JP2000231321A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plotter in which a photoreceptor is incorporated in a plotter body, an openable and closable transfer cover in which a transfer roller is supported, and a recording medium in a transfer portion facing the transfer roller and the photoreceptor. In an image forming apparatus having a paper feeding unit for feeding, the inside of the plotter unit is largely opened by opening the transfer cover. SOLUTION: When a transfer cover 3 is closed, a lower portion of a transfer cover 3 is pivotally connected to a sheet feeding section 2 and the transfer cover 3 is positioned with respect to the plotter section 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plotter unit in which an image carrier having a toner image formed on the surface is incorporated in a plotter body, and a recording medium set in a paper feeding unit body. A paper supply unit, and an openable and closable transfer cover supporting a transfer device, wherein the paper supply unit is disposed below the plotter unit, and the paper supply unit and the plotter unit are separable. The recording medium fed from the paper supply unit is transported to a transfer unit where the image carrier and the transfer device are opposed to each other, and the toner image formed on the surface of the image carrier is transferred to the recording medium surface. An image forming apparatus, wherein the transfer cover is formed by a cover guide of a transfer cover portion facing the plotter portion and a plotter guide of a portion of the plotter portion facing the cover guide when the transfer cover is closed. Recording medium conveyed to It constitutes a transport route of use, by opening the transfer cover, an image forming apparatus for opening the plotter guide outside.

[0002]

2. Description of the Related Art An image forming apparatus of the above-mentioned type constituted as an electronic copying machine, various printers, a facsimile or a multifunction machine having at least two of these functions has been conventionally known.

In this type of image forming apparatus, the plotter section and the sheet feeding section are assembled so as to be separable, so that the plotter section and the sheet feeding section can be separately assembled at the time of manufacturing the image forming apparatus. Workability during assembly can be improved. Further, when the image forming apparatus is transported to a user, for example, the plotter unit and the paper feed unit can be transported in a separated state, so that these can be transported easily, and the plotter unit and the paper feed unit can be easily assembled at the user. It is possible.

On the other hand, in the image forming apparatus of the type described above, the plotter guide can be exposed to the outside by opening the transfer cover, and the conveyance path of the recording medium can be opened. It is possible to process.

In this type of image forming apparatus, when the transfer cover is closed, it is necessary to increase the relative positional accuracy between the transfer device supported by the transfer cover and the image carrier mounted on the plotter body. is there. If the relative positional accuracy between the transfer device and the image carrier is greatly reduced, when transferring the toner image formed on the image carrier surface to the recording medium surface,
Transfer failure occurs, and the image quality of the toner image transferred to the recording medium deteriorates.

For this reason, conventionally, the transfer cover is pivotally attached to the plotter body, and the relative position accuracy between the transfer cover and the plotter body is increased, so that the transfer device and the image carrier when the transfer cover is closed. I tried to improve the position accuracy with my body. However, with this configuration, the recording medium is jammed in the transport path, and when the transfer cover is opened to remove the recording medium, the recording medium transport path below the plotter main body cannot be largely opened. For this reason, if the leading end of the recording medium fed from the paper feeding unit reaches the plotter body or becomes jammed where it does not reach, the transfer medium pivotally attached to the plotter unit located above the paper feeding unit. Simply opening the cover does not allow the guide of the paper feed unit to obstruct, so it is not possible to determine whether or not a jammed recording medium exists, and the operator determines that the recording medium does not exist in the transport path. Then, the transfer cover may be closed as it is. In addition, even if the presence of a jammed recording medium is somehow understood, it is not often difficult to remove the recording medium.

Therefore, it is conceivable that the transfer cover is not pivotally attached to the plotter main body but is pivotally attached to the paper feeding unit main body. With this configuration, when the clogged recording medium is processed, the transfer cover can be opened to open the recording medium conveyance path portion below the plotter, so that the clogged recording medium can be easily removed. Becomes

However, since the sheet feeding section and the plotter section are assembled so as to be separable, it is generally unavoidable that the vertical relative positions of the plotter section and the sheet feeding section become somewhat inaccurate. Therefore, when the transfer cover is pivotally attached to the paper feeding unit main body and the transfer cover is positioned with respect to the paper feeding unit, when the transfer cover is closed, the transfer device provided on the transfer cover and the image provided on the plotter main body are provided. The accuracy of the relative position in the vertical direction with respect to the carrier is reduced, and a transfer failure occurs when the toner image on the surface of the image carrier is transferred to the recording medium surface during image formation, and the image quality of the transferred toner image may be reduced. I can not escape.

