JP6908153B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus such as a copier and a printer, and more particularly to an image forming apparatus to which a relay unit for processing paper discharged from the image forming apparatus and a post-processing apparatus can be attached.

Generally, in an image forming apparatus such as a copier or a printer, when the paper on which an image is formed is discharged to a paper ejection tray, the paper is ejected by sitting on the paper. This waist, also called corrugation, is formed in a wavy shape on the paper, and the top of this waveform extends in the paper transport direction (discharge direction) to form a streak. By ejecting the paper while sitting down in this way, the paper can be ejected to the output tray in a state where the curl and curl of the paper are removed.

However, in the conventional corrugation imparting / non-imparting switching means, when various types of post-processing devices are attached to the main body paper ejection section, a transport failure may occur inside the delivery section or the post-processing device. For example, when the transport path is bent in the aftertreatment device, when the corrugated paper invades, the sheet on the waist does not follow the transport path and a transport failure occurs.

As a configuration that makes the waist of the paper variable, there is already a configuration that switches the presence / absence of the waist and makes the waist strength variable by individually advancing and retreating the configuration that gives corrugation in the direction that intersects the paper surface. It is known (for example, Patent Document 1).

Patent Document 1 describes a plurality of waisting members provided at predetermined intervals in a direction orthogonal to the paper transport direction for the purpose of changing the position and strength of waisting on the discharged paper, and the plurality of waisting members. In the double-sided image forming process, which has a plurality of driving means for individually moving the waist member of the sheet in a direction intersecting the paper surface of the paper discharged by the discharge roll and forms an image on both sides of the paper, an image is formed on the first surface. When a part of the paper on which the is formed is discharged to the outside of the machine by the discharge roll, the plurality of waist members are selectively moved from the retracted position to the waist position under the first condition, and the second surface. When the paper on which the image is formed is ejected to the outside of the machine by the ejection roll, the plurality of waist members are selectively moved from the retracted position to the waisted position under the second condition different from the first condition. A configuration of an image forming apparatus including a control means for controlling the plurality of drive means so as to be moved is disclosed.

As described above, in the image forming apparatus described in Patent Document 1, when an image is formed on both sides of a paper, a waist member is used depending on whether the image is formed on the first surface or the second surface. By selectively moving the position of, the position and strength of sitting on the ejected paper can be changed.

However, in a configuration in which the corrugation granting member is automatically advanced and retreated, it is possible to make the presence or absence of the waist variable, but the configuration becomes complicated and the space required for installing the corrugation granting member increases, resulting in cost. There was a problem of uploading.

In addition, instead of advancing and retreating the corrugation imparting member as a configuration in which the presence or absence of the waist is variable, the tubular member is attached to and detached from the recess provided in the roller shaft on the inner diameter side of the kick-out portion for waisting. It is disclosed (for example, Patent Document 2). According to the configuration described in Patent Document 2, it is possible to switch between the presence and absence of the waist only by attaching and detaching the tubular member, and it is not necessary to take a large space for the corrugation imparting member in the image forming apparatus.

However, in the configuration described in Patent Document 2, the roller shaft is fixed to the main body, and when the tubular member is attached to or detached from the recess, the retaining ring previously attached to the roller shaft is removed for each kick-out portion. It was necessary to slide the tubular member along the roller shaft, position the tubular member, and then attach the retaining ring to the roller shaft, and it was not always easy to attach and detach the tubular member.

The present invention has been made to solve such a problem, and by changing the seating conditions according to the paper transport path after the paper ejection section, paper transport defects are prevented and the space of the device is saved. At the same time, the purpose is to improve the workability of attaching and detaching the paper ejection roller and the roller holder of the paper ejection unit.

In order to achieve the above object, the image forming apparatus according to the present invention transfers the image formed by the image forming portion onto the paper, and then feeds the image to the fixing device and the fixing device to fix the image on the paper. In an image forming apparatus having a setting means for setting the type of the paper to be printed, the downstream side of the fixing device and the upstream side of the branch member for switching between a path for discharging the paper to the outside of the image forming apparatus and a double-sided inversion path. A transfer auxiliary roller pair and a guide member for guiding the paper discharged from the transfer auxiliary roller pair immediately after the transfer auxiliary roller pair are provided, and the guide member comes into contact with the paper to cause the transfer auxiliary roller pair. To a first position where the angle formed by the paper discharged from the paper and the guide member is changed, and to a second position where the angle formed by the paper discharged from the transport auxiliary roller pair and the guide member is not changed. It has a movable driving means, and at the time of double-sided printing on the paper, the guide member is arranged at the second position regardless of the type of the paper, and the guide member drives the transport auxiliary roller pair. It is characterized in that it is rotatably supported at a position coaxial with the roller shaft on the side and is movably configured to move to the first position and the second position by rotating and moving.

According to the present invention, the paper ejection failure is prevented by changing the seating conditions according to the paper conveying path after the paper ejection portion, and the space saving of the apparatus is realized, and the paper ejection roller of the paper ejection portion and the paper ejection portion The workability of attaching and detaching the roller holder can be improved.

It is sectional drawing which shows the schematic structure of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a perspective view which shows the image reading part of the image forming apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the curl correction mechanism and the fixing apparatus of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a perspective view of the paper ejection part of the image forming apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the paper discharge part of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a front view of the paper ejection roller of the image forming apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the paper ejection roller of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a front view of the paper ejection roller of the image forming apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the paper ejection roller of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the assembly of the paper ejection roller to the roller holder of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the assembly to the paper ejection part of the paper ejection roller of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the assembly of the paper ejection roller to the roller holder of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the assembly of the paper ejection roller to the roller holder of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the assembly of the paper ejection roller to the roller holder of the image forming apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows the assembly of the paper ejection roller to the roller holder of the image forming apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the state which attached the relay unit to the image forming apparatus which concerns on 1st Embodiment of this invention. It is a perspective view of the state in which the relay unit and the post-processing apparatus are attached to the image forming apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the state in which the relay unit and the post-processing apparatus are attached to the image forming apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing of the state which provided the output tray in the image forming apparatus which concerns on 1st Embodiment of this invention. It is a figure explaining the position of the guide member in the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a figure explaining the position of the guide member in the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a figure explaining the position of the guide member and the branch member in each operation mode in the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the pressurization side separation transfer member of the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the positional relationship of the guide member of the image forming apparatus which concerns on 2nd Embodiment of this invention, and the transfer auxiliary roller pair. It is a figure which shows the relationship between the driving means of the image forming apparatus which concerns on 2nd Embodiment of this invention, and a guide member. It is a schematic diagram which shows the positional relationship between the guide member and the drive roller of the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the relationship between the driving means of the image forming apparatus which concerns on 2nd Embodiment of this invention, and a guide member. It is a figure which shows the relationship between the driving means of the image forming apparatus which concerns on 2nd Embodiment of this invention, and a guide member. It is a figure which shows the positional relationship of the guide member and the branch member of the image forming apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the position of the humidity detection means of the image forming apparatus which concerns on 3rd Embodiment of this invention. It is a figure which shows the position of the humidity detection means of the image forming apparatus which concerns on 3rd Embodiment of this invention. It is a schematic block diagram which shows the control structure of the image forming apparatus which concerns on 3rd Embodiment of this invention. It is a figure which compared the on-off relationship of the decal by the paper thickness and humidity of the image forming apparatus which concerns on 3rd Embodiment of this invention, and the other image forming apparatus at present. It is a processing flow diagram which shows the on-off control of the decal of the image forming apparatus which concerns on 3rd Embodiment of this invention.

