JP3398064B2 - 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 for reproducing a visible image on a sheet as necessary and outputting it as a hard copy, particularly a copying machine, a printer, a facsimile, or one of them. The present invention relates to an integrated composite image forming apparatus.

[0002]

2. Description of the Related Art For example, a digital copying machine as an image forming apparatus reads an image of a document by itself, performs image processing on the read image data (image information) according to an appropriately set condition, and visualizes this on a sheet. It has a print function for playing back as an image and outputting it as a hard copy.

Therefore, the digital copying machine is connected to a plurality of image input devices such as a facsimile machine and a personal computer via a communication line, and the image data sent from the facsimile machine is stored in the digital copying machine. The print function is used to reproduce a visible image on a sheet and output it as a hard copy. Therefore, the digital copier itself has a function as a facsimile device. Therefore, the transmission original is read, and the read image data is transmitted to another image forming apparatus, for example, a digital copying machine or a printer itself having a facsimile function, and a hard copy can be output by the other party. .

The image input device is not the image forming device itself having a facsimile function, and there are word processors and other devices in addition to the personal computer described above. Image data such as characters and images created by these devices and graphs and figures are output as a visible image on a sheet as necessary. Therefore, an image forming apparatus such as a digital copying machine or a printer is used. These image input devices (input means) and image forming devices are connected to each other via a communication line, and image data, commands, etc. are transmitted / received, and a printer or digital device in which necessary image data is designated. It can be output as a hard copy via a copying machine.

As the image forming apparatus, a composite type apparatus which can be operated as a copying machine, a printer, and a facsimile is integrated, or each of them operates independently to output a hard copy. It has been used as needed and has become very convenient.

Therefore, for the user, in order to maintain the output function of the image forming apparatus at all times, various operations described below are simplified, the burden on the user is reduced, and the apparatus can be downsized. It is desired to reduce the floor area occupied by the device (the area where the device is arranged).

By the way, there are the following operations performed by the user on the image forming apparatus. In order to obtain a hard copy, the sheet is fed by the accommodating section, is fed along the various conveyance paths to the image forming position of the image forming section for image formation, and is discharged out of the image forming apparatus after image formation. for that reason,
Sheet jammed (jammed) in one of the transport paths
Sometimes, one of them is jam removal work to remove the sheet.

Further, a sheet replenishing operation for replenishing sheets for obtaining a hard copy into a sheet accommodating section such as a sheet feeding cassette or a sheet feeding tray, which will be described later, and a sheet ejecting section for receiving ejected hard copy sheets. There is a handling of completed products to be removed. The above is a processing operation that is frequently performed by the user regarding the handling of sheets as necessary.

In addition to the sheet processing operation, an image forming unit for forming an image in the image forming apparatus, a conveying unit such as a sheet conveying path and a conveying unit, and various components forming the image forming unit are provided. There is a maintenance work for performing the replacement by life, cleaning, replenishment, etc. to maintain the print function of the image forming apparatus at all times.

The above-mentioned various operations performed by the user themselves have different frequencies, and the finished product handling operation has the highest frequency. It can also be said that maintenance work is the least frequent. Either the sheet replenishing work or the jam clearance work has a higher frequency depending on the form of the sheet storage capacity and the type of the sheet, but in general, the sheet replenishing work has a higher frequency. There are many.

As a means for coping with the demand for facilitating the workability of the user, there is one disclosed in the specification of Japanese Patent No. 2595905 (Japanese Patent Laid-Open No. 8-67355). The image forming transport path, which passes through the image forming position of the image forming unit, the image forming unit, the sheet accommodating unit, and the paper discharge unit are stacked in this order in the upward direction, and the image forming apparatus is installed. We try to minimize the floor space.

Moreover, the paper discharge unit, the sheet storage unit, and the writing unit (by a laser) are integrally supported by the main body of the image forming apparatus, particularly the printer main body, and these are rotated integrally to form the image forming unit. It is configured so that a part thereof is opened, and a sheet discharge section is provided so as to be opened independently so that the sheet storage section can be opened.

Therefore, it is not necessary to make the accommodating portion drawable when replenishing the sheet, so that a space for drawing out is unnecessary. As a result, the floor area occupied by the printer (image forming apparatus) body described above can be further reduced. In addition, the paper discharge section related to the most frequently completed work handling work is arranged on the top of the printer, and the sheet storage section related to the next most frequent work sheet supply work is arranged below the discharge section for the user. I try to improve the workability.

In addition to the above disclosed technology, Japanese Patent Laid-Open No. 4-5610 discloses the following technology. In other words, the sheet storage section is arranged in the lower part of the printer body, and the image forming section,
It is specified that the image forming transporting path is arranged, and the image forming section and the sheet discharging section are arranged in parallel with the image forming transporting path above the sheet storage section.

Nothing is arranged above the paper discharge section. Further, the lower sheet storage portion is detachably provided in the printer body. With this configuration, the jam handling work, the sheet replenishing work, and the completed product handling work can be independently performed, so that the workability of the user is enhanced.

Since the laser writing unit that constitutes the image forming section is not rotated integrally with other parts during jam processing, etc., the user performs the jam processing operation somewhat violently. Even if the opening / closing operation is performed, the impact due to the opening / closing is small, and the laser writing unit, which is weak against the impact, can be sufficiently protected. Further, even if the fixing unit is provided above the laser writing unit so as to be located in a part of the image forming transport path, the heat of the heat fixing unit tends to increase the hot air, and the heat is weak to the laser writing unit. Minimal impact.

[0017]

The conventional image forming apparatus disclosed in the above publications has the above-mentioned advantages, but as described below, the above-mentioned demands are sufficiently satisfied. Is not achieved.

For example, in the patent publication of Japanese Patent No. 2595905, maintenance of the image forming unit is performed by integrally rotating the paper discharge unit, the sheet storage unit, and the laser writing unit to open the image forming unit. Although the work can be easily performed, as described above, the laser writing unit receives a large impact, and there is a risk that an image shift or the like may occur during image formation (image formation).

Moreover, in order to carry out the jam clearance work,
The operation is troublesome because it is necessary to remove the image forming unit from the printer main body each time to open the image forming transport path located under the image forming unit. In other words, the maintenance work of the image forming unit is less frequent than the jam clearance work,
Regardless of maintenance work, it is necessary to perform the removal work and the jam sheet removal work as in the maintenance work. Therefore, the parts that make up the image forming unit during work,
For example, there is a risk of damaging the photoconductor, the image carrier, and the like.

Further, since the sheet accommodating portion and the laser writing unit are rotated at the same time, the image forming portion cannot be largely opened unless a large opening angle is secured. At the same time, if the opening angle is too large, the paper discharging portion is formed. The upper sheet may fall. Furthermore, since the laser writing unit is located above the fixing unit, the laser writing unit is exposed to the rising hot air, and it is necessary to provide a cooling means and a heat insulating member to prevent this.

Further, according to the one disclosed in Japanese Patent Application Laid-Open No. 4-5610, the image forming section and the sheet discharge section are arranged side by side above the sheet storage section, but the maximum size accommodated in the sheet storage section is set. In order to secure the stacking property of the sheets to the sheet discharge section, the sheet discharge section needs to have a size corresponding to the size. Therefore, the floor area occupied by the printer becomes large. In addition, it is necessary to secure a space for pulling out the sheet storage portion, which further increases the floor area occupied by the printer.

Therefore, in the above-mentioned prior art, even if each floor area can be kept small, the workability of other users cannot be partially improved. For example, in the case of improving the sheet processing work, the floor area occupied by the printer becomes large, and it is the current situation that a printer that satisfies both requirements, that is, an image forming apparatus has not been obtained.

An object of the present invention is to eliminate the above-mentioned problems, and to simplify the work of the user and at the same time, to provide an image forming apparatus capable of minimizing the floor area occupied by the image forming apparatus. To provide.