[0009]

SUMMARY OF THE INVENTION The present invention has been made based on the above-described novel recognition, and an object of the present invention is to open a transfer cover so that a clogged recording medium can be removed more than before. An image of the type described at the beginning, which can be easily removed, and when the transfer cover is closed, the relative positional accuracy between the transfer device provided on the transfer cover and the image carrier disposed on the plotter body can be kept high. An object of the present invention is to provide a forming apparatus.

[0010]

According to the present invention, there is provided an image forming apparatus of the type described at the beginning, wherein the transfer cover is movable vertically when the transfer cover is closed. When the transfer cover is pivotally attached to the paper feeding unit main body and the transfer cover is closed,
An image forming apparatus comprising: a positioning unit that regulates a vertical position of the transfer cover with respect to the plotter body; and a lock unit that locks the transfer cover to the plotter unit when the transfer cover is closed. We propose (Claim 1).

At this time, with the transfer cover closed,
It is advantageous that the transfer cover portion facing the paper feeding section is configured as a lower guide for the recording medium fed from the paper feeding section.

3. The image forming apparatus according to claim 2, wherein the sheet feeding section includes a swingable guide member for a recording medium at a portion facing a lower guide of the transfer cover in a closed state. It is advantageous to have (claim 3).

Further, in the image forming apparatus according to the third aspect, when the transfer unit opens the transfer cover,
It is advantageous to provide an urging means for urging the guide member in the opening direction of the transfer cover (claim 4).

The image forming apparatus according to any one of claims 1 to 4, further comprising a pair of registration rollers for transporting the recording medium to a transfer section at a predetermined timing, wherein one of the registration rollers of the pair of registration rollers is provided. Advantageously, the roller is supported by the plotter body and the other registration roller is supported by the transfer cover.

The image forming apparatus according to any one of claims 1 to 5, further comprising a reflection type photo sensor for detecting the amount of toner attached to the pattern toner image formed on the surface of the image carrier. Advantageously, a mold photosensor is arranged on the transfer cover (claim 6).

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic sectional view showing the internal structure of an image forming apparatus configured as a laser printer. The image forming apparatus shown here has a plotter unit 1, a paper feed unit 2 located below the plotter unit 1, and a transfer cover 3 that can be opened and closed as described later. A scanner unit (not shown) is placed on the upper side of the plotter unit 1, and a document image can be read by the scanner unit and the image can be copied, so that a function as a copying machine can be provided.

The plotter section 1 has a plotter main body 4 which constitutes the entire casing, and a process unit 5 is detachably mounted inside the plotter body 4. Process unit 5
Is a drum-shaped photoreceptor 7 rotatably supported by the unit case 6, a charging roller 8, which is an example of a charging device also rotatably supported by the unit case 6, a developing device 9, and a cleaning device. 10 is provided. As described above, the photoconductor 7 is supported by the plotter main body 4 via the unit case 6 and is incorporated in the plotter main body 4. However, the photoconductor can be directly supported by the plotter main body 4. The photoconductor 7 is an example of an image carrier on which a toner image is formed on the surface.

The developing device 9 includes a developing case 11 formed by a part of the unit case 6 and the developing case 11.
And a developing roller 12 rotatably supported in the developing case 11, and a developer D is accommodated in the developing case 11. In this example, a powdery two-component developer having a toner and a carrier is used, but another type of developer may be used.

The cleaning device 10 includes a cleaning case 13 formed by a part of the unit case 6, a cleaning blade 14 as an example of a cleaning member supported by the cleaning case 13, and a toner collecting screw disposed in the cleaning case 13. 15.

A transfer roller 22, which is an example of a transfer device, is rotatably supported on the transfer cover 3. When the transfer cover 3 is closed as shown in FIG. In contact with the surface of As described above, the transfer device is supported on the transfer cover 3, and therefore, the cover 3 is referred to as a transfer cover.

When the image forming operation is started, the photosensitive member 7
Is rotated in a counterclockwise direction in FIG. 1 by a driving device (not shown). At this time, a voltage of a predetermined polarity applied to the charging roller 8 rotating while abutting on the surface of the photoconductor causes the surface of the photoconductor to be driven. Are uniformly charged to that polarity.

On the surface of the photoreceptor charged as described above,
A modulated laser beam L emitted from a laser writing unit 16 which is an example of an image exposure device disposed in the plotter body is irradiated, thereby forming a predetermined electrostatic latent image on the surface of the photoconductor. This electrostatic latent image is visualized as a toner image when passing through the developing device 9. That is,
The developer D is carried on the peripheral surface of the developing roller 12 which is driven to rotate, and the developer is conveyed by the rotation of the developing roller 12, and the developer D in the developing area between the developing roller 12 and the photosensitive member 7 Is electrostatically transferred to the electrostatic latent image, and the electrostatic latent image is visualized.