First, with reference to FIG. 1, the overall configuration and operation of the image forming apparatus according to the embodiment of the present invention will be described.

(First Embodiment)
The image forming apparatus 1 shown in FIG. 1 is a color laser printer, and four image forming units 4Y, 4M, 4C, and 4K are provided in the center of the apparatus main body, and an image reading unit 40 is provided on the upper part of the apparatus main body. Is provided. The image forming unit A that forms an image on the paper P in the image forming apparatus 1 includes an image forming unit 4. Each image forming unit 4Y, 4M, 4C, 4K uses toners and developing agents of different colors of yellow (Y), magenta (M), cyan (C), and black (K) corresponding to the color separation components of the color image. It has the same structure except that it is housed.

Specifically, each image processing unit 4Y, 4M, 4C, and 4K is formed on the drum-shaped photoconductor 5 as a latent image carrier, the charging device 6 for charging the surface of the photoconductor 5, and the surface of the photoconductor 5. A developing device 7 for supplying toner, a cleaning device 8 for cleaning the surface of the photoconductor 5, and the like are provided. In FIG. 1, only the photoconductor 5, the charging device 6, the developing device 7, and the cleaning device 8 included in the black image forming unit 4K are designated by reference numerals, and the other image forming units 4Y, 4M, and 4C have reference numerals. The code is omitted.

Below each image forming unit 4Y, 4M, 4C, 4K, an exposure apparatus 9 for exposing the surface of the photoconductor 5 is arranged. The exposure apparatus 9 has a light source, a polygon mirror, an f−θ lens, a reflection mirror, and the like, and irradiates the surface of each photoconductor 5 with laser light based on the image data.

Further, a transfer device 3 is arranged above each image forming unit 4Y, 4M, 4C, and 4K. The transfer device 3 includes an intermediate transfer belt 30 as an intermediate transfer body, four primary transfer rollers 31 as primary transfer means, a secondary transfer roller 36 as a secondary transfer means, a secondary transfer backup roller 32, and the like. A cleaning backup roller 33, a tension roller 34, and a belt cleaning device 35 are provided.

The intermediate transfer belt 30 is an endless belt, and is stretched by a secondary transfer backup roller 32, a cleaning backup roller 33, and a tension roller 34. Here, by rotationally driving the secondary transfer backup roller 32, the intermediate transfer belt 30 orbits (rotates) in the direction indicated by the arrow in the figure.

Each of the four primary transfer rollers 31 forms an intermediate transfer nip by sandwiching an intermediate transfer belt 30 with each photoconductor 5. Further, a power supply is connected to each primary transfer roller 31, and a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to each primary transfer roller 31.

The secondary transfer roller 36 sandwiches the intermediate transfer belt 30 with the secondary transfer backup roller 32 to form a secondary transfer nip. Further, similarly to the primary transfer roller 31, a power supply is also connected to the secondary transfer roller 36, and a predetermined DC voltage (DC) and / or AC voltage (AC) is applied to the secondary transfer roller 36. It has become like.

The belt cleaning device 35 has a cleaning brush and a cleaning blade arranged so as to come into contact with the intermediate transfer belt 30. The waste toner collected by the belt cleaning device 35 is stored in the waste toner container via the waste toner transfer hose.

A bottle accommodating portion 2 is provided in the upper part of the image forming apparatus main body, and four toner bottles 2Y, 2M, 2C, and 2K accommodating replenishing toner are detachably attached to the bottle accommodating portion 2. ing. Toner is replenished from each of the toner bottles 2Y, 2M, 2C and 2K to each developing device 7 via a replenishment path provided between each of the toner bottles 2Y, 2M, 2C and 2K and each of the developing devices 7.

On the other hand, at the lower part of the image forming apparatus main body, a paper feed tray 10 containing the paper P as a recording medium, a paper feed roller 11 for carrying out the paper P from the paper feed tray 10, and the like are provided. In addition to plain paper, the recording medium includes thick paper, postcards, envelopes, thin paper, coated paper (coated paper, art paper, etc.), tracing paper, OHP sheets, and the like. Further, a manual paper feed mechanism may be provided.

A transport path R for passing the paper P from the paper feed tray 10 through the secondary transfer nip and discharging the paper P to the outside of the device is provided in the main body of the image forming apparatus. In the transport path R, a pair of resist rollers 12 as timing rollers for transporting the paper P to the secondary transfer nip by measuring the transport timing are arranged on the upstream side in the paper transport direction from the position of the secondary transfer roller 36. ing.

Further, a fixing device 20 for fixing the unfixed image transferred to the paper P is arranged on the downstream side in the paper transport direction from the position of the secondary transfer roller 36. Further, on the downstream side of the transport path R in the paper transport direction with respect to the fixing device 20, a paper discharge roller pair 13 for discharging the paper P to the outside of the device is provided. Further, a paper ejection tray 14 for stacking the paper P ejected outside the apparatus is provided on the upper surface of the apparatus main body. The paper ejection roller pair 13 constitutes a pair of ejection rollers according to the present invention.

The image forming apparatus 1 may be equipped with a relay unit 1701 and a post-processing apparatus 1900, which will be described later (see FIG. 17).

Subsequently, with reference to FIG. 1, the basic operation of the printer according to the present embodiment will be described.