[0024]

An image forming apparatus for achieving the above-mentioned object of the present invention moves to an image forming position of an image forming unit for forming an image on a sheet fed from a sheet storage section. In an image forming apparatus configured to provide an image forming conveyance path for conveying and to perform discharge processing to a discharge section outside the apparatus after image formation, the discharge section is exposed at the top of the image forming apparatus. provided, the sheet storage portion for storing an sheet over bets at the bottom of the sheet discharge unit, the transport path for imaging for conveying the sheet to be fed is fed from the sheet accommodating portion to the image forming position of the imaging unit , And an image forming unit provided so that the image forming position is located in the image forming conveying path, are stacked in this order, and a sheet is formed between the sheet storage unit and the image forming conveying path.
Sheets are ejected to the above paper ejection section for image formation on both sides.
It is provided by branching to the ejecting path that exits
The above-mentioned sheet accommodating section is imaged with an intervening intermediate transport path interposed.
The intermediate conveyance path is rotatably provided with respect to the main body of the image forming apparatus.
Is provided so that it can be opened, and
One of the guide members that forms an inter-conveyance path is provided .

According to the image forming apparatus having the above-described structure, the functional unit relating to the work performed by the user, which is performed more frequently, is arranged at a position where it is easier to operate. In other words, the image forming unit, the image forming conveyance path, the sheet storage unit, and the paper discharge unit are stacked in this order from the lower part to the upper part of the image forming apparatus. It will be easy.

Further, when the maximum size sheet is accommodated in the sheet accommodating portion, the sheet is surely ejected to the upper sheet ejection tray, so that the sheet ejection tray does not project, and the image forming apparatus main body When installed, the floor space it occupies will no longer increase.

[0027]

[0028]

Further, by providing the middle between conveyance path, it can be fed to the image formed sheet conveying path again created for images and becomes, can perform image formation on both surfaces, etc. of the sheet. Moreover,
Even if the intermediate conveyance path is provided, the entire image forming apparatus does not become large, and even if the maximum size sheet is conveyed, there is no problem and the sheet can be reliably fed to the image formation conveyance path.

Further, the sheet accommodating portion is rotatably provided with respect to the image forming apparatus main body so that the intermediate conveying path can be opened, and one guide member for forming the intermediate conveying path on the sheet accommodating portion side. Since the intermediate conveyance path is provided , the intermediate conveyance path can be opened as it is, and the operability of the jam processing at that portion is improved.

[0031]

[0032]

[0033] In images forming apparatus of the above configuration, the imaging unit is constituted by an electrophotographic system, it includes a laser writing unit for imaging, the laser writing unit adjacent to the image forming section A fixing unit for fixing the image on the sheet formed via the image forming unit is provided in the image forming conveying path, and the fixing unit is provided above the laser writing unit. The laser writing unit
Of the laser beam from the image forming unit that faces the image forming conveyance path.
Irradiation is performed from the side opposite to the image position, and a space portion communicating with the outside of the image forming apparatus is interposed between the laser writing unit and the fixing unit. With such a configuration, the entire apparatus does not become large even if the image forming unit including the laser writing unit is provided. In addition, the fixing unit is arranged on the upper part of the laser writing unit,
The image forming position can be downsized, and the heat of the fixing unit does not affect the laser writing unit. Further, even if various conveying paths are opened in the jam processing and the like, since they are provided in a state of being fixed to the lower part, it is possible to prevent the influence of impact or the like.

Further, the laser writing unit, between the fixing portion, by providing a space portion communicating with the outside of the image forming apparatus, cut with blocking the influence of heat.

[0035]

[0036]

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the image forming apparatus of the present invention will be described below in detail with reference to the drawings.

The present invention has a copying function such as a printer which inputs image information (image data) from the outside and outputs a hard copy as a reproduced image, and a printer which receives image data from a scanner or the like and outputs a hard copy. The present invention can be applied to a composite type image forming apparatus that simultaneously has a print function, a facsimile function, and the like.

FIG. 1 is a block diagram showing the internal structure of an image forming apparatus according to the present invention. 2 to 6
FIG. 4 is an operation explanatory diagram for explaining an output form when a hard copy is output by the image forming apparatus according to the present invention shown in FIG. 1.

First, an outline of an image forming apparatus according to the present invention and a first embodiment of the present invention will be described with reference to FIG.

(First Embodiment of the Invention) The image forming apparatus shown in FIG. 1, that is, the printer employs an electrophotographic system, and a reproduced image reproduced on a sheet uses toner as a colorant. I am trying to use it. In FIG. 1, an image forming apparatus sends an image forming unit 1 for forming an image therein and a sheet to an image forming (image forming) position of the image forming unit 1 for forming a reproduced image on the sheet. An image forming conveyance path 2 provided for that purpose, a sheet feeding cassette (sheet accommodating section) 3 arranged to convey a sheet to the image forming conveyance path 2 and temporarily accommodating the sheet, A sheet discharge tray 4 is provided which constitutes a sheet discharge unit that finally receives a sheet for which a hard copy has been completed. The paper discharge table 4 is provided so as to be exposed at the top of the main body of the image forming apparatus.

In order to feed the sheets accommodated in the paper feed cassette 3 to the image forming conveying path 2, a conveying path connecting these two paths is provided. This conveyance path is a vertical paper feed path 5 formed vertically near the left side wall of the image forming apparatus main body. Then, in order to discharge the sheet on which the image formation (transfer of the toner image) is completed to the sheet discharge tray 4 via the image forming conveyance path 2, the image forming apparatus main body serves as a conveyance path connecting the both paths. A paper discharge path 6 is vertically provided near the right side wall of the. Further, between the vertical paper feed path 5 and the paper discharge path 6, the sheets are connected to the respective conveyance paths and are fed again to the image formation conveyance path 2, and when the front and back surfaces of the sheet are reversed. An intermediate transport path 7 is provided.

The intermediate conveying path 7 is arranged in the space between the image forming conveying path 2 of the image forming section 1 and the sheet feeding cassette 3. Then, the vertical paper feed path 5 of the intermediate conveyance path 7
On the side, a path 7a that joins the image forming transport path 2 is formed in a curved shape, and on the side of the paper discharge path 6, the image forming transport path 2 is formed.
Similarly, the sheet is branched into a curved shape so that the sheet can be smoothly conveyed. Further, the conveyance paths are connected so that the front and back surfaces of the sheet are reversed from the intermediate conveyance path 7 and guided to the paper discharge path 6, and that portion is also formed in a curved shape. Therefore, the switching means 8 for branching to the respective conveyance paths and selectively guiding the same is provided on the paper discharge path 6 side of the intermediate conveyance path 7.

The switching means 8 selectively guides the sheet output through the image forming conveyance path 2 to the paper ejection path 6 or the intermediate conveyance path 7, and switches the sheet sent to the paper ejection path 6. Switching control is performed so that the sheet is guided back to the intermediate conveyance path 7 and the sheet guided to the intermediate conveyance path 7 is switched back to be guided to the discharge path 6. As a result, the front and back surfaces of the sheet can be reversed and discharged onto the discharge tray 4, and images can be formed on both sides of the sheet.

Next, the image forming section 1, the image forming transport path 2, the sheet feeding cassette 3 and the sheet discharging table 4 of the image forming apparatus body will be described in detail.

First, the image forming section 1 is for reproducing image data sent from the outside or an image processing apparatus such as a scanner as a visible image, and has a drum shape forming an image carrier at the center thereof. The photoconductor 11 is provided.
The photoconductor 11 is sensitive to light and is irradiated with digital light according to image data. For that purpose, a laser writing unit 9 which is an image writing unit forming a part of the image forming unit 1 is provided. The laser writing unit 9 irradiates a digital light image by a laser on the surface of the photoconductor 11 according to image data sent from a control unit (not shown). And Figure 1
As shown in FIG. 3, the laser writing unit 9 is arranged adjacent to the image forming unit 3 on the lower right side.

The laser writing unit 9 is well known, and is constituted by a semiconductor laser, various reflection mirrors and polygon mirrors, a plurality of lenses, and the like, and an image sent through the control unit. The semiconductor laser is controlled to be turned on and off in accordance with the data, and the laser light is scanned and irradiated in the rotation axis direction of the photoconductor 11 via various mirrors (including polygon mirrors) and lenses. . Therefore, the reflection mirror 10 is provided so as to face the photoconductor 11 and irradiate the laser light from the laser writing unit 9.