On the other hand, the paper supply unit 2 has a paper supply unit main body 17 constituting its housing, and two upper and lower paper supply rollers 18 and 18A rotatably supported by the paper supply unit main body 17, Paper feed cassettes 19 and 19A are detachably mounted in two upper and lower stages in the main body of the paper feed unit, and the recording media P loaded on the bottom plates 20 and 20A are accommodated in each paper feed cassette. I have. As described above, the recording medium P is set in the paper supply unit main body 17. As the recording medium P, for example, transfer paper or a plastic sheet is used, and the uppermost recording medium is the paper supply rollers 18 and 18A. Respectively. One or three or more paper feed cassettes and paper feed rollers may be provided.

Either one of the paper feed rollers 18 or 18A
Is rotated counterclockwise, the uppermost recording medium P in contact therewith is sent out from the paper feed cassette 19 or 19A. At this time, the double feed of the recording medium P is prevented by the cooperation of the separation pad 21 or 21A provided on each of the sheet feeding cassettes 19 and 19A and the rotating sheet feeding roller 18 or 18A. Only P is sent out from the sheet cassette 19 or 19A. In FIG. 1, the arrow A1 indicates the transport direction of the recording medium P when it is sent out from the upper paper feed cassette 19, and the arrow A2 indicates the transport direction of the recording medium P when it is sent from the lower feed cassette 19A. Is shown. As described above, the paper feeding unit 2 is for feeding the recording media P set in the paper feeding unit main body 17 one by one.

As described above, the leading end of the recording medium P fed from the sheet feeding unit 2 collides with the pair of registration rollers 23, where it temporarily stops, and then the toner formed on the surface of the photoreceptor is discharged. The registration roller pair 23 starts rotating at a timing when the recording medium P can be aligned with the image, and the recording medium P
The photoconductor 7 is conveyed to a transfer section between the photoconductor 7 and a transfer roller 22 which rotates while rotating in contact with the surface of the photoconductor 7 opposite thereto. At this time, a voltage having a polarity opposite to the toner charging polarity of the toner image on the photosensitive member surface is applied to the transfer roller 22, and the toner image on the photosensitive member surface is transferred to the recording medium surface. The registration roller 23A on one driving side of the registration roller pair 23 is rotatably supported by the plotter body 4, and the registration roller 23B on the other driven side is rotatably supported by the transfer cover 3, and this point will be described later. explain in detail.

It is also possible to use a transfer device other than the transfer roller 22, for example, a transfer device including a blade or a brush in contact with the surface of the photoreceptor 7, or a transfer charger disposed separately from the photoreceptor.

The recording medium P on which the toner image has been transferred is separated from the photoreceptor 7 by receiving a discharging action from the static elimination needle 27 supported on the transfer cover 3. Then, this recording medium P
Is transported further upward and passes between the fixing roller 24A and the pressure roller 24B of the fixing device 24 supported by the plotter body 4, and at this time, the toner image on the recording medium surface is acted upon by the action of heat and pressure. It is fixed on the surface. Continued
The recording medium is discharged onto a discharge tray 26 on the upper portion of the plotter body by a discharge roller pair 25.

The transfer residual toner adhering to the surface of the photoreceptor after the transfer of the toner image is scraped off by the cleaning blade 14 of the cleaning device 10 to clean the surface of the photoreceptor. Next, the surface of the photoreceptor is subjected to a charge removing operation by light from a charge removing lamp (not shown), and the surface potential is initialized. The toner removed from the photoreceptor surface by the cleaning blade 14 is discharged out of the cleaning case 13 by the toner collecting screw 15 and reused in the developing device 9.

When it is detected that the toner concentration of the developer contained in the developing case 11 of the developing device 9 has decreased, toner is supplied to the developing case 11 from a toner container (not shown).

As described above, the recording medium P fed from the paper supply unit 2 is conveyed along the conveyance path extending almost vertically from bottom to top, and is finally stacked on the paper discharge tray 26. You. FIG. 1 shows a state in which the transfer cover 3 is closed. In this state, the transfer cover 3 facing the plotter unit 1 is shown.
The cover guide 28 is constituted by the portion of the plotter section 1, and the plotter guide 29 is formed by the portion of the plotter section 1 facing the cover guide 28.
9 constitutes a conveyance path of the recording medium conveyed to the transfer section between the photoconductor 7 and the transfer roller 22. In the illustrated example, a plotter guide 29 is configured by a guide plate fixed to the plotter body 4 and a part of the unit case 6 of the process unit 5, and a cover guide 28 is configured by a wall surface of the transfer cover 3.