When the image-drawing operation is started, each photoconductor 5 in each image-forming unit 4Y, 4M, 4C, and 4K is rotationally driven clockwise in the figure, and the surface of each photoconductor 5 is brought to a predetermined polarity by the charging device 6. It is uniformly charged. The surface of each charged photoconductor 5 is irradiated with laser light from the exposure apparatus 9, and an electrostatic latent image is formed on the surface of each photoconductor 5. At this time, the image information to be exposed to each photoconductor 5 is monochromatic image information obtained by decomposing a desired full-color image into yellow, magenta, cyan, and black color information. By supplying toner to the electrostatic latent image formed on each photoconductor 5 in this way by each developing device 7, the electrostatic latent image is visualized (visualized) as a toner image. ..

When the image-drawing operation is started, the secondary transfer backup roller 32 is rotationally driven counterclockwise in the drawing to rotate the intermediate transfer belt 30 in the direction indicated by the arrow in the figure. Further, by applying a constant voltage or a constant current controlled voltage opposite to the charging polarity of the toner to each primary transfer roller 31, the primary transfer nip between each primary transfer roller 31 and each photoconductor 5. A transfer electric field is formed in.

After that, when the toner image of each color on the photoconductor 5 reaches the primary transfer nip as the photoconductor 5 rotates, the toner image on each photoconductor 5 is generated by the transfer electric field formed in the primary transfer nip. Is sequentially superposed on the intermediate transfer belt 30 and transferred. Thus, a full-color toner image is supported on the surface of the intermediate transfer belt 30. Further, the toner on each photoconductor 5 that could not be completely transferred to the intermediate transfer belt 30 is removed by the cleaning device 8. Then, the surface of each photoconductor 5 is statically eliminated by the static elimination device, and the surface potential is initialized.

At the lower part of the main body of the image forming apparatus 1, the paper feed roller 11 starts rotational driving, and the paper P is sent out from the paper feed tray 10 to the transport path R. The paper P sent out to the transport path R is temporarily stopped by the resist roller 12.

After that, the rotational drive of the resist roller 12 is started at a predetermined timing, and the paper P is conveyed to the secondary transfer nip at the timing when the toner image on the intermediate transfer belt 30 reaches the secondary transfer nip. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 30 is applied to the secondary transfer roller 36, whereby a transfer electric field is formed in the secondary transfer nip. .. Then, the toner image on the intermediate transfer belt 30 is collectively transferred onto the paper P by this transfer electric field. Further, the residual toner on the intermediate transfer belt 30 that could not be transferred to the paper P at this time is removed by the belt cleaning device 35 and conveyed to the waste toner container.

After that, the paper P is conveyed to the fixing device 20, and the toner image on the paper P is fixed to the paper P by the fixing device 20. The paper P conveyed from the fixing device is guided in the discharge direction and the re-feeding direction via a branch member 15 for switching between a path for discharging the paper P to the outside of the device and a double-sided reversal path.

In the single-sided paper passing mode, the branch member 15 is opened to stack the paper P discharged to the outside of the device provided on the upper surface of the device main body by the paper ejection roller pair 13 for ejection. Is discharged to the output tray 14.

In the double-sided paper passing mode, the branch member closes in the direction of the arrow, so that the paper P after fixing on the first side is guided to the double-sided reversal path. The paper P guided to the double-sided reversing path is switched back by the pair of reversing rollers 16, transported to the double-sided unit 17, and again transported to the pair of resist rollers 12 and re-fed to the first surface. Similarly, the second side image is printed on the back side of the paper P. Then, the paper P is discharged to the outside of the device by the paper ejection roller pair 13, and is stacked on the paper ejection tray 14.

The above description is an image forming operation when forming a full-color image on paper, but a monochromatic image can be formed by using any one of four image forming units 4Y, 4M, 4C, and 4K. It is also possible to form a two-color or three-color image using two or three image-forming sections.

As shown in FIG. 1, the image reading unit 40 is located above the main body of the image forming apparatus 1. As shown in FIG. 2, the image reading unit 40 abuts and positions the first contact glass 45 located in the transport path of the paper P, the second contact glass 46 on which the paper P can be placed, and one side of the paper P. It has an abutting member 47a capable of the above. Further, the image forming apparatus 1 has an operation unit 150 installed on the upper front side.

The operation unit 150 includes a print key 151, an operation display unit 152, and the like, and when the print key 151 is pressed, the image forming apparatus 1 is requested to start the copying operation. The operation display unit 152 operates and displays various information related to printing and the like.

The curl correction mechanism and the fixing device will be described in detail with reference to FIG. FIG. 3 is a cross-sectional view of the curl correction mechanism and the fixing device.

As shown in FIG. 3, the fixing device 20 is used to melt and permeate the transferred toner image supported on the paper P by heat and pressure to fix it, and as shown in FIG. 3, while being heated. A fixing belt 21 having a rotatable flexibility is provided.

In the fixing device 20, in addition to the fixing belt 21, a pressure roller, which is an opposed rotating body, forms a nip portion N by applying pressure between the fixing belt 21 and the fixing belt 21 in a contact state in contact with the fixing belt 21. 22 is provided. Inside the fixing belt 21, a heater 23 including a plurality of halogen lamps 23a and 23b for heating the fixing belt 21 at a place other than the nip portion N is provided.

Inside the fixing belt 21, a nip forming member 24 which is a base member for forming a nip disposed inside the fixing belt 21, a stay 25 supporting the nip forming member 24, and light radiated from a heater 23. A reflective member 26 is provided to reflect the light on the fixing belt 21. The nip forming member 24, which is a base member for forming a nip, has a sliding sheet (low friction sheet) around which a base pad is wound.

The nip forming member 24 shown in the figure has a flat nip portion N, but is not limited to this shape. For example, when the pressure roller 22 is formed in a concave shape along the peripheral surface, the tip of the paper P passing through the nip portion N is closer to the pressure roller 22 side, so that the separability from the fixing belt 21 is improved. There are advantages. The temperature of the fixing belt 21 is detected by a temperature sensor 27 provided on the side where the paper P enters the nip portion, and is used for feedback processing of the heater 23. In FIG. 3, the arrow F indicates the transport direction of the paper P.

The fixing belt 21 is a thin-walled, flexible sleeve-shaped endless belt, and is composed of a base material and a release layer located on the surface thereof. As the base material, a metal material such as nickel or SUS or a resin material such as polyimide is used. Further, as the release layer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) or polytetrafluoroethylene (PTFE) having releasability to toner is used.

