pin can be easily inserted into the hole. Further, since the positioning pin 33 is configured to bend to some extent, the positioning pin 33 can be easily positioned without being affected by a dimensional error.
Therefore, operability is good, and highly accurate positioning is possible.

[Fifth Embodiment] FIG. 10 shows the structure of a process unit according to the fifth embodiment, and is a partial plan view of the unit as in FIG. In the fourth embodiment, the unit positioning pins 29 and the like are arranged on the process unit back side plate 28 side, and the positioning holes 36 and the like are formed in the apparatus main body back side plate 35. However, in the fifth embodiment, the process unit back side plate is formed. A positioning hole 38 is formed on the 28 side, a positioning hole 39 is formed on the gear drive side plate 34, and a unit positioning pin 29 and a gear positioning pin 33 are arranged on the device body inner side plate 35. Since the other configurations are the same as those of the fourth embodiment, the description thereof will be omitted.

In FIG. 10, when the process unit 16 is moved in the direction of arrow A in the figure, the positioning hole 38 is first formed.
When it starts to enter into the unit positioning pin 29 and further moves, the gear positioning pin 3 is then inserted into the positioning hole 39.
Start to enter 3. Then, the process unit back side plate 28
Is pushed in the direction of arrow A until it comes into contact with the back plate 35 of the apparatus body, the unit positioning pin 29 and the positioning hole 38,
Also, the gear positioning pin 33 and the positioning hole 39 are all engaged, and the process unit 16 is positioned inside the apparatus main body. At this time, the two unit positioning pins 29 that have entered the positioning holes 38 are used to process the process unit 16
Since the positioning hole 39 is guided to the gear positioning pin 33 in this state, the positioning hole 39 can be accurately guided to the gear positioning pin 33. Further, since the unit positioning pin 29 and the gear positioning pin 33 are formed with the tapered portions, the tips of the pins can be easily inserted into the respective positioning holes. Particularly, since the position of the positioning hole 39 is configured to be vertically displaceable as in the third embodiment,
Even if the positions of the positioning hole 39 and the positioning pin 33 are slightly deviated, as long as the pin tip is in the hole, as the positioning pin 33 moves into the positioning hole 39, the drive base (not shown) as in the third embodiment. The end portion 30a of 30 is bent, and the positioning hole 39 is guided into the gear positioning pin 33. As described above, the dimensional error of the gear positioning pin 33 with respect to the unit positioning pin 29 is absorbed by the bending of the end portion 30a of the drive base 30.
The positioning pin 33 to be inserted later can be easily positioned.

FIG. 11 is a conceptual cross-sectional view showing an essential state of the unit positioning pin and the positioning hole. FIG.
(A) shows the engagement state of Embodiment 4 as a comparative example,
FIG. 3B shows the engagement state in this embodiment. As shown in FIG. 11A, the process unit back side plate 28
If the unit positioning pin 29 is installed in
Depending on the weight (W) of the process unit, the mounting portion of the process unit back side plate 28 may bend as shown by the broken line in the figure. On the other hand, as shown in FIG. 11B, when the unit positioning pin 29 is provided on the back plate 35 of the apparatus body, the weight (W) of the process unit is set.
Even if the process is applied, the process unit back side plate 28 hardly bends because the rigidity of the apparatus main body back side plate 35 is high.

According to the copying machine configured as described above,
Since the gear positioning pin 33 is guided to the positioning hole 39 in a state where the unit positioning pin 29 is roughly positioned, the gear positioning pin 33 can be accurately guided into the positioning hole 39. Further, since the tapered portion is formed at the tip of each pin, the pin can be easily inserted into the hole. Further, since the positioning hole 39 is configured to bend to some extent, it can be easily positioned without being affected by dimensional error. In addition, since the unit positioning pin 29 and the gear positioning pin 33 are provided on the back plate 35 of the apparatus main body, the process unit back plate 28 does not bend due to the weight of the process unit, which enables more accurate positioning. Become.