An intermediate roller 30 rotatably supported by the plotter body 4 is provided between the paper feed roller 18 and the registration roller pair 23.
When the recording medium P is pulled by the registration roller pair 23, the recording medium is guided to prevent the recording medium from being strongly rubbed against the plotter guide 29 due to an excessively strong tensile force.

Here, the sheet feeding unit 2 and the plotter unit 1 placed thereon are assembled so as to be splittable. For example, a positioning pin (not shown) protruding from one of the sheet feeding unit 2 and the plotter unit 1 is fitted into a positioning hole (not shown) formed on the other side, and both are positioned. In this state, the paper feed unit is separated from the plotter unit 1 by separating the bolt and the nut by fixing them together by fixing means such as a bolt and a nut. 2 and the plotter unit 1 are assembled. As described above, by assembling the sheet feeding unit 2 and the plotter unit 1 so as to be separable, the plotter unit 1 and the sheet feeding unit 2 can be easily assembled at the time of manufacturing the image forming apparatus. These can be easily transported at the time of transportation.

Further, in the image forming apparatus shown in FIG. 1, the transfer cover 3 can be opened and closed with respect to the plotter body 4 as described above. That is, the transfer cover 3 is rotatably opened and closed between a vertically closed position shown in FIG. 1 and an inclined open position shown in FIG.
The lower part is supported. Therefore, when the transfer cover 3 is opened as shown in FIG. 2, the plotter guide 29 is opened to the outside. Therefore, when the recording medium is jammed in the transport path, the transfer cover 3 is opened, the transport path is opened,
The recording medium jammed here can be easily removed.

As described above, the image forming apparatus according to the present embodiment includes the plotter unit 1 in which the image carrier composed of the photoreceptor 7 on the surface of which the toner image is formed is incorporated in the plotter body 4, the paper supply unit body 17 A sheet feeding unit 2 for feeding the recording medium P set one by one, and an openable and closable transfer cover 3 on which a transfer roller 22 as an example of a transfer device is supported. The paper supply unit 2 and the plotter unit 1 are arranged under the plotter unit 1 so that the paper supply unit 2 and the plotter unit 1 can be separated from each other. The toner image formed on the surface of the image carrier is transferred to the recording medium surface. Moreover, in this image forming apparatus, with the transfer cover 3 closed, the cover guide 28 of the transfer cover portion facing the plotter portion 1 and the plotter guide 29 of the portion of the plotter portion 1 facing the cover guide 28. Thus, a transfer path for the recording medium to be transferred to the transfer unit is formed, and the plotter guide 29 can be opened to the outside by opening the transfer cover 3.

Here, when performing the image forming operation with the transfer cover 3 closed, it is necessary to increase the relative positional accuracy between the transfer roller 22 and the photosensitive member 7 in order to increase the transfer efficiency of the toner image onto the recording medium P. . Therefore, as described above, in the conventional image forming apparatus, the lower portion of the transfer cover is pivotally attached to the plotter main body, and the transfer cover is correctly positioned with respect to the plotter main body. And the position accuracy of the photoreceptor was improved. However, according to this configuration, even when the transfer cover is opened, the lower region of the recording medium transport path is not opened. For this reason, the recording medium fed from the paper feed roller and jammed where the leading end reaches or does not reach the plotter body cannot be easily removed by opening the transfer cover. I can not avoid the shortcomings described.

If the transfer cover is pivotally attached to the main body of the paper feeding section, the above-mentioned disadvantages can be eliminated. However, if this configuration is simply employed, the paper feeding section and the plotter section can be divided. As described above, there is a possibility that the relative positional accuracy of the image carrier and the transfer roller in the vertical direction may decrease during image formation. As described above, the upper part of the paper feeding unit 2 and the lower part of the plotter unit 1 are positioned and connected by, for example, a positioning pin and a positioning hole in which the positioning pin is fitted. The transfer cover 22 is located above the positioning connection portion between the sheet feeding portion 2 and the plotter portion 1.
Is simply attached to the paper supply unit main body 17, the paper supply unit 2 and the plotter unit 1 are only slightly inaccurately assembled, and the relative positional accuracy of the photoreceptor 7 and the transfer roller 22 in the vertical direction is increased. Is reduced.

Therefore, in the image forming apparatus of this embodiment,
When the transfer cover 3 is closed, the transfer cover 3 is movable in the vertical direction, and the transfer cover 3 is
7 and a positioning means for regulating the vertical position of the transfer cover 3 with respect to the plotter body 4 when the transfer cover 3 is closed, and the transfer cover when the transfer cover 3 is closed. Lock means for locking the plotter 3 to the plotter body 4 of the plotter unit 1 is provided. Hereinafter, a more specific configuration example will be clarified.