The pressure roller 22 includes a core metal 22a, an elastic layer 22b made of foamable silicone rubber, silicone rubber, fluororubber or the like provided on the surface of the core metal 22a, and PFA or PFA provided on the surface of the elastic layer 22b. It is composed of a release layer 22c made of PTFE or the like. The pressurizing roller 22 is pressurized to the fixing belt 21 side by a pressurizing means (not shown) and is in contact with the fixing belt 21 in contact with the nip forming member 24 as a base member.

At the point where the pressure roller 22 and the fixing belt 21 come into contact with each other, the elastic layer 22b of the pressure roller 22 is crushed, and the nip forming member 24 receives pressure between the pressure roller 22 and the fixing belt 21 to have a predetermined width. Nip portion N is secured.

The pressurizing roller 22 is configured to be rotationally driven by a drive source such as a motor (not shown) provided in the image forming apparatus main body. When the pressure roller 22 is rotationally driven, the driving force is transmitted to the fixing belt 21 by the nip portion N, and the fixing belt 21 is driven to rotate.

In the configuration shown in FIG. 3, the pressure roller 22 is a solid roller, but it may be a hollow roller. In that case, it is also possible to dispose a heating source such as a halogen heater using radiant heat inside the pressurizing roller 22. Further, when the elastic layer 22b is not provided, the heat capacity is reduced and the fixability is improved, but when the unfixed toner is crushed and fixed, minute irregularities on the belt surface are transferred to the image and the solid portion of the image is glossy. Unevenness may occur. In order to prevent this, it is desirable to provide an elastic layer having a thickness of 100 μm or more. Aluminum, iron, stainless steel, or the like can be selected as the pipe-shaped metal used for the hollow roller.

When a heat source is provided in the pressure roller 22, a heat insulating layer is provided on the surface of the support or a heat ray reflecting surface by mirror surface treatment is provided in order to suppress the support from being heated by radiant heat from the heat source. Is desirable. In this case, the heat source is not limited to the halogen heater described above, and an IH heater, a resistance heating element, or a carbon heater can also be used.

On the paper outlet side of the fixing device 20, a separation and transporting mechanism is provided that separates the paper P that has passed through the nip portion in the vicinity of the nip portion and guides the paper P that has passed through the nip portion toward the discharge portion 1300 in the discharge direction. The separation and transfer mechanism includes a belt-side separation and transfer member 201 having a tip close to the fixing belt 21 side on the downstream side in the transfer direction of the paper P passing through the nip portion, and an addition having a tip close to the pressure roller 22 side. It is provided with a compression side separation and conveying member 202.

The belt-side separation and transport member 201 is provided to peel off the tip of the paper P, which is slightly attached to the fixing belt 21, from the fixing belt 21. For this reason, a plate-shaped metal is provided so that the attached paper P can be positioned at a close position where it can be lifted from the surface of the fixing belt 21.

A resin molded product is used for the pressure side separation and transport member 202, and the support rod 202A provided in a part thereof is rotatably supported on the housing side to provide a swing end facing the pressure roller 22. It can swing so that it can be brought into contact with and detached from the pressure roller 22. By swinging with respect to the pressure roller 22, for example, the pressurizing side separation and conveying member 202 swings in a direction away from the pressurizing roller 22 when removing the jammed paper P from the nip portion N, and the nip. A space for inserting a hand into the part N can be created. This makes it possible to access the paper P.

On the downstream side of the separate transport member, a transport auxiliary roller pair 230 composed of a drive roller 204 supported by the pressurizing side separate transport member 202 and a driven roller 203 supported by the holder 207 is arranged.

The drive roller 204 is made of a core metal and a solid rubber material 204b having a high abrasion coefficient and made of silicon, EPDM, urethane, fluororubber, etc. provided on the surface of the core metal so that a paper conveying force can be obtained. The driven roller 203 has a structure in which a hollow pipe-shaped metal surface is covered with a low μ tube (thickness 30 to 300 μm) such as PFA, ETFA, or FEP.

The reason why the driven roller 203 is made of a hollow pipe-shaped metal is that the heat capacity is reduced and the driven roller 203 is immediately warmed by the heat from the fixing in order to prevent dew condensation generated by evaporation from the paper P during fixing and adhering to the driven roller side. To do so.

The reason why the low μ tube is arranged on the surface of the driven roller 203 is that it is difficult for a small amount of toner that has not completely melted after fixing and toner in a semi-melted state to adhere, and even if they adhere, they do not accumulate. Is. Since the driven roller side conveys the image while always in contact with the image surface side, it has the above-described configuration. On the contrary, the drive roller 204 is in contact with the surface opposite to the image surface side. By pressurizing the holder holding the driven roller 203 with a spring, the drive roller 204 and the driven roller 203 come into contact with each other to form a nip, enabling paper transfer.

Next, the configuration of the paper ejection unit in the present embodiment will be described with reference to FIGS. 4 and 5.

4 and 5 show an external perspective view and a cross-sectional view of the paper ejection portion 1300 of the image forming apparatus 1 according to the present embodiment. The paper ejection unit 1300 includes a paper ejection roller pair 13 including a paper ejection roller 1301 and a paper ejection roller 1401, a roller holder 1302, a paper ejection guide plate 1303, and a paper ejection tray 14. The paper ejection roller 1301 and the paper ejection roller 1401 constitute the ejection roller according to the present invention, and the paper ejection roller 1301 constitutes the driven side ejection roller according to the present invention.

The paper P to which the toner has been fixed through the above process is discharged to the paper discharge tray 14 in the cylinder by the paper discharge roller pair 13.

The paper ejection roller 1401 is a roller on the drive side to which power from the motor is transmitted, and is assembled on the main body side of the image forming apparatus 1. The paper ejection roller 1301 is pressurized in the direction of the paper ejection roller 1401 by a spring, and is a driven roller that is brought to the paper ejection roller 1401 by the nip pressure. Further, the paper ejection roller 1301 has a configuration in which it can be attached to and detached from the paper ejection guide plate 1303 via the roller holder 1302.

The paper ejection roller pair 13 will be described with reference to FIGS. 6 to 9. As will be described later, in the present embodiment, the type of the driven side paper ejection roller 1301 applied to the paper ejection unit 1300 is changed according to the path of the paper P after passing through the paper ejection unit 1300.

The paper ejection roller 1301 shown in FIGS. 6 and 7 is a type of paper ejection roller that causes the paper P to form a corrugation. FIG. 6 is a front view of the paper ejection roller 1301, and FIG. 7 is a perspective view thereof.