As well known in the art, the photoconductor 11 includes a charger 12 for uniformly charging the surface of the photoconductor to make the photoconductor sensitive to light, an exposure opening 13 for irradiating the laser beam,
A developing unit 14 for developing an electrostatic latent image according to image data formed after exposure, a toner image located in the image forming transport path 2 and electrostatically transferred to a sheet to which a toner image developed by the developing unit is appropriately sent. A transfer belt unit 15 for removing the toner, a cleaning unit 16 for removing the toner remaining on the surface of the photoconductor 11 after the transfer so that the photoconductor 11 can be repeatedly used again, and a charge removing unit 17 for removing the electric charge remaining on the photoconductor 11. The (process) means is arranged along the rotation direction of the photoconductor 11 indicated by the arrow A.

For example, the photoconductor 11 forming the image forming unit 1,
The charging device 12, the exposure opening 13, the developing device 14, and the cleaning device 16 may be integrally formed as a unit and can be replaced at the same time. Further, the developing means 14 may be formed as a separate unit so that the developing unit and the photoconductor unit can be individually replaced. This replacement is performed due to the toner running out of the developing unit, the life of the photoconductor unit, and the like. In the developing unit,
In some cases, when the toner runs out, the toner replenishing cartridge may be replaced or replenished without replacing the unit.

When image formation is started by the image forming section 1, the photoconductor 11 is rotationally driven in the direction A, and the charger 12 uniformly charges the surface of the photoconductor 11. Next, when the surface of the photoconductor 11 charged by the charger 12 reaches the exposure opening 13, the laser light from the laser writing unit 9 is irradiated through the folding mirror 10 to uniformly charge the surface of the photoconductor 11. The generated charge becomes an electrostatic latent image corresponding to the image data. Next, the formed electrostatic latent image faces the position of the developing means 14, whereby toner as a colorant is selectively adhered, and the toner is reproduced as a visible image. The visible image, that is, the toner image is electrostatically transferred onto a sheet that is electrostatically attracted to the surface of the transfer belt 15.

On the other hand, a part of the toner that has not been transferred remains on the surface of the photoconductor 11 after the transfer, and the residual toner is removed at the position of the cleaning means 16. Then, the electrostatic charge remaining on the photoconductor 11 is finally removed by the charge removing unit 17 from the photoconductor 11 from which the toner has been removed. In this case, a charge-removing lamp is used as the charge-removing unit 17, and the entire surface of the photoconductor 11 is illuminated with uniform light.
Therefore, the surface potential of the photoconductor 11 is set to a substantially uniform low potential so that the charging of the charger 12 by the image formation of the next image data becomes uniform. Such a process is continuously performed, and image data is sequentially reproduced as a visible image on a sheet, finished as a hard copy, and discharged onto the sheet discharge tray 4.

Next, various members arranged in the image forming transport path 2 will be described. In the image forming conveyance path 2, first, the sheet fed upstream from the sheet feeding cassette 3 through the vertical sheet feeding path 5 is temporarily stopped, and the sheet is formed in synchronization with the leading edge of the image on which the image is formed. A registration roller 20 is provided for feeding the image to the image position. This registration roller 2
In No. 0, the leading end of the sheet is stopped at the nip portion of the roller, so that the selection is aligned at the nip portion and the diagonal feeding is prevented at the same time.

The sheet fed through the registration roller 20 is controlled so that its leading end is aligned with the leading end of the image on the photoconductor 11 at the transfer position. And
The sheet is conveyed so as to be electrostatically held by the transfer belt means 15 provided in contact with the photoconductor 11 so as to come into contact with the photoconductor 11.

The transfer belt means 15 forms a part of the image forming section 1 and the image forming conveyance path 2, and an endless transfer belt 15a is stretched between the driving roller 18 and the driven roller 19. It is configured to hang.
The belt 15a is made of, for example, a dielectric material,
The registration roller 20 is charged by a charging unit (not shown).
The sheet sent via the sheet is electrostatically attracted and held, and is sent to an image forming position in which the sheet is opposed to the photoconductor 11.

The transfer belt 15a is arranged so that the driven roller 19 side is close to the photosensitive member 11. For example, if a predetermined transfer potential is applied to the driven roller 19, the belt 15a is charged. At the same time, the toner image on the photoconductor 11 can be transferred onto the sheet. It is also possible to provide a transfer electrode (including a roller or the like) on the back surface side of the belt 15a that is in contact with the photoconductor 11 and supply a transfer potential to the electrode to perform transfer.

Further, a fixing section 21 for fixing the toner image transferred on the sheet is provided on the downstream side of the transfer belt means 15 in the image forming conveying path 2. The fixing unit 21 has a conventionally well-known configuration, and includes a heat roller 22 formed by coating a surface of a metal pipe such as aluminum with a heat-resistant release resin, and a silicon rubber around a metal cored bar. A pressure roller 23 formed by coating a heat-resistant elastic layer such as a heat roller, a heater lamp 24 disposed inside the heat roller to supply heat, and a heat roller surface for detecting the heat roller surface temperature. It is composed of a temperature detector 25 such as a thermistor arranged in contact with the outer circumference.

The fixing section 21 includes a peeling claw 26 arranged in contact with the outer periphery of the heat roller or the pressure roller for peeling the sheet from the heat roller or the pressure roller as required, and the surface of the pressure roller. Cleaning roller 2 provided in pressure contact with the surface of a pressure roller for cleaning
7, and a pressure means (not shown) for pressing the heat roller and the pressure roller into contact with each other with a predetermined pressure.

Therefore, the unfixed toner image on the sheet formed by the image forming section 1 is melted by the sheet being conveyed through the transfer belt 11 and being sent to the fixing section 21. Then, the sheet is pressed and heat-fixed. That is, when the sheet passes between the heat roller 22 and the pressure roller 23, heat and pressure are applied, and the unfixed toner is fixed on the sheet. After that, the peeling nail 26
Thus, the sheet is peeled off from the heat roller 22.

The cleaning roller 27 is arranged downstream of the pressure roller 23 in the sheet conveying direction. This is because the sheet has the transfer belt 1 on the upper surface side in the gravity direction.
It is adsorbed and conveyed by 5 and delivered to the fixing unit 21. At this time, the heat roller 22 and the pressure roller 23 are brought into pressure contact with each other in a state where the leading edge of the sheet becomes free and the leading edge side hangs down due to the action of gravity, or in a state where the leading edge of the sheet is largely curved in a direction orthogonal to the transport direction. It prevents the sheet from being wrinkled and broken by being caught in the nip. For that purpose, the downstream end of the transfer belt 11 in the transport direction and the nip portion of the fixing unit 21 are made as close as possible to each other, thereby eliminating the above-mentioned problems.

The fixed sheet sent out from the fixing section 21 is further conveyed through a conveying roller 28 provided on the downstream side of the image forming conveying path 2, and is curved and connected to the above-described sheet discharging path 6. It is sent out to the paper discharge path 6 by the conveyance roller 29 provided in the portion to be discharged.

Subsequently, in the sheet feeding cassette 3 constituting the sheet accommodating portion, a mounting table 31 rotatably provided on the accommodating housing 30 for the sheet P holds the sheet P at a predetermined position by a biasing means 32 such as a spring. It is configured to surface.
A sheet feeding roller 33 that faces the uppermost portion of the sheet P to be floated and is in contact with and feeds the sheet is provided so as to correspond to the leading end of the sheet in the sheet feeding direction of the sheet feeding cassette 3. Further, on the downstream side of the paper feed roller 33, there is provided a feed roller 34 for feeding the sheet P fed by the paper feed roller 33 to the vertical paper feed path 5 connected to the image forming transport path 2. Has been.

Although not shown, the accommodating housing 30 is provided with a separating claw corresponding to the leading end of the sheet. The separating claw is for feeding one sheet P, is provided corresponding to both ends of the leading end of the sheet, is rotatably provided with respect to the storage housing 30, and is provided on the uppermost sheet. It is supposed to be placed under its own weight. Therefore, the leading end of the sheet sent out by the sheet feeding roller 33 is largely curved when it goes over the separating claw, and the uppermost sheet and the lower sheet are separated from each other, so that one sheet can be fed.

As another means for feeding one sheet when the above-mentioned separation claw is not provided, the feeding roller 34 is rotationally driven, for example, in the direction of feeding the sheet to the vertical sheet feeding path 5. And a separating roller that separates the double-fed lower sheet from the uppermost sheet and is driven in the direction to return the sheet so that one sheet can be fed. As a result, it is possible to prevent double feeding at the position of the feeding roller 34 and feed only the uppermost sheet P.