FIG. 3 is a perspective view showing the transfer cover 3 detached from the plotter main body 4 and the paper feeding unit main body 17.
As shown in FIG. 1, the plotter main body 4 of the present example is composed of a frame 32 and an outer cover 33 covering the same. Similarly, the paper feeder main body 17 is also composed of a frame 34 and an outer cover 35 covering the same. 3 includes a pair of spaced side plates 32A, 32 constituting a frame 32 of the plotter body 4.
B, and a pair of spaced side plates 34A, 34B constituting the frame 34 of the sheet feeding unit main body 17 are shown, and the outer covers 33, 35 and the bottom plate 32 of the frames 32, 34 are shown.
Illustrations of C and 34C (see FIGS. 1 and 2) are omitted.

As can be seen from FIGS. 1 to 3, when the transfer cover 3 is in the closed position shown in FIG. 1, the lower portion of the transfer cover 3 has a pair of first concave portions 31 and 31A.
Are formed respectively. Further, a pair of concentric pivot pins 36, 36A are fixed to a pair of side plates (hereinafter, referred to as sheet supply side plates) 34A, 34B of the sheet supply unit main body 17, and the above-described first concave portions 31, 31A are fixed. However, as shown in FIG. 1 and FIG. 2, the pivot pins 36 and 36A are fitted to each other so as to be relatively rotatable.

As described above, the transfer cover 3 is
6 and 36A, the transfer cover 3 is pivotally attached to the paper supply unit main body 17 via the pivot pins 36, 36.
A can be freely opened and closed around A between the closed position shown in FIG. 1 and the open position shown in FIG. that time,
The transfer cover 3 is not pivotally attached to the plotter main body 4 but is pivotally attached to the paper supply unit main body 17 located below the plotter main body 4. Therefore, when the transfer cover 3 is opened as shown in FIG.
The area of the recording medium transport path below the plotter body 4 is also opened to the outside. From the feed roller 18 to the photosensitive member 7
The recording medium transport path leading to is greatly opened.
For this reason, when a recording medium is jammed in this conveyance path,
When the transfer cover 3 is opened, the presence of the jammed recording medium can be easily confirmed, and the recording medium can be easily removed. Even if the recording medium is fed from the paper feed roller 18 and reaches the plotter main body 4 or becomes unreachable,
This is surely visible and can be easily removed.

When the transfer cover 3 is closed as shown in FIG. 1, each of the first recesses 31 and 31A extends vertically in the vertical direction, and its lower end is open. In addition, when the transfer cover 3 is closed in a state where the first concave portions 31 and 31A are fitted to the pivot pins 36 and 36A protruding from the sheet feeding side plates 34A and 34B, respectively, the transfer cover 3 moves in the horizontal direction. Each first recess 31A,
The width of 31B and the diameter of the pivot pins 36, 36A are set. Therefore, when the transfer cover 3 is closed as shown in FIG.
The transfer cover 3 is accurately positioned in the horizontal direction with respect to the sheet feeding unit 2.

On the other hand, each of the first concave portions 31 and 31A
The first recess 3 is provided for each pivot pin 36, 36A.
Each pivot pin 3 is slidable in the long and extended direction of 1, 31A.
6, 36A. When the transfer cover 3 is closed as shown in FIG. 1, each of the first recesses 31 and 31A
To be able to move up and down relative to 6,36A,
That is, they are fitted with play. As described above, when the transfer cover 3 is closed, the transfer cover 3 is pivotally attached to the sheet feeding unit main body 17 in a state where the transfer cover 3 can freely move up and down.

On the other hand, as shown in FIGS. 1 to 3, a pair of second concave portions 37, 37A are formed in the transfer cover 3, and a pair of side plates (hereinafter referred to as plotter side plates) 32A, 32B, concentric upper and lower positioning pins 38, 38A are fixedly provided, respectively. When the transfer cover 3 is closed as shown in FIG.
37A is fitted to the upper and lower positioning pins 38, 38A projecting from the plotter side plates 32A, 32B without play. For this reason, the transfer cover 3 is correctly positioned in the vertical direction with respect to the plotter main body 4, whereby the transfer roller 22 supported by the transfer cover 3 and the photoconductor 7 mounted on the plotter main body 4 are correctly contacted with high accuracy. Touch

When the transfer cover 3 is opened as shown in FIG.
Each of the second concave portions 37 and 37A is provided with each of the upper and lower positioning pins 38,
38A, but if the transfer cover 3 is closed again, the second concave portions 37, 37A and the upper and lower positioning pins 38, 38A
Are fitted, and the transfer cover 3 is positioned in the vertical direction. Therefore, during the image forming operation, the toner image on the photoreceptor can be transferred onto the recording medium P satisfactorily and efficiently, and a high-quality image can be formed on the recording medium. Thus, the second recesses 37, 37A and the upper and lower positioning pins 38, 38
A is an example of positioning means for regulating the vertical position of the transfer cover 3 with respect to the plotter body 4 when the transfer cover 3 is closed, and for correctly positioning the transfer cover 3 in the vertical direction.