The paper ejection roller 1301 is composed of rollers 1501, rollers 1502, a through shaft 1503, and a spring receiving roller 1506. The roller 1501 forms a nip with the roller 1504 of the paper ejection roller 1401. Both the rollers 1501 and the rollers 1502 are resins made of POM (polyacetal). Although four rollers 1501 are provided in the present embodiment, the number of rollers 1501 is not limited to this. The roller 1502 is configured to have a diameter larger than that of the roller 1501 in order to sit on the paper P passing through the paper ejection roller pair 13. Two rollers 1502 are provided in the present embodiment, but the number of rollers 1502 is not limited to this.

The through shaft 1503 is a rotation shaft of the paper ejection roller 1301, and the rollers 1501 and the rollers 1502 are assembled around the shaft. By assembling the roller 1502 having a large diameter in the vicinity of the roller 1501, a corrugation is formed on the paper P as shown by the height difference of each roller.

The spring receiving rollers 1506 are attached to the through shaft 1503 in pairs on both sides of some of the rollers 1502. In the present embodiment, the spring receiving rollers 1506 are assembled to the two rollers 1502, but the number of spring receiving rollers to be assembled is not limited to this. The spring receiving roller 1506 comes into contact with the spring 1605 provided on the roller holder 1302 and receives the urging force of the spring 1605.

The paper ejection roller 1401 is composed of a plurality of rollers 1504 and a through shaft 1505. The paper ejection roller 1401 is assembled and fixed to the main body of the image forming apparatus 1. The roller 1504 is provided at a position facing the roller 1501 of the paper ejection roller 1301, and forms a nip with the roller 1501.

Next, a paper ejection roller 1800 of a type that does not form corrugations on the paper P will be described with reference to FIGS. 8 and 9. FIG. 8 is a front view of the paper ejection roller 1800, and FIG. 9 is a perspective view thereof.

The paper ejection roller 1800 is composed of a plurality of rollers 1801 and a through shaft 1802. The roller 1801 forms a nip with the paper ejection roller 1401. Four rollers 1801 are provided in the present embodiment, but the number of rollers 1801 is not limited to this. The paper ejection roller 1800 constitutes the ejection roller according to the present invention.

The plurality of rollers 1801 of the paper ejection roller 1800 are composed of rollers 1504 of the paper ejection roller 1401 and rollers 1801 having the same or smaller rollers forming a nip. For example, the diameters of the rollers 1801 may be substantially equal in size. Therefore, there is no height difference between the rollers 1801, and the paper P that has passed through the paper ejection roller pair including the paper ejection roller 1401 and the paper ejection roller 1800 is not seated.

The through shaft 1802 is the shaft of the paper ejection roller 1800, and the roller 1801 is assembled around the shaft. The paper ejection roller 1401 has the same configuration as that shown in FIGS. 6 and 7.

The configurations of the paper ejection roller 1301 and the roller holder 1302 will be described with reference to FIGS. 10 and 11.

FIG. 10 is a diagram illustrating a case where the paper ejection roller 1301 forming the corrugation is assembled to the roller holder 1302. The paper ejection roller 1301 is assembled to the roller holder 1302 together with a pressure spring (not shown) to form the paper ejection roller group 1603. The paper ejection roller 1301 is held by the roller holder 1302. As shown in FIG. 4, the paper ejection roller group 1603 is detachably attached to the paper ejection guide plate 1303 on the main body side of the image forming apparatus 1.

The roller holder 1302 has a protrusion 1601, a lever 1602, a bearing hook 1604, and a spring 1605 (see FIG. 12). The protrusion 1601 is adapted to engage with the paper ejection guide plate 1303. The lever portion 1602 is inserted into the engaging portion 1303b provided at the other end of the paper ejection guide plate 1303 to fix the paper ejection roller group 1603 to the paper ejection portion 1300.

The bearing hook 1604 is adapted to engage with the through shaft 1503 of the paper ejection roller 1301 when the paper ejection roller 1301 is assembled to the roller holder 1302. When the paper ejection roller 1301 is assembled to the roller holder 1302, the spring 1605 comes into contact with the spring receiving roller 1506 to give a urging force to the paper ejection roller 1301. The roller holder 1302 is a resin made of POM (polyacetal).

As shown in FIG. 11, the protrusion 1601 is inserted into the engaging portion 1303a provided at one end of the paper ejection guide plate 1303, and then the lever portion 1602 is inserted into the engaging portion 1303b provided at the other end of the paper ejection guide plate 1303. Is inserted to fix the paper ejection roller group 1603 to the paper ejection unit 1300.

The procedure for forming the paper ejection roller 1301 will be described below. First, the rollers 1501 and 1502 are press-fitted into the through shaft 1503, the spring receiving roller 1506 is assembled with some play against the through shaft 1503, and the rollers 1501 and 1502 are press-fitted into the through shaft 1503 and then the rollers. The spring receiving rollers 1506 on both sides of 1502 are thrust-fastened in pairs. As a result, the positional relationship between the rollers 1501, the rollers 1502, and the spring receiving rollers 1506 is fixed with respect to the through shaft 1503. The paper ejection roller 1301 is an integrated part, and can be easily attached to and detached from the roller holder 1302. It is also possible to prepare paper ejection rollers having different shapes of the rollers 1501 and the rollers 1502, and to attach / detach them to / from other paper ejection rollers according to the need for corrugation.

A procedure for assembling the paper ejection roller 1301 to the roller holder 1302 will be described with reference to FIGS. 12 and 13. 12 and 13 are views of the paper ejection roller 1301 and the roller holder 1302 as viewed from a side different from that of FIG. From the state shown in FIG. 12, the spring receiving roller 1506 of the paper ejection roller 1301 is brought into contact with the spring 1605 of the roller holder 1302 and pushed in the direction of the arrow in the drawing. The through shaft 1503 is engaged with the bearing hook 1604 by pushing it to a position where the through shaft 1503 engages with the bearing hook 1604. When removing the paper ejection roller 1301, the above procedure may be reversed.

14 and 15 are views for explaining a case where the paper ejection roller 1800 that does not form corrugation is assembled to the roller holder 1302. The assembly method is the same as that shown in FIGS. 12 and 13.

FIG. 16 shows a state in which the relay unit 1701 is mounted in the main body body with the paper ejection roller 1301 capable of forming corrugations assembled. The relay unit 1701 is configured to branch the paper P discharged from the paper discharge roller pair 13 to the in-body discharge unit 1704 and further to the transport path 1705 to the subsequent post-processing device 1900. The relay unit 1701 is removable from the paper ejection unit 1300.