The sheets P stored in the paper feed cassette 3 are
When it is sent out through the paper feed roller 33 and the feed roller 34 as described above, it is sequentially sent to the vertical paper feed path 5. The vertical feed path 5 is provided with a conveyance roller 35 for feeding the fed sheet to the registration roller 20 located in the image formation conveyance path 2. As a result, the sheet P is sent to the registration roller 20 via the carrying roller 35, and image formation is performed via the image forming carrying path 2.

Here, a sheet is fed from the uppermost sheet stored in the paper feed cassette 3 to the image forming transport path 2 through the vertical paper feed path 5, and the upper and lower sides of the vertical paper feed path 5 are fed. It is possible to reduce the curvature including the curved portion and increase the radius of the curved portion. Therefore, the sheet transportability is reduced, and the occurrence rate of jams such as sheet jams can be reduced. This point will be described in detail below.

Then, the output sheet on which the above-mentioned image formation, that is, the hard copy in which the visible image corresponding to the image data is reproduced is completed, is positioned on the top of the image forming apparatus and is transferred to the discharge tray 4 exposed to the outside. And discharged. A sheet discharge roller 40 is provided at a sheet discharge port of the sheet discharge tray 4. The sheet discharge port is provided at the most downstream position of the sheet discharge path 6, and the sheet discharge roller 40 is provided corresponding to the position to discharge the sheet to the sheet discharge tray 4.

The discharge table 4 is provided in an inclined state so that the portion of the discharge surface facing the discharge roller 40 is at the lower position. Therefore, the discharged sheet is aligned with the regulation end 41 provided at the lower position at the rear end, and the stacking property and the like are improved. Further, a transport roller 42 is provided in the paper discharge path 6 in order to feed the hard-copy completed sheet to the paper discharge roller 40 through the paper discharge path 6.

Although the image forming apparatus shown in FIG. 1 is provided with the intermediate conveyance path 7, such an intermediate conveyance path 7 is not necessary in the present invention. That is, at least the sheet from the image-forming conveyance path 2 is directly fed to the sheet ejection stand 4
In order to discharge the sheet to the sheet, the sheet discharge path 6 that connects the image forming transport path 2 and the sheet discharge table 4 may be provided. However, the intermediate conveying path 7 is provided when images are formed on both sides of the sheet and when the image forming surfaces of the sheet are reversed and discharged.

In the intermediate conveyance path 7, the conveyance rollers 4 are provided for feeding the sheet to the joint flow path 7a of the image formation conveyance path 2.
3, 44, 45 are provided. Here, the transport roller 45 is provided so as to be capable of forward and reverse rotation driving, and enables switchback transport of the sheet. Also, the discharge path 6
Similarly, the conveyance roller 42 provided in the above can also be driven to rotate in the forward and reverse directions, thereby enabling switchback conveyance. This makes it possible to reversely discharge the sheet and form images on both sides of the sheet.

In the image forming apparatus configured as described above, the image formation on the sheet and the image formation on both sides are described below.
Further, the control of the discharge of the sheet onto the discharge tray 4 will be described. In order to realize this, the configuration of the switching unit 8 that performs sheet guide control by selectively passing through the image forming transport path 2, the paper discharge path 6, and the intermediate transport path 7 will be described in detail.

The switching means 8 is constructed by providing switching gates 81, 82 and 83 corresponding to the positions of the respective conveying paths 2, 6 and 7, as shown in detail in FIG. ing. The switching gate 81 is movably provided at a position shown by a solid line and a position shown by a broken line as shown in the drawing.

Therefore, when the switching gate 81 is located at the position shown by the broken line, the sheet is conveyed toward the sheet discharge port by the conveying roller 42 of the sheet discharging path 6 via the conveying roller 29. In this case, the switching gate 83 is moved to the position shown by the solid line, and the transport roller 42 is rotationally driven in the arrow C direction. Then, when the sheet is discharged by the transport roller 42, the transport roller 42 is driven and controlled as it is, and the image surface formed by the image forming unit 1 is discharged upward to the sheet discharge tray 4. Therefore, in the state where the image is formed from the last page as the image data, by ejecting the sheet with the image side facing up, the page order of the output sheets ejected on the sheet ejection tray 4 is aligned.

On the other hand, in the case of the discharge processing with the image surface facing down, the switching gate 81 is moved to the position shown by the solid line. Then, the sheet is conveyed by the conveying roller 29,
It is branched and guided to the intermediate conveyance path 7. At this time, the switching gate 82 is moved to the position shown by the broken line on the side of the intermediate conveyance path 7, and the conveyance roller 45 is rotationally driven in the direction of arrow A. Therefore, the sheet is guided by the switching gate 82 and sent to the intermediate conveyance path 7 via the conveyance rollers 45. Then, when the trailing edge of the sheet passes through the switching gate 82, the state is detected by the detection sensor.

Therefore, the switching gate 8 of the transport roller 45
An optical detection sensor 46 is arranged on the side opposite to 2. As a result, the sheet is conveyed to the intermediate conveyance path 7 via the conveyance rollers 45, and when the trailing end of the sheet passes the optical detection sensor 46, the state is detected. Therefore, in response to the detection, after the driving of the conveyance roller 45 is stopped, the conveyance roller 45 is reversely rotated in the arrow A direction. Then, the sheet is switchback conveyed. At this time, at the same time, the switching gate 82 is movably switched to the position indicated by the solid line, and the switching gate 83 is moved to the position indicated by the broken line, so that the transport roller 42 is moved.
Is driven to rotate in the u direction.

Therefore, the sheet is guided from the intermediate conveying path 7 to the sheet discharging path 6 with the rear end being the top, and is sandwiched by the conveying rollers 42 and discharged to the sheet discharging table 4. At this time, the image on the sheet is output to the paper output tray 4 in an inverted state.

When forming images on both sides of the sheet, the switching gate 81 is movably switched to the position shown by the broken line. The switching gate 83 is movably switched to the position indicated by the solid line. The sheet on which the image formation is completed on one side is conveyed along the sheet discharge path 6 via the conveying rollers 29 and 42. Then, when the trailing edge of the sheet passes through the switching gate 83, the state is detected by the detection sensor. Therefore, an optical detection sensor 47 is provided on the side of the transport roller 47 facing the switching gate 82.
The trailing edge has been detected.

Therefore, the trailing edge of the sheet is the detection sensor 4
When the position 7 is passed, it is detected. Then, in response to the detection, the transport roller 42 is stopped,
It is reversely rotated in the direction of arrow d. At the same time, the switching gate 83 is moved to the position shown by the broken line, and the switching gate 82
In Fig. 5, the movable switching control is performed to the position shown by the solid line. Therefore, the sheet is switch-back-transported by the transport rollers 42 and sent to the intermediate transport path 7. The transport roller 45 on the side of the intermediate transport path 7 is rotationally driven in the A direction and is again transported to the image-forming transport path 2 via the joint flow path 7a.
At this time, the sheet is conveyed to the image forming position with its image forming surface facing upward, that is, in the state where it is adsorbed on the surface of the belt 15a of the transfer belt means 15, so that the sheet is moved to the surface opposite to the image surface previously formed on the sheet. Image formation is performed.

The transport rollers 42 and 45 are provided such that they can be driven to rotate in the forward and reverse directions. However, as long as the rotation can be transmitted by the motors of the same drive source,
By providing a clutch for forward / reverse rotation on each of them, drive control for forward / reverse rotation can be easily performed. Also,
When a dedicated drive motor is provided only for the conveying rollers 42 and 45, the motor can be easily controlled by controlling the forward and reverse rotation drive.

Next, the control operation for actually forming an image on the sheet and performing the discharging process will be described. In particular, a case will be described in which image data is transferred to the image forming apparatus in order from the first page to the last page, and image formation is performed in that order. This is a case where the image forming apparatus normally operates as a print mode or a facsimile mode when reproducing and outputting the image data transferred from the external device.

First, the operation of forming an image on one side of a sheet and discharging the sheet by aligning the sheets on the sheet discharge tray 4 in the page order will be described with reference to FIGS. 3 and 4.