As described above, in the image forming apparatus of the present embodiment, the transfer cover 3 is pivotally attached to the paper supply unit main body 17. At this time, the transfer is performed with the transfer cover 3 closed. When the transfer cover 3 is closed, the cover 3 is pivotally attached to the paper supply unit main body 17 so that the cover 3 can freely move in the vertical direction. The transfer cover 3 is configured to be positioned vertically with respect to the main body 4. With this configuration, even when the plotter unit 1 and the paper feeding unit 2 are assembled with some inaccuracy, when the transfer cover 3 is closed, the relative positional accuracy between the transfer cover 3 and the plotter unit 1 in the vertical direction is improved. Can be. Of course, elements other than the cover guide 28 of the transfer cover 3 and the transfer roller 22 attached to the transfer cover 3, for example, the registration roller 2
The positional accuracy of the 3B and the static elimination needle 27 with respect to the plotter unit 1 can also be improved.

In the illustrated example, with the transfer cover 3 closed, the vertical positioning pins 38, 38A are connected to the pivot pins 36, 38A.
The upper and lower positioning pins 38, 38A located above the transfer roller 22 and above the transfer roller 22 regulate the vertical position of the transfer cover 3 so that the transfer to the photoconductor 7 is performed. The vertical position accuracy of the roller 22 can be further enhanced.

As shown in FIGS. 1 to 3, the base ends of a pair of lock levers 39, 39A are pivotally supported by the transfer cover 3 via pins 46, 46A. The lock levers 39 and 39A are urged to rotate clockwise in the drawing by the action of a spring (not shown). Moreover, when the transfer cover 3 is opened, the lock levers 39 and 39A are held at the positions shown in FIGS. 2 and 3 by stoppers (not shown).

On the other hand, a pair of plotter side plates 32A, 32B
Are provided with lock pins 40, 40A to which the lock levers 39, 39A engage. When the transfer cover 3 is closed, first, the lock levers 39, 39 pivotally supported by the lock pins 39, 39A.
1A hits the lock pins 40 and 40A, the lock levers 39 and 39A slightly rotate counterclockwise in FIG. 1, and then the lock pins 40 and 40A are moved to the distal ends of the lock levers 39 and 39A. When the transfer cover 3 is completely closed, the lock levers 39, 3
9A, the tip hook portion engages with each of the lock pins 40, 40A as shown in FIG. 1 by the action of the above-mentioned spring, and the transfer cover 3 is locked. Thereby, the transfer cover 3
Is prevented from being opened carelessly.

When the transfer cover 3 is closed, the transfer cover 3 includes the pivot pins 36 and 36A and the lock pins 40 and 4.
It is positioned in the horizontal direction by 0A, and is positioned in the vertical direction by the vertical positioning pins 38, 38A.

When the lock levers 39 and 39A are rotated counterclockwise in FIG. 1 by operating an operation lever (not shown), the lock levers 39 and 39A engage with the lock pins 40 and 40A. Then, the transfer cover 3 can be opened as shown in FIG.

As described above, the lock levers 39, 39A and the lock pins 40, 40A constitute an example of a lock means for locking the transfer cover 3 to the plotter unit 1 when the transfer cover 3 is closed. .

Further, as can be seen from FIG.
With the cover closed, the transfer cover portion facing the paper supply unit 2 is provided with a lower guide 4 for the recording medium fed from the paper supply unit 2.
1 is configured. The opening / closing fulcrum of the transfer cover 3 is arranged at a position where it enters the paper feeder 2 side, and the recording medium fed from the paper feeder 2 is transferred to the lower guide 41 of the transfer cover 3.
It is guided by. In the example of FIG. 1, the lower guide 41 serves to guide the recording medium fed from the upper sheet cassette 19 and the recording medium fed from the lower sheet cassette 19A, respectively.

As described above, the transfer cover portion facing the sheet feeding section 2 is configured as the lower guide 41, so that a special guide member is not provided and the transfer cover portion immediately after the sheet is fed from the sheet cassette. It is possible to reliably guide the recording medium. In addition, since the lower guide 41 is formed by a part of the transfer cover 3, opening the transfer cover 3 greatly opens the recording medium transport path formed by the lower guide 41. The clogged recording medium can be easily removed.