FIG. 17 shows a state in which the relay unit 1701 and the post-processing device 1900 are attached to the image forming apparatus. The relay unit 1701 is adapted to convey the paper discharged from the paper ejection unit 1300 to the subsequent post-processing device 1900. The post-processing device 1900 is adapted to perform various post-processing on the paper conveyed via the relay unit 1701. The various post-processing referred to here is, for example, end binding processing, middle folding processing, and the like.

FIG. 18 is a cross-sectional view for showing a paper transport path of the image forming apparatus 1 to which the relay unit 1701 and the post-processing apparatus 1900 shown in FIG. 17 are attached. The transport path 1703 in the relay unit 1701 indicated by the arrow in FIG. 18 is a path for sending the toner-fixed paper P to the relay unit 1701 via the paper ejection roller pair 13. Since a transport guide plate (not shown) for reversing the paper exists vertically above the relay unit 1701, the upper space of the in-body discharge unit 1704 is widened in order to improve the number of paper stacks and user operability when removing the paper. Is desirable. Therefore, the transport guide plate 1702 of the relay unit 1701 is configured to be inclined downward in the vertical direction, and the transport path 1703 includes a path inclined downward in the vertical direction.

At this time, the tip of the paper P that has passed through the paper ejection roller pair 13 has a large contact angle with the transport guide plate 1702, and when the paper P is corrugated, the paper P is stiff, resulting in poor transport. There is a problem that is likely to occur.

In order to avoid the above problems, in the paper ejection unit 1300 of the image forming apparatus 1 shown in FIG. 18, a paper ejection roller 1800 that does not form corrugation is used. As a result, corrugation is not formed on the paper P, and it is possible to suppress transport defects caused by the stiffness of the paper P.

FIG. 19 is a diagram illustrating a case where a paper discharge tray 14 is provided in the body and a case where the paper P discharged from the paper discharge unit 1300 is different from the case shown in FIG. 18 without using the aftertreatment device 1900 and the relay unit 1701. Is.

As shown in FIG. 19, the transport path 1706 of the paper P draws a smooth curve, and the paper P is discharged from the paper ejection unit 1300 onto the paper ejection tray 14. Unlike the case shown in FIG. 7, since the transport path 1706 of the paper P does not bend sharply, even if the paper P is stiff, a transport defect due to the stiffness does not occur.

Therefore, in the paper ejection unit 1300 of the image forming apparatus 1 shown in FIG. 19, it is possible to remove the curl and curl of the paper by using the paper ejection roller 1301 forming the corrugation, and the transport failure due to the stiffness. Does not occur. In this way, the paper ejection roller can be replaced with an appropriate type according to the path of the paper P ejected from the paper ejection unit 1300. In the present embodiment, two types of paper ejection rollers, a paper ejection roller 1301 and a paper ejection roller 1800, are shown, but the type of the paper ejection roller is not limited to these and may be another type.

As described above, in the image forming apparatus 1 according to the present embodiment, the paper ejection roller 1301 is detachably arranged with respect to the paper ejection unit 1300 via the roller holder 1302, and the paper ejection roller 1301 has a through shaft 1503 and a roller 1501. And the roller 1502 are integrated. Further, the relay unit 1701 can be attached to and detached from the paper ejection unit 1300, and the paper ejection roller 1301, the paper ejection roller 1800 and the roller holder 1302 can be replaced according to the path of the paper P ejected from the paper ejection unit. Has been done.

With this configuration, the seating conditions of the paper ejection roller can be easily changed, and the paper ejection roller 1301 and the paper ejection roller can be adjusted to the waisting conditions according to the presence or absence of the relay unit 1701 and the aftertreatment device 1900. It can be easily done by replacing a part of 1800. Further, by selecting an appropriate waisting condition, it is possible to prevent a defective transfer of the paper P after the paper ejection unit 1300.

Further, since the post-processing device 1900 is attached and detached very infrequently if it is assembled when the main body of the image forming device 1 is installed, the post-processing device 1900 functions sufficiently even in a configuration in which the paper ejection roller 1301 or the paper ejection roller 1800 can be replaced, and automatically. There is no need for a configuration that switches. Therefore, no space is required to move the paper ejection roller forward and backward, which can contribute to space saving and cost reduction.

Further, since the sitting condition can be changed by exchanging the paper ejection roller, the degree of freedom in layout of the transport path of the relay unit 1701 can be improved.

Further, the paper ejection roller 1301 and the paper ejection roller 1800 are integrated with the roller and the through shaft, and the seating condition of the paper P can be changed by exchanging each paper ejection roller, so that the workability of attaching and detaching the paper ejection roller and the roller holder can be changed. Can be improved.

Further, the image forming apparatus 1 may include a paper ejection tray 14 in which the paper P is ejected from the paper ejection unit 1300.

Further, the relay unit 1701 may be attached to the paper ejection unit 1300, and the post-processing device 1900 may be attached to the relay unit 1701. With this configuration, the paper P ejected from the paper ejection unit 1300 can be subjected to various post-processing such as edge binding processing and center folding processing.

Further, the transport path of the paper P in the relay unit 1701 may include a path 1705 that is inclined downward in the vertical direction. With this configuration, the upper space of the in-body discharge unit 1704 can be widened, and the number of paper stacks and the user operability at the time of removing the paper can be improved.

Further, the plurality of rollers included in the paper ejection roller 1301 may be composed of rollers having substantially the same diameter. With this configuration, the paper P passing through the paper ejection unit 1300 is not seated by the paper ejection roller 1301, so that it can be applied when the paper P does not need to be seated.

Further, the plurality of rollers included in the paper ejection roller 1301 may be composed of rollers having different diameters. With this configuration, the paper P passing through the paper ejection unit 1300 is seated by the paper ejection roller 1301, so that it can be applied when the paper P needs to be seated.

In the first embodiment, the configuration of an image forming apparatus that changes the sitting condition according to the path of the paper ejected from the paper ejection unit is shown. However, in general, curling of paper occurs in the fixing device, and it is conceivable to correct the curl immediately after fixing.

More specifically, the fixing device used in the electrophotographic image forming apparatus forms a toner image on paper by heating and pressurizing the nip portion. At this time, due to the temperature difference between the heating side and the pressurizing side, the evaporation of water due to heating is biased, so that the paper is curled. The curled paper causes poor transport due to being caught in the transport path, the transfer portion with the finisher, etc., and also causes poor alignment of the paper on the output tray.