When the main body of the image forming apparatus receives a command to start image formation on one side of the sheet, each switching gate 8 of the switching means 8 will be described.
The movement switching control of 1, 82, 83 is performed in the state shown in FIG. Further, the transport rollers 29, 42, 45 are rotationally driven in the arrow direction.

Therefore, as shown in FIG. 4, the sheets P are sequentially transferred from the top of the sheet feeding cassette 3, which is a sheet storage section, one by one.
The sheets are fed one by one to the registration rollers 20 through the vertical sheet feeding path 5 via the sheet feeding roller 33 and the feeding roller 34.
The mark indicated on the sheet P indicates the image forming surface side, and indicates the leading edge of the sheet at the time of feeding.

On the sheet P fed by the registration rollers 20 to the image forming position facing the image forming section 3 of the image forming conveying path 2, the toner image formed on the photoconductor 11 rotated in the arrow direction is formed. The image is transferred by the action of the transfer belt unit 15 and is sent to the fixing unit 21. The toner image is fixed on the sheet passing through the fixing unit 21, and the image forming surface is reversed through the switching unit 8 to be discharged.

That is, as shown in FIG. 4, after the fixing process is completed, the sheet is once conveyed by the conveying roller 29,
It is guided to the switching gates 81 and 82 and is transported to the intermediate transport path 7 via the transport rollers 45 of the intermediate transport path 7. Then, in the state of FIG. 3A, when the trailing edge of the sheet P passes the detection sensor 46, that state is detected. In response to this detection, only the switching gate 82 is movably switched to the state shown in FIG. 3B, and at the same time, the transport roller 45 is reversely driven.

Therefore, the sheet P is conveyed from the intermediate conveyance path 7 with the image surface thereof facing upward as shown in FIG. 4, and the rear end of the sheet P is sandwiched by the conveyance rollers 45.
Switchback conveyance is performed at 5, and switching gates 82 and 83
And is guided to the conveyance roller 42 side. Therefore, the image surface of the sheet P is reversed, and the sheet P is discharged onto the sheet discharge tray 4 via the sheet discharge path 6 and the sheet discharge roller 40 with the image surface down.

The above-described operation is sequentially repeated, and the order image is formed from the first page of the image data, and the second page and the third page are formed.
Ejection processing is performed in the order of page and last page. As a result, as shown in FIG. 4, the copied sheets P whose page order is aligned are accumulated on the paper output tray 4.

Next, the operation of forming an image on both sides of the sheet will be described with reference to FIGS. 5 and 6. Each of the gates 81, 82 of the switching means 8 is instructed by the start command of the image forming operation.
83 is switch-controlled to the state shown in FIG.
At this time, the transport rollers 29, 42, 45 are rotationally driven in the directions shown in the figure.

Therefore, as shown in FIG. 6, the sheets P are sequentially fed from the top of the sheet feeding cassette 3 which is the sheet storage portion.
The sheets are fed one by one to the registration rollers 20 through the vertical sheet feeding path 5 via the sheet feeding roller 33 and the feeding roller 34.
The mark shown on the sheet P indicates the surface side on which an image is first formed, and also indicates the leading end side of the sheet to be fed.

On the sheet P fed by the registration rollers 20 to the image forming position facing the image forming section 3 of the image forming conveying path 2, the toner image formed on the photoconductor 11 rotated in the arrow direction is formed. The image is transferred by the transfer action of the transfer belt unit 15 and is sent to the fixing unit 21. The transfer toner image is fixed on the sheet passing through the fixing unit 21, and the sheet is conveyed to the paper discharge path 6 in the same posture via the switching gates 81 and 83 of the switching unit 8.

That is, as shown in FIG. 6, after the fixing process is completed, the sheet is once conveyed by the conveying roller 29,
The sheet is conveyed by the conveying roller 42 in the sheet discharge path 6. Then, when the trailing edge of the sheet P passes through the detection sensor 47 as shown in FIG. 5A, the state is detected. In response to this detection, the switching gates 82 and 83 are movably controlled to the state shown in FIG. 5B, and at the same time, the transport roller 42 is reversely rotated.

Therefore, the sheet P is switchback-transported by the transport rollers 42 and is transported to the intermediate transport path 7 with the already formed image surface facing down. And
In order to transfer the reproduced image according to the image data of the next page, the image is conveyed again to the registration roller 20 located in the image forming conveyance path 2. In this case, the sheet P is conveyed along the image forming conveyance path 2 such that the surface opposite to the previously formed image forming surface comes into contact with the photoconductor 11 of the image forming unit 1.

As described above, the sheet P on which images have been formed on both sides of the sheet P is sent to the conveying roller 29 via the fixing unit 21. Here, if it is detected that the rear end of the sheet P has been conveyed through the intermediate conveyance path 7 and has passed the position of the detection sensor 46, then the switching gates 82 and 83 are in the original state, that is, FIG. ), And at the same time, the transport roller 42 is also driven to rotate normally.

Then, the sheet P is guided to the sheet discharge path 3 by the conveying roller 29, and is discharged by the conveying roller 42 in a state where both sides of the sheet P are image-formed on the sheet discharging table 4. At this time, a state in which an image is formed on the opposite surface of the sheet P is indicated by a triangle mark. The discharged sheet P is discharged so that the first (odd number) page on which the image is formed first faces the discharge tray 4.

The above-described operation is sequentially repeated, and the order image is formed from the first page of the image data, and the second page and the third page are formed.
Ejection processing is performed in the order of page and last page. As a result, as shown in FIG. 6, the copied sheets P whose page order is aligned are accumulated on the sheet discharge tray 4.

In the image formation on both sides, when the image formation on both sides of the previous sheet P is completed, the next sheet P is sent to the registration roller 20. In order to speed up the feeding, the sheet P is advanced to the position of the conveying roller 35 of the vertical sheet feeding path 5 shown in FIG. 1 and stopped. Then, when the trailing edge of the preceding sheet P during double-sided formation passes through the registration roller 21, the feeding to the registration roller 21 is started. As a result, the copying speed for forming images on both sides can be increased.

(Characteristics of the constitution of the present invention and its function and effect)
As described above, the image forming apparatus of the present invention, regardless of whether image formation is performed on one side or both sides of the sheet P, the image forming unit 1 and the image writing unit that constitutes a part of the image forming unit are provided at the bottom. A laser writing unit 9 as a means is provided, an image forming conveyance path 2 for forming a visible image by the toner formed by the image forming unit 1 on a sheet is provided on the upper portion thereof, and a sheet accommodating portion is provided on the upper portion thereof. The paper cassette 3 and the paper discharge table 4 are sequentially arranged so as to be stacked on top of the image forming apparatus.

As a result, when the sheet cassette 3 can accommodate the maximum size of sheets, the sheet ejection tray 4
Can sufficiently secure a space corresponding to it, and therefore, there is no portion where the paper ejection tray 4 projects from the main body of the image forming apparatus, and the occupied floor area for installing the image forming apparatus can be minimized. Further, when images are formed on both sides of the sheet P, a sufficient length corresponding to the maximum size can be ensured even in the intermediate conveyance path 7, and moreover, between the paper feed cassette 3 and the image formation conveyance path 2. Can be installed in
There is no need to secure a large space, and there is no need to upsize the entire device.

Further, as for the completed product handling work which is most frequently performed by the user, since the discharge table 4 is provided at the top, the work is simplified and there is no problem.

Further, since the fixing section 21 is provided in the image forming transporting path 2 and the laser writing unit 9 which constitutes a part of the image forming section 3 disposed thereunder is provided, the fixing section 21 is provided. It is possible to greatly suppress the heat, which is generated at 21 and tends to rise, from being transmitted to the laser writing unit 9.
In this case, a space portion 36 exposed to the atmosphere (air) outside the image forming apparatus may be interposed between the laser writing unit 9 and the fixing portion 21. This allows
It is possible to almost completely block the heat generated in the fixing portion 21 from being transmitted to the laser writing unit 9, and at the same time, the space portion 36 can be sufficiently secured.

As described above, the laser writing unit 9 is not provided at the lowermost position so as to overlap the image forming unit 1, but is adjacent to the image forming unit 1 in the horizontal direction. Even when it is arranged at 1, the fixing unit 21 can be positioned below the fixing unit 21, and the fear of causing a defect due to an increase in heat is eliminated. At the same time, since the laser writing unit 9 is arranged in parallel with the image forming unit 1, it is possible to prevent the height direction of the image forming apparatus from increasing.