Also, as shown in FIG.
A guide member 42 for guiding the recording medium is provided at a portion of the sheet feeding section 2 facing the recording medium 1, and in the example of FIG.
Is configured to guide the recording medium P sent from the uppermost sheet feeding cassette 19. At this time, the guide member 42 can swing between the use position shown in FIG. 1 and the retracted position rotated in the opening direction of the transfer cover 3 as shown in FIG. The paper feed unit 17 is pivotally supported. As described above, the sheet feeding section 2 of the present example has the swingable guide member 42 for the recording medium at a portion facing the lower guide 41 of the transfer cover 3 in the closed state. .

According to the above configuration, when the transfer cover 3 is opened as shown in FIG.
By rotating the recording medium 2 to the retracted position shown in FIG. 2, the conveyance path for the recording medium immediately after being fed from the paper feed roller 18 can be greatly opened, and the recording medium jammed here can be easily removed. Can be.

When the transfer cover 3 is opened, the guide member 42 is rotated to bias the guide member 42 to the retracted position automatically. It is particularly advantageous to provide means. In this case, as shown in FIG. 3, a pressing portion 43 is protruded from the transfer cover 3, and when the transfer cover 3 is closed, the guide member 42 at the retracted position is shown in FIG. When the guide member 42 is configured to be pressed and rotated to the used position, the guide member 42 can be automatically returned to the used position. As described above, in this example, when the sheet supply unit 2 opens the transfer cover 3, the sheet supply unit 2 includes the urging unit that urges the guide member 42 in the opening direction of the transfer cover 3. Processing of the medium can be performed more easily.

Incidentally, the image forming apparatus of this embodiment has a pair of timing rollers 23 for conveying the recording medium P to the transfer section at a predetermined timing. If the roller pair 23 is left on the plotter body 4 as it is, the roller pair 23
When the recording medium is clogged between them, even if the transfer cover 3 is opened, it is difficult to remove the recording medium.

Therefore, in the image forming apparatus of this embodiment,
As described above, one registration roller 23A on the driving side of the registration roller pair 23 is rotatably supported by the plotter body 4, and the other driven registration roller 23B is driven.
Are rotatably supported by the transfer cover 3. According to this configuration, when the transfer cover 3 is opened, one of the registration rollers 23A is left on the plotter body 4 and the other registration roller 23B moves together with the transfer cover 3, so that the space between the two registration rollers 23A and 23B is established. , As shown in FIG. For this reason, the recording medium transport path can be opened much more, and the visibility and removal of the jammed recording medium can be further improved.

In the image forming apparatus as shown in FIG. 1, a pattern toner image is formed on the surface of the photoreceptor 7 by the developing device 9, and the amount of toner attached is detected by a reflection type photo sensor. For example, when the toner concentration of the developer D of the developing device 9 is detected, and when it is detected that the toner concentration decreases, the toner is supplied to the developing case 11 of the developing device 9 as described above. This reflection type photo sensor has a light emitting unit and a light receiving unit.

At this time, especially when the photosensitive member is made of a drum, the light is emitted from the light emitting portion of the reflective photosensor and is emitted on the side of the photosensitive member due to a decrease in the positional accuracy of the photosensitive member and the reflective photosensor. The reflected light may not be correctly incident on the light receiving portion of the reflection type photo sensor, and the reflection type photo sensor may not function. For this reason, in the conventional image forming apparatus, the reflection type photo sensor is provided in the plotter main body, and the positional accuracy between the reflection type photo sensor and the photoconductor is enhanced. However, particularly in recent image forming apparatuses, since the size of the image forming apparatuses has been reduced, there is often no space for providing a reflection type photosensor in the plotter body.

Therefore, in the image forming apparatus of this embodiment,
As shown in FIGS. 1 to 3, the reflection type photo sensor 44 is provided to be correctly positioned on the transfer cover 3, and a window 45 for allowing light transmission is formed in a portion of the transfer cover 3 facing the sensor 44. ing. Such a photo sensor 4
In step 4, the amount of toner adhering to the pattern toner image formed on the photoconductor surface is detected. The image forming apparatus according to the present embodiment includes a reflection type photosensor 44 for detecting the amount of toner attached to a pattern toner image formed on the surface of an image carrier made of a photoconductor.
And the reflection type photo sensor 44 is disposed on the transfer cover 3.

According to the above configuration, even if the size of the image forming apparatus is reduced, the reflection type photo sensor 44 is provided on the transfer cover 3 side. In addition, as described above, when the transfer cover 3 is closed, the transfer cover 3 can be correctly positioned with respect to the plotter main body 4, so that the reflection type photosensor 44 provided on the transfer cover 3 The relative position accuracy can be improved. As a result, the function of the reflection type photosensor 44 can be ensured, whereby a high quality toner image can always be formed on the photoconductor.