As a technique corresponding to this, a decaler means for correcting curl of paper is already known. However, in the conventional decal means, the curl is always forcibly applied in the opposite direction by the guide member. Therefore, for example, in the case of thick paper passing paper, there are the following three problems.

(1) Since the back curl that the sheet curls on the back surface does not occur in the fixing device, if the guide plate is always in the position where the curl is applied in the opposite direction, the guide plate is conversely curled and the face curl is conversely. (2) Since the contact force between the guide plate and the paper is strong, the guide member causes damage (scratches) / wear of the guide member on the back surface of the paper. (3) Since the paper has high rigidity, the tip may bend when the tip comes out of the roller pair and comes into contact with the guide member, making it difficult to stabilize the transport.

For example, in Patent Document 3, for the purpose of correcting the side curl generated by the temperature difference between the center and the end of the fixing nip, the convex portion is stored when the temperature difference between the center and the end of the fixing nip disappears over time. The configuration is disclosed in which the correction of the side curl is released.

With the configuration described in Patent Document 3, curl correction and curl correction can be canceled. However, what can be corrected is limited to side curls, and as described above, curls are added on the contrary, damage (scratches) on the back surface of the paper when using thick paper / wear of the guide member, and when the tip comes into contact with the guide member. The problem that it is difficult to stabilize the transport due to bending of the tip has not been solved.

The image forming apparatus according to the second embodiment described below is made to solve the above-mentioned problem, and the decal means is appropriately turned on and off depending on the paper type and the presence or absence of the waist in the paper ejection portion. The purpose is to prevent transport problems due to decals by setting to.

(Second Embodiment)
Hereinafter, the image forming apparatus according to the second embodiment will be described.

In the image forming apparatus according to the second embodiment, the same components as those in the first embodiment are used with the same reference numerals as those in the first embodiment shown in FIGS. 1 to 19. It will be explained and only the differences will be described in detail.

The overall configuration of the image forming apparatus in the second embodiment is the same as that in the image forming apparatus 1 in the first embodiment shown in FIG. 1, and the description thereof will be omitted.

The position of the guide member 205 will be described with reference to FIGS. 20 and 21. Immediately downstream of the transfer auxiliary roller pair 230, a movable guide member 205 for guiding the paper P discharged from the transfer auxiliary roller pair 230 is provided, and the first position shown in FIG. 20 and FIG. 21 It is configured to be movable in two stages of the second position (described later) shown in.

When the guide member 205 is arranged at the position shown in FIG. 20, the direction of the paper P discharged from the transport auxiliary roller pair 230 (the direction perpendicular to the line connecting the centers of the pair of the transport auxiliary roller pair 230). ) On the other hand, by arranging the paper at a position that blocks the path, the paper tip comes into contact with the guide member 205 at an angle θ, and then the paper P is pressed against the guide member 205 by the transport force of the transport auxiliary roller pair 230. However, it will be transported.

Finally, the transport roller nip can be bent to the opposite side of the back curl by transporting the roller nip at an angle θ1. By adopting such a transport path, the paper P ejected from the guide member 205 improves the back curl generated in the fixing nip portion N and can be discharged to the outside of the image forming apparatus 1.

However, since the back surface of the paper and the guide member 205 are positively brought into contact with each other, the transport resistance with the guide member 205 is large and stress is applied to the paper itself. There is a possibility that contact marks may be generated with the guide member 205, or conversely, the guide member 205 itself may be worn.

Further, when the second side of the paper is passed in the double-sided paper passing mode, the side with the image (first side) comes into contact with the guide member 205, and image scratches and glossy streaks are likely to occur. The reason is that immediately after the fixing unit, the second image surface is being fixed, and the first side image on the back side is also heated again because the paper passes through the nip portion N, but the outermost surface portion of the toner is in a warm state. This is because if it is rubbed strongly, it is likely to be peeled off or the gloss is changed.

On the other hand, when the guide member 205 is arranged at the position shown in FIG. 21, the direction of the paper discharged from the transport auxiliary roller pair 230 (with respect to the line connecting the centers of the rollers of the transport auxiliary roller pair 230). The guide member 205 is arranged at a retracted position with respect to the paper P (in the perpendicular direction) so as not to positively contact the paper P. In this case, the back curl during paper transport cannot be corrected, but since stress is not applied to the paper, the above-mentioned back surface scratches, abrasion, image scratches, and gloss streaks do not occur on the paper.

Since it is not possible to achieve both curl correction and image scratch prevention at the position of one guide member 205, in the present embodiment, the guide member 205 is driven by the driving means (described later) in each of the paper passing modes described later. The positions of the guide member 205 are switched to the positions shown in FIGS. 20 and 21, so that both can be achieved. Specifically, by movably arranging the guide member 205 / branch member 15 as follows, each paper passing mode is supported.

First, when the paper thickness is equal to or less than a predetermined value in the single-sided paper passing mode in which the image is transferred to only one side of the paper P, the guide member 205 and the branch member 15 are moved to the positions shown in FIG. 22 (A). At this time, the position of the guide member 205 is the first position. This is because when the paper thickness is not large, it is not necessary to consider the friction with the guide member 205 so much, and it is not necessary to convey the paper P to the reversing path.

When the paper thickness is larger than a predetermined value in the single-sided paper passing mode, the guide member 205 and the branch member 15 are moved to the positions shown in FIG. 22 (B). At this time, the position of the guide member 205 is the second position. This is because when the paper thickness is large, it is necessary to consider the friction with the guide member 205 so much. In this embodiment, 160 g / m2 is adopted as a predetermined value of the paper thickness, but it is not always limited to this value. For example, when it is desired to widen the range of the paper thickness to be curled, a larger value is used. May be a predetermined value.

Next, in the double-sided paper passing mode, the guide member 205 is arranged at an open position on both the first and second sides of the paper P, and is inverted / re-inverted with the discharge path for discharging the paper P to the outside of the image forming apparatus 1. By moving and arranging the branch member 15 for switching the paper feed path, the paper P is guided to the reverse / refeed path after the first surface is fixed, and to the discharge path after the second surface is fixed.

Specifically, when passing the first side of the paper P in the double-sided paper passing mode, the guide member 205 and the branch member 15 are moved to the positions shown in FIG. 22C, and the paper P and the guide member 205 are moved to each other. Guide the paper P to the reverse / refeed path without contact. At this time, the position of the guide member 205 is the second position.