Next, a second embodiment of the present invention that enables simplification of work inside the image forming apparatus will be described.

(Second Embodiment of the Present Invention) In this embodiment, in the image forming apparatus shown in FIG. 1, the inside of the image forming apparatus, for example, replenishment of sheets, jam processing, and replacement of the image forming unit 1, This is a configuration for facilitating maintenance work such as cleaning.

(Embodiment for facilitating sheet replenishment work)
A practical example for easily performing the work of replenishing the sheet to the sheet feeding cassette 3 which is the sheet accommodating portion will be described below.

The paper discharge tray 4 located at the top of the image forming apparatus main body is rotatably provided as shown in FIG. In order to enable this rotation, in FIG. 1, the regulation end 41 side of the paper discharge table 4 is supported rotatably around a rotation fulcrum shaft 48 on the image forming apparatus main body side. The discharge tray 4 on the opposite side of the rotation fulcrum shaft 48 is in contact with and supported by the top portion 52 of one side wall (exterior) 51 on the vertical sheet feeding path 5 side of the image forming apparatus, as shown in FIG. It has become so.

As shown in FIG. 1, a recess 53 is formed in the vicinity of the apex 52 of the one side wall 51, and one end of the paper ejection tray 4 supported by the apex 52, that is, the side opposite to the fulcrum shaft 48. The user's hand is inserted and the end of the is lifted to facilitate the turning operation.

Therefore, in order to store the sheet P in the sheet feeding cassette 3, that is, to replenish the sheet, the end portion of the sheet discharge tray 4 is lifted by the user, and as shown in FIG.
Is rotated around. As a result, the paper feed cassette 3
The upper portion of the casing 30 is largely opened, and the sheet replenishing work becomes easy.

In this case, one of the sheet feed roller 33 and the sheet feed roller 34 provided corresponding to the sheet feed cassette 3 is provided on the back side of the sheet discharge table 4. As a result, the entire upper surface side of the housing 30 of the paper feed cassette 3 is opened, so that the sheet replenishment work becomes easier. Moreover, by separating the feeding roller 34, when the sheet fed from the sheet feeding cassette 3 is jammed at that position, the jam processing operation is simplified.

It should be noted that in FIGS. 1 and 7, the cover 49 provided on the side of the paper discharge roller 40 of the paper discharge table 4 is the discharge roller 40.
Covers the paper and protects it, while at the same time the user
Prevent various obstacles caused by touching. The cover 49 is also rotated at the same time as the rotation of the paper discharge table 4. Further, the cover 49 is conveyed through the paper discharge path 6, and when switchback conveyance is performed in the paper discharge path 6, when the leading edge of the sheet P is output via the paper discharge roller 40, the user pulls it out randomly. It can also serve to prevent defects at the same time. That is, it is possible to hide the state in which the leading edge of the sheet is projected to the paper ejection tray 4 for double-sided image formation.

Also, in the opening operation of the paper discharge table 4,
Since the rotation fulcrum shaft 48 is provided on the side of the regulating end 41 that regulates the trailing end of the sheet, even if the discharged sheet P is present on the sheet ejection tray 4, the trailing end of the sheet is regulated by the regulating end 41. It is possible to prevent it from being regulated and falling.

Further, the paper discharge table 4 also serves as the upper lid of the housing 30 of the paper feed cassette 3 described above. That is, the back surface side of the paper ejection tray 4 is provided with the housing 30 when the paper ejection tray 4 is closed.
Is configured to cover the upper surface side of the.

(Embodiment for facilitating jam clearance work)
Since the sheet jam occurs in the sheet conveying path, each conveying path may be opened.

Therefore, in the embodiment of the present invention,
In FIG. 1, the entire paper feed cassette 3 is rotatably provided together with the paper discharge tray 4. The paper feed cassette 3 is provided so as to be rotatable around a rotation fulcrum shaft 48, similarly to the paper discharge table 4. Then, the bottom of the housing 30 at the end opposite to the rotation fulcrum shaft 48 of the sheet feeding cassette 3 is supported at a stepped position formed in a part of the guide member 54 forming the vertical sheet feeding path 5. It is configured to be.

The paper feed cassette 3 can be simultaneously rotated by the rotation operation of the paper discharge tray 4. That is,
When the paper feed cassette 3 is coupled via a lock mechanism as shown and only the paper discharge tray 4 is opened, the locked state of the lock mechanism is released. Then, when they are simultaneously rotated, they are kept in a locked state, and when the paper ejection tray 4 is opened, they are simultaneously rotated around the fulcrum shaft 48.

Therefore, by opening the paper discharge tray 4 and opening the paper feed cassettes 3 individually or simultaneously, the intermediate conveyance path 7 can be opened as shown in FIG. Therefore, if the upper guide plate 71 forming the intermediate conveyance path 7 and the like is provided so as to be openable, the work of removing the sheet jammed at that position becomes easy.

In the vertical paper feed path 5, one side wall 51
Is rotatably provided around the rotation fulcrum shaft 55. And
A guide member 56 is provided opposite to the guide member 54 for forming the vertical sheet feeding path 5 integrally fixed to the side wall 51. With this, when the one side wall 51 is opened,
As shown in FIG. 8, the vertical sheet feeding path 5 is opened at the same time, and the sheet jammed at that position can be easily removed.

In this case, if the guide member 56 is also formed so as to form the merging flow path 7a that joins the image forming conveyance path 2 of the intermediate conveyance path 7, as shown in FIG.
The downstream portion and the upstream portion of the image forming transporting path 2 are opened together, and the jam sheet removing operation at that position can be easily performed.

Further, if the paper feed cassette 3 is opened as shown in FIG. 8, the paper discharge path 6 on the back side facing the one side wall 51 can also be opened, so that the jam sheet can be easily removed at that position. become.

Here, the guide member 54 is provided so as to be positioned on the image forming apparatus main body side, but if it is provided on the paper feed cassette 3 side, it is opened by the opening operation of the paper feed cassette 3. To be done. Therefore, the guide member 54
Since the vertical sheet feeding path 5 formed in 1 and the merging portion 7a on the downstream side of the intermediate conveying path 7 are also opened together, the jam processing of the sheet becomes easy.

If the conveying rollers 35 provided in the vertical paper feed path 5 are provided on the guide member 54 and the guide member 56 side, respectively, when the vertical paper feed path 5 is opened.
Since the rollers are separated, the sheet jam processing operation is further facilitated.

On the other hand, when the sheet is jammed at the image forming position of the image forming conveying path 2 or at the fixing section 21 side, it is necessary to open the image forming conveying path 2. Therefore, the transfer belt means 15 and the upper roller of the registration roller 20 are supported in FIG.
The support member 72 shown in is provided so as to be rotatable around the rotation fulcrum shaft 73. In particular, the support member 72 also supports one guide member forming the intermediate conveyance path 7 at the same time.

Therefore, as shown in FIG.
Is separately opened together with the above-described paper discharge table 4 and the paper feed cassette 3, so that the image forming transport path 2 formed by the transfer belt means 15 and the like is opened. As a result, the photoconductor 1
The image forming position and the like facing 1 are opened, and the work of removing the sheet jammed at the position becomes easy. Further, in the state shown in FIG. 9, in conjunction with the rotation operation of the support member 72,
At the same time, the heat roller 22 and the pressure roller 2 of the fixing unit 21
If pressure 3 is configured to be released, the roller 2
It becomes easier to remove the jammed sheet sandwiched between the Nos. 2 and 23.

Further, as shown in FIG. 9, by opening the image forming transporting path 2, maintenance work for maintaining the print function of the image forming apparatus such as replacement and cleaning of the image forming unit 1 can be easily performed. become. For example, if part or all of the image forming unit 1 is made into a unit due to the life and the like and each unit is detachable, it is possible to very easily replace them and partially clean them.

It should be noted that, in FIG. 8, if one guide plate 71, etc. forming the intermediate conveying path 7 is supported on the back surface of the sheet feeding cassette 3 side, the sheet feeding cassette 3 can be rotated in response to the rotation operation. Thus, the intermediate conveyance path 7 can be opened. Therefore, it becomes easy to remove the jam sheet at that position.