The present invention can be applied to various image forming apparatuses other than those shown in the figures, and can be configured by variously modifying the above-described configuration. For example, the present invention can be applied to an image forming apparatus in which a toner image formed on a photoreceptor is transferred to the surface of an intermediate transfer member, and the toner image on the surface of the intermediate transfer member is transferred to a recording medium. The above-mentioned intermediate transfer member constitutes an image carrier on which a toner image is formed.

[0065]

According to the first aspect of the present invention, when the transfer cover is opened, the portion of the recording medium transport path below the plotter body is also opened, so that the jammed recording medium can be easily removed. In addition, it is possible to prevent the relative position accuracy between the transfer device and the image carrier from being lowered.

According to the second aspect of the present invention, the recording medium fed from the paper feeding section can be guided by the lower guide formed by the transfer cover itself, so that the cost of the image forming apparatus can be suppressed and the transfer can be suppressed. When the cover is opened, the recording medium transport path below the plotter body can be reliably opened.

According to the third aspect of the present invention, when the transfer cover is opened, the guide member is rotated to the retracted position, so that the recording medium conveying path defined by the guide member is largely opened. it can.

According to the fourth aspect of the present invention, when the transfer cover is opened, the guide member can be automatically turned to the retracted position.

According to the fifth aspect of the present invention, when the transfer cover is opened, the pair of registration rollers can be largely separated from each other, and the recording medium transport path can be further opened.

According to the sixth aspect of the present invention, the reflection type photosensor can be reliably arranged, and the relative position accuracy between the reflection type photosensor and the image carrier can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic vertical sectional view showing the internal structure of an image forming apparatus.

FIG. 2 is a schematic vertical sectional view when the transfer cover of the image forming apparatus shown in FIG. 1 is opened.

FIG. 3 is a perspective view illustrating a transfer cover removed from a plotter unit and a sheet feeding unit;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plotter part 2 Paper supply part 3 Transfer cover 4 Plotter main body 17 Paper supply part main body 23 Registration roller pair 23A Registration roller 23B Registration roller 28 Cover guide 29 Plotter guide 41 Lower guide 42 Guide member P Recording medium

Continued on front page F term (reference) 2H027 DA10 DE02 DE10 HB18 2H032 AA05 BA23 2H071 AA02 AA06 AA08 AA20 DA23 DA32 EA00 2H072 AA02 AA13 AA15 AA22 AB04 AB07 BA03 BA08 BA12 CB07 CB08 CB09 EA18

Claims (6)

[Claims] 1. A plotter section in which an image carrier having a toner image formed on a surface is incorporated in a plotter main body, a paper feeding section for feeding recording media set in the paper feeding section main body one by one,
An openable and closable transfer cover on which a transfer device is supported, wherein the paper supply unit is disposed below the plotter unit, and the paper supply unit and the plotter unit are assembled so as to be splittable; An image forming apparatus that conveys a recording medium fed from a paper unit to a transfer unit where the image carrier and the transfer device are opposed to each other, and transfers a toner image formed on the surface of the image carrier to the surface of the recording medium. With the transfer cover closed, the recording sheet conveyed to the transfer section by the cover guide of the transfer cover portion facing the plotter portion and the plotter guide of the plotter portion facing the cover guide. In an image forming apparatus configured to form a conveyance path for a medium and open the transfer cover to open the plotter guide to the outside, when the transfer cover is closed, the transfer cover moves vertically. Movably, the transfer cover is pivotally attached to the paper feeding unit main body, and when the transfer cover is closed, positioning means for regulating the vertical position of the transfer cover with respect to the plotter main body, An image forming apparatus comprising: a lock unit configured to lock the transfer cover to the plotter unit when the transfer cover is closed. 2. The image forming apparatus according to claim 1, wherein, with the transfer cover closed, a transfer cover portion facing the sheet feeding section is configured as a lower guide for the recording medium fed from the sheet feeding section. Image forming apparatus. 3. The image forming apparatus according to claim 2, wherein the sheet feeding unit includes a swingable guide member for a recording medium at a portion facing a lower guide of the transfer cover in a closed state. . 4. The image forming apparatus according to claim 3, wherein the sheet feeding unit includes an urging unit that urges the guide member in an opening direction of the transfer cover when the transfer cover is opened. 5. A registration roller pair for conveying the recording medium to a transfer section at a predetermined timing, wherein one of the pair of registration rollers is supported by a plotter body, and the other is supported by a transfer cover. The image forming apparatus according to claim 1, wherein: 6. A reflection type photo sensor for detecting the amount of toner attached to a pattern toner image formed on the surface of an image carrier, wherein the reflection type photo sensor is disposed on the transfer cover. The image forming apparatus according to any one of the above.