[0043]

According to the present invention, since the side surface member of the image forming unit mounted on the apparatus main body is stably supported between at least two supporting members, it is supported on one side of the unit. Alternatively, it is possible to improve the positional accuracy as compared with the case where it is supported at a weaker portion. Therefore,
Since the unit is positioned and fixed with high accuracy, it is possible to prevent color misregistration and jitter from occurring as much as possible. Further, when one image forming unit is attached or detached, the other image forming units do not come off from the apparatus main body, so that the accuracy is not deteriorated and the operability at the time of replacement is excellent.

In particular, according to the second aspect of the invention, since the image forming unit and the at least two supporting members are supported by the engaging means in a state of being engaged at a predetermined position, highly accurate positioning is possible. .

According to the third aspect of the invention, since the side member disposed on the rear side of the apparatus of the image forming unit is supported in a state of being engaged at a predetermined position by the engaging means, it is possible to enhance the height. Accurate positioning is possible.

In particular, according to the invention of claim 4, since the side surface member and the supporting member, and the side surface member and the apparatus main body are supported by the engagement of the positioning hole and the positioning pin, the positioning can be performed with high precision with a simple structure. It will be possible.

Further, according to the invention of claim 5, the image forming unit is detachably fixed to the apparatus main body by the fixing means, so that the image forming unit mounted on the apparatus main body is surely fixed. You can Further, since the fixing by the fixing means can be released, the image forming unit can be appropriately removed from the apparatus main body.

In particular, according to the invention of claim 6, when the image forming unit is mounted on the apparatus main body, the unit is guided to the mounting position while being guided by the guide means, and after the unit is mounted on the apparatus main body. Since the unit is supported by the guide means, the unit can be attached and detached more quickly, and the operability can be greatly improved.

[Brief description of drawings]

FIG. 1 is a conceptual perspective view of a main part showing a configuration of a first embodiment.

FIG. 2 is a schematic configuration diagram of a copying machine according to the embodiment.

FIG. 3 is a principal perspective view showing the configuration of the second embodiment.

4A to 4C are schematic cross-sectional views showing the configuration of the third embodiment.

FIG. 5 is a schematic cross-sectional view showing the configuration of the third embodiment.

FIG. 6 is a conceptual perspective view showing the configuration of the fourth embodiment.

FIG. 7 is a partially enlarged view showing the shape of a unit positioning pin according to the fourth embodiment.

FIG. 8 is a schematic side view of a process unit according to the fourth embodiment.

FIG. 9 is a partial plan view of the process unit according to the fourth embodiment.

FIG. 10 is a partial plan view of a process unit according to the fifth embodiment.

FIG. 11 is a conceptual cross-sectional view of an essential part showing an engaged state of a pin and a hole in the fifth embodiment.

FIG. 12 is an explanatory view showing a supporting structure of a process unit in a conventional example.

[Explanation of symbols]

 4 process unit 18, 19 support member 20 photoconductor drum 21 process unit side plate 22a, 22b positioning hole 23a, 23b positioning pin 26, 27 guide rail 29 unit positioning pin 33 gear positioning pin 36, 37 positioning hole 41 positioning pin 43 opening 100 copiers

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Nobuhiko Umezawa 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (6)

[Claims] 1. An image forming apparatus in which a plurality of image forming units are detachably mounted between at least two supporting members arranged on the front side of the apparatus, wherein the image forming unit is disposed on the front side of the image forming unit. An image forming apparatus, wherein a side surface member is supported by the at least two supporting members. 2. The image forming apparatus according to claim 1, further comprising engaging means for engaging the side member of the image forming unit and the at least two supporting members at predetermined positions. . 3. The image forming apparatus according to claim 1, further comprising engaging means for engaging a side member disposed on the inner side of the image forming unit with the main body of the apparatus at a predetermined position. Image forming apparatus. 4. The image forming apparatus according to claim 2 or 3, wherein the engaging means includes a positioning hole and a positioning pin. 5. The image forming apparatus according to claim 1, further comprising fixing means for detachably fixing the image forming unit to the apparatus main body. 6. The image forming apparatus according to claim 1, further comprising guide means for supporting the image forming unit and guiding the unit in a detaching direction.