Further, when the intermediate conveyance path 7 is opened and the jammed sheet is removed, it is not easy to remove the jammed sheet if the trailing edge of the sheet is held by the fixing section 21. Therefore, normally, if the rollers of the fixing unit 21 can be manually driven in the sheet conveying direction,
It can be easily removed by manual operation. However, if the side plate of the image forming apparatus, that is, the front side in FIG. 8, cannot be opened, the fixing unit 21 cannot be manually rotated. Therefore, the pressure state of the pressure unit of the fixing unit 21 is reduced with the sheet feeding cassette 3 opened. Thereby, the sheet can be pulled out. Further, in order to prevent the unfixed toner from adhering to the heat roller or the like without completely releasing the pressure, the pressure is maintained to such an extent that the unfixed toner can be fixed.

(Another Embodiment of the Present Invention) In the above description, the image forming section 1, the image forming conveying path 2, the intermediate conveying path 7 provided as necessary, the sheet feeding cassette 3, and the sheet discharging. When the bases 4 are sequentially stacked and arranged, each of them is arranged in a horizontal state. Therefore, in order to secure a large open space, it is necessary to increase the rotation angle of the paper ejection tray 4.

Therefore, the paper feed cassette 3 including the paper ejection stand 4 is also included.
It is possible to secure a large open space and improve various workability of the user without increasing the rotation angle of the above.

Therefore, the image forming apparatus may be constructed as shown in FIG. That is, the image forming unit 1, the image forming conveyance path 2, the sheet feeding cassette 3, and the like are arranged from the horizontal state to the upper inclined state. In particular, the sheet receiving surface of the sheet discharge tray 4 is provided in a horizontal state, but the sheet trailing edge may be inclined downward as shown in FIG.

Further, the rotation fulcrum shafts 48 and 73 of the supporting member 72 for supporting the paper discharge table 4, the paper feeding cassette 3, the transfer belt means 15 for forming the image forming transport path 2, and the like,
It is provided on the side with a high inclination and is configured to be rotatable.

In such a structure, as shown in FIG. 11, by rotating the paper discharge table 4, the open space on the front surface (left side in the drawing) of the image forming apparatus can be increased.
At this time, a large opening space can be secured even if the opening angle θ when the paper ejection tray 4 is rotated from the horizontal state (a) is smaller than the rotation angle shown in FIG. 7. Therefore, the work of replenishing the sheet to the sheet feeding cassette 3 can be easily performed. At the same time, by opening the one side wall 51 of the front surface, the conveyance path 5 and the like connected to the image formation conveyance path 2 can be opened, and the jam processing operation is also simplified.

Further, FIG. 12 shows a state in which the paper feed cassette 3 and the supporting member 72 are opened, and the image forming conveyance path 2, the intermediate conveyance path 7 and the like can be opened, and these conveyance paths can be opened. The removal work of the jam sheet becomes easy. This FIG.
According to the above, the one guide member 71 of the intermediate conveyance path 7, the conveyance rollers 43, 44, 45, etc. are configured to be supported by the back surface of the paper feed cassette 3 side, so that the paper feed cassette 3 is opened. As a result, the intermediate conveyance path 7 is opened at the same time. Further, one guide member 54 forming the vertical paper feed path 5 is also provided on the paper feed cassette 3 side. This allows
Jamming work becomes easier.

In FIG. 12, by rotating the support member 72 to open it, the image forming conveyance path 2 is opened, so that the jam processing operation becomes easy. At the same time, since the upper surface of the image forming unit 3 is opened, maintenance work of the image forming unit 3 can be easily performed.

In FIG. 12, the paper feed cassette 3 is opened and the support member 72 is not rotated, so that a jam process in the paper discharge path 6 for discharging the sheet to the paper discharge tray 4 is performed. The open space for is larger. Therefore, if the guide member 61 that forms the paper discharge path 6 and the roller side of the one transport roller 42 are supported on the paper feed cassette 3 side, the paper discharge path 6 can be opened at the same time. As a result, it becomes easy to remove the jammed sheet from the paper discharge path 6.

Here, the laser writing unit 9 is also arranged in an inclined manner in the state shown in FIG. 10, but the writing unit 9 is arranged horizontally on the bottom surface of the image forming apparatus main body as shown in FIG. Of course, you can do that. By arranging in this way, a sufficient space can be secured between the image forming conveyance path 2 and the fixing portion 21, and a sufficient space portion 36 for performing the division can be secured.

As shown in FIG. 12, when the paper discharge table 4, the paper feed cassette 3, and the support member 72 are rotated,
By making the opening angle small, the center of gravity of the image forming apparatus main body does not largely change in the opened state, and there is no risk of the image forming apparatus main body falling over.

(Other Embodiments of the Present Invention) In the image forming apparatus, the sheet is sent to the image forming position, the transfer of the toner image is completed, the image is formed after passing through the fixing portion and the image forming apparatus is completed. I try to discharge it. Therefore, as described above, the sheet is transported along the various transport paths provided. At this time, the probability of jamming increases if the transport direction is significantly changed.

For example, when a sheet is conveyed from the sheet feeding cassette 3 to the image forming conveying path 2, the conveying direction is largely changed by 180 °, and the vertical sheet feeding path 5 is provided to relay it. . At this time, the probability of jamming increases when the curvature at the position where the direction is changed is large, especially when the direction is rapidly changed by 180 °. Therefore, it is required to make the curvature when the direction is changed as small as possible (the radius of curvature is large), and it is necessary to secure a space for that.

In the image forming apparatus as shown in FIG. 1, when the sheet is conveyed from the sheet feeding cassette 3 to the image forming conveying path 2, the length of the vertical sheet feeding path 5 for relay is secured sufficiently large. If it is not possible, the curvature for changing the feeding direction by 180 ° becomes large, so that the radius (radius etc.) of the curved portion becomes small, so that the risk of jam occurrence becomes high.

Therefore, as shown in FIG. 1, when the uppermost sheet accommodated in the sheet feeding cassette 3 is fed and conveyed to the image forming conveying path 2, the length of the vertical sheet feeding path 5 is set to The height of the paper feed cassette 3 can be secured. Therefore, the length of the vertical paper feed path can be sufficiently taken, the curvature due to the change of the feeding direction in the whole can be made small, and the probability of jam occurrence can be made small.

Further, as shown in FIG. 13, when the sheet is fed from the lowermost one of the sheet feeding cassettes 3, the vertical sheet feeding path 5 corresponding to the height of the sheet feeding cassette 3 in FIG. Cannot be secured. However, if the intermediate conveying path 7 is interposed between the sheet feeding cassette 3 and the image forming conveying path 2, the conveying path 7 can sufficiently secure the vertical sheet feeding path 5. Therefore, it is possible to design the curvature for feeding from the lowermost accumulated sheet of the sheet feeding cassette 3 and sending it to the image forming transport path 2 to reduce the probability of jam occurrence.

In FIG. 13, when the sheet for double-sided copying is re-conveyed from the intermediate conveying path 7 to the image forming conveying path 2, it is sufficient to secure the conveying path of the joining portion (7a) alone. It is possible that you cannot. Therefore, the curvature when the sheet is sent to the image forming transport path 2 becomes large, and the probability of occurrence of sheet jam increases.

Therefore, in the case of performing double-sided copying, the conveyance path for sheet switchback conveyance is provided at the vertical merging section 7a.
And the reversing conveyance path 5 on one side and the bottom of the image forming unit 1.
7 is provided and is fed to the image forming transport path 2 via a transport roller 58 which is provided at the entrance of the transport path 57 and which can be driven in the forward and reverse directions. With such a configuration, it is possible to reduce the curvature of feeding the sheet to the image forming transport path 2 and prevent the occurrence of a jam.

That is, the sheet sent through the intermediate carrying path 7 is once sent to the reversing carrying path 57 without being sent to the image forming carrying path 3 as it is, and the rear end of the sheet is nipped by the carrying roller 58. Then, the sheet is switchback-conveyed, guided to the image forming conveyance path 2 through a switching means (not shown), and fed. In this case, when performing double-sided copying, the sheet passes through the fixing unit 21 and is directly sent to the intermediate conveyance path 7 without being sent to the paper discharge path 6. Then, as described above, the switchback conveyance is performed using the reversal conveyance path 57, and the image formation can be performed on the surface opposite to the image formation surface of the previously formed sheet.

When a sheet fed from the lower part of the sheet feeding cassette 3 is fed to the image forming conveying path 2 through the vertical sheet feeding path 5 and the curvature cannot be increased, the above-mentioned reversal is performed. It is also possible to once feed the fed sheet to the conveyance path 57, perform switchback conveyance, and then feed it to the image formation conveyance path 3.

Further, according to the image forming apparatus shown in FIG. 14, the means for transferring the toner image formed on the photoconductor 1 in the image forming unit 1 is the transfer belt means 1 as shown in FIG.
5 shows a structure in which a corona transfer device is provided without providing 5.

That is, the corona transfer device 15b which faces the photoconductor 11 at the image forming position and charges the back surface of the sheet to the polarity opposite to the polarity of the toner, and the static eliminator 15 for peeling adjacent to the corona transfer device 15b.
c is provided. Then, in order to feed the sheet separated from the photoconductor 11 to the fixing unit 21, air is sucked from the back surface of the sheet, and the sheet is sucked and conveyed by the conveyance belt 15d. Further, since the leading end of the sheet tends to hang down after peeling, a peeling claw 15e is provided corresponding to the photoconductor 11 and an air blowing portion 15f is provided to surely guide the leading end to the transport belt 15d. With such a configuration, the image forming transporting path 2 is provided at the upper position of the image forming section 1, and the sheet on which the toner image has been transferred can be sent to the fixing section 21.

Even with such a configuration, the required image can be formed on the sheet as in FIG. 1, and the formed sheet can be discharged to the sheet discharge table 4 located at the top of the image forming apparatus. However, as compared with the case where the transfer belt unit 15 as shown in FIG. 1 is provided, the configuration becomes complicated, but the transfer efficiency can be improved by performing the corona transfer.

As described above, in the image forming apparatus of the present invention, it is not necessary to pull out and project the discharge tray and the like, the sheet feeding cassette and the like from the main body of the image forming apparatus, so that the image forming apparatus is installed. Eliminating the need to increase the floor space occupied for installation.

Further, since the paper discharge table 4 is provided on the top of the image forming apparatus, even if the completed product handling work is most frequently performed, the processing can be easily performed. Further, in the next frequent sheet replenishment work, the work can be facilitated by opening the upper paper feed tray 4. In the sheet jam processing, which is frequently performed, the sheet feeding cassette 3 is also rotatably provided, so that the image forming transport path and the like located therebelow can be opened and the processing can be easily performed. Further, since the image forming unit 1 is opened at the same time, maintenance work can be easily performed. Therefore, the object of the present invention, that is, the workability and the like required by the user can be sufficiently satisfied.

In the description of the above-described embodiment of the present invention, the image forming unit 1 of the image forming apparatus has been described as an example of the electrophotographic system. However, the image forming unit 1 is not limited to the electrophotographic system, and it goes without saying that an image forming apparatus including an image forming unit using a thermal system or an inkjet system can be implemented in exactly the same manner.

[0150]

According to the image forming apparatus described above, the floor area occupied when the apparatus is installed can be minimized. For example, the installation space of the image forming apparatus can be used.

In addition, workability when the user directly works such as replenishment of sheets and the like, removal of jammed sheets and the like becomes easy.

Further, the maintenance work of the image forming unit for maintaining the function of forming an image on the sheet can be easily performed together.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a structure of an image forming apparatus for explaining a first embodiment according to the present invention.

FIG. 2 is an explanatory diagram for selectively switching control of each conveyance path for realizing a process of discharging an image-formed sheet and image formation on both sides of the sheet in the image forming apparatus shown in FIG.

FIG. 3 is a diagram illustrating an operation of inverting an image surface and performing a discharge process when an image is formed on one surface of the sheet in FIG. 1.

FIG. 4 is a schematic diagram showing a flow of a sheet when the sheet is conveyed through the respective conveying paths shown in FIG. 3 and an image is formed on one side of the sheet.

FIG. 5 is a diagram for explaining an operation of forming an image on both sides of the sheet in FIG. 1 and, at the same time, performing a discharge process when image formation on both sides is completed.

FIG. 6 is a schematic diagram showing a flow of sheets when images are formed on both sides of the sheet by being conveyed through the respective conveying paths shown in FIG.

FIG. 7 is a diagram showing an open state of a sheet discharge tray for receiving sheets to be discharged in order to explain an image forming apparatus according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a state in which a sheet storage unit is opened in order to facilitate a jam sheet removing operation in each conveyance path for explaining the second embodiment of the present invention.

FIG. 9 is a diagram illustrating a state in which an image forming conveyance path is open for explaining a second embodiment of the present invention.

FIG. 10 is a configuration diagram showing a structure of an image forming apparatus for explaining another embodiment of the present invention.

11 is a diagram showing a state in which the sheet discharge tray is opened when performing sheet replenishing work in the image forming apparatus shown in FIG.

FIG. 12 is a diagram showing a state in which each conveyance path is opened in order to easily perform a jam sheet removing operation in the image forming apparatus shown in FIG.

FIG. 13 is a configuration diagram for explaining an example of suppressing the occurrence of a sheet jam in the image forming apparatus of the present invention.

FIG. 14 is a diagram showing an actual example of another unit for transferring the toner image formed by the image forming unit constituting the image forming apparatus to the sheet in the image forming apparatus of the present invention.

[Explanation of symbols]

1 image forming unit (electrophotographic method) 2 image forming conveying path 3 paper feeding cassette (sheet accommodating unit) 4 paper ejection table (paper ejecting unit) 5 vertical paper feeding path (of paper feeding cassette and image forming conveying path) Relay transport path 6 Discharge path (relay transport path between the image transport path and the discharge tray) 7 Intermediate transport path 8 Switching means 9 Laser writing means 11 Photoconductor 15 Transfer belt means 20 Registration roller 21 Fixing section 29 Transport Roller 30 Sheet housing 33 Paper feed roller 34 Feed roller 48 Rotation fulcrum shaft 51 One side wall 54 Guide member 56 Guide member 71 Guide plate 72 Support member 73 Rotation fulcrum shaft

Continuation of front page (56) Reference JP-A-1-284867 (JP, A) JP-A-3-89367 (JP, A) JP-A-1-92135 (JP, A) JP-A-3-73971 (JP , A) JP 7-128921 (JP, A) JP 5-100507 (JP, A) JP 2-280172 (JP, A) JP 8-67355 (JP, A) JP 6-46191 (JP, A) JP-A-7-271273 (JP, A) Actually open 2-2352 (JP, U) Actually open 6-57647 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/00 550 G03G 21/16-21/18 B41J 29/00

Claims (2)

(57) [Claims] 1. An image forming conveyance path for conveying a sheet fed from a sheet accommodating section to an image forming position of an image forming section for forming an image, and a discharging section outside the apparatus after the image formation. In the image forming apparatus configured to perform the discharge processing to the sheet discharge unit, the sheet discharge unit is provided so as to be exposed at the top of the image forming apparatus, and a sheet storage unit that stores a sheet under the sheet discharge unit, An image forming conveyance path for conveying a sheet fed and fed from the sheet accommodating section to an image forming position of the image forming section, and an image forming section provided so that the image forming position is located in the image forming conveyance path. Are stacked in this order, and branched to a discharge path for discharging the sheet to the paper discharge section for image formation on both sides of the sheet, between the sheet storage section and the image forming transport path. provided Te leading to transport path for the image forming the intermediate conveyance path is interposed, the upper The sheet accommodating portion rotatably relative to the image forming apparatus main body
The intermediate transfer path is provided so that it can be opened, and
One guide that forms the above-mentioned intermediate conveyance path on the side of the container housing portion
An image forming apparatus having a member . 2. The image forming unit is configured by an electrophotographic method, includes a laser writing unit for image forming, and the laser writing unit is arranged in parallel adjacent to the image forming unit. the fixing unit for fixing the image on the sheet which is formed through the image forming unit in the conveying path for the image provided, fixing unit is the Le
The laser beam from the laser writing unit is placed on top of the laser writing unit to carry the image.
Irradiate from the side opposite to the image forming position of the image forming unit facing the feeding path, and further between the laser writing unit and the fixing unit,
The image forming apparatus according to claim 1, characterized in that by interposing a space portion communicating with the outside of the image forming apparatus.