When passing the second side of the paper P in the double-sided paper passing mode, the guide member 205 and the branch member 15 are moved to the positions shown in FIG. 22 (D), and the paper P and the guide member 205 are not brought into contact with each other. Guide P to the discharge route. At this time, the position of the guide member 205 is the second position.

In addition to the above-mentioned single-sided printing / double-sided printing and paper thickness, the positions of the guide member 205 and the branch member 15 may be moved depending on the paper type. For example, in recycled paper that is easily curled, the guide member 205 is set to the first position, and in glossy paper, the guide member 205 is set to the second position.

Further, the positions of the guide member 205 and the branch member 15 may be moved according to the type of the paper ejection roller. For example, when the paper ejection roller 1301 capable of forming corrugation is used, the guide member 205 is set to the second position without decaling by the guide member 205, and when the paper ejection roller 1800 not forming corrugation is used, the guide member 205 is used. The guide member 205 is set to the first position in order to perform the decal by.

Various information used for determining the paper passing mode, single-sided printing / double-sided printing, paper thickness, paper type, etc. are set using the information set in the operation display unit 152 provided on the main body shown in FIG. The operation display unit 152 constitutes the setting means in the present invention.

The configuration of the guide member 205 and the driving means of the guide member 205 will be described with reference to FIGS. 23 to 29.

FIG. 23 is a view of the pressurizing side separated transport member 202 from the direction of the paper transport surface. The drive roller 204 of the transfer auxiliary roller pair 230 is rotatably supported at both ends of the pressurizing side separation transfer member 202 via a slide bearing 208. The drive roller 204 is configured to be rotatable by transmitting a driving force from a drive input source to a drive gear 210 provided on the drive roller 204 axis via an idler gear 211 and driving the drive roller 204.

The guide member 205 is arranged downstream of the drive roller 204 and is coaxially supported with the drive roller 204 by being fixed to the pressurizing side separation and transport member 202 via the sliding bearings 208 at both ends of the drive roller 204. It has a structure that can rotate around the axis. The drive roller 204 contacts and rotates with the inner diameter portion of the sliding bearing 208, and the guide member 205 contacts and rotates with the outer diameter portion of the sliding bearing 208.

With the above configuration, the distance gap between the drive roller 204 and the guide member 205 can be configured to have the least dimensional tolerance stacking of parts (only the radial distance tolerance from the axial center of each part), and the drive roller 204. The guide member 205 can be moved while the distance between the guide member 205 and the guide member 205 is maintained with high accuracy.

As shown in FIG. 22, since the guide member 205 and the branch member 15 located downstream are allowed to move independently depending on the paper passing mode, the guide member 205 and the branch member 205 are viewed from the viewpoint direction of FIG. 22. It is necessary to prevent each of them from interfering with each other even if they overlap with 15.

Therefore, the guide member 205 is formed in a plurality of claw-shaped ribs over the longitudinal direction. As shown in FIG. 29, by configuring the rib member on the claw of the branch member 15 to be inserted between the claw-shaped ribs of the guide member 205, they can be moved independently by overlapping.

Further, as shown in FIG. 24, the drive roller 204 is a dumpling-shaped roller in which a plurality of rubber rollers are arranged, and is configured so that the rib shape of the guide member 205 is inserted into a portion without the rubber rollers. .. Therefore, when viewed from the Y direction of the cross section shown in FIG. 24, the outer diameter of the rubber roller and the rib of the guide member 205 overlap.

The tip of the guide member 205 is arranged close to the nip portion of the transport auxiliary roller pair 230 (circled in FIG. 24). This configuration is because it is important to arrange the tip of the guide member close to the drive roller 204 in order to reliably spread and guide the paper P discharged from the transport auxiliary roller pair 230. Further, it is important to arrange the tip close to the nip portion from the viewpoint of the curl correction effect of bending the paper P coming out of the transport auxiliary roller pair 230 and the stabilization of transportability.

FIG. 26 shows a comparative diagram when the tip of the guide member is arranged so as to overlap the drive roller and when the tip of the guide member is arranged so as to be separated from the outer diameter of the rubber of the drive roller by a certain gap. The solid line L in the figure shows the case where the tip of the guide member 205 is arranged so as to overlap the drive roller 204, and the broken line L'is arranged so that the tip of the guide member 205 is separated from the rubber outer diameter of the drive roller 204. It shows the case where it is made to do.

When the tip of the guide member 205 is arranged away from the outer diameter of the rubber of the drive roller 204, it is arranged as shown by the broken line L'in order to make the curl correction effect of the guide member 205 the same. In this case, the paper discharged from the transport auxiliary roller pair 230 is discharged in the direction perpendicular to the line connecting the centers of the rollers of the transport auxiliary roller pair 230, so that the contact angle between the paper tip and the guide member 205 is θ ′. Is smaller than the contact angle θ when they are arranged in an overlapping manner.

When this contact angle becomes small, the tip of the paper bends and bends and is transported, and in the worst case, the risk of jamming increases. On the contrary, when the contact angle between the tip of the paper and the guide member 205 is large (shallow), the curl correction effect of bending the paper P by the guide member 205 is reduced.

From the above viewpoint, it is necessary to bring the tip of the guide member 205 closer to the nip of the transfer assist roller pair 230. Therefore, the transfer assist drive roller 204 is used as a dumpling-shaped roller, and the rib of the guide member 205 enters the portion without the rubber roller. It is configured as follows.

As shown in FIG. 24 (A), the guide member 205 is urged by the tension spring 209 in the direction of closing the transport path, and the stopper portion 205A of the guide member 205 comes into contact with a part of the pressure side separation transport member 202. It is configured to stop at the position. The position of the guide member 205 at this time is the first position for changing the angle in the transport direction of the paper P discharged from the transport auxiliary roller pair 230 shown in FIG. 24 (B).

As shown in FIG. 25 (A), the main body side of the image forming apparatus 1 is a solenoid 220 and a link member which are driving means for moving the guide member 205 to a second position where the angle of the paper P in the transport direction is not changed. It has 221 and. The link member 221 constitutes the link mechanism according to the present invention.

As shown in FIGS. 27 and 28, the link member 221 is connected to the guide member 205 and is rotatably configured around the fulcrum 221A, and the tip of the link member 221 is lifted in conjunction with the suction of the solenoid 220. As a result, it comes into contact with the guide member 205. When the solenoid 220 is turned on, a suction force is generated, and when the solenoid 220 is turned off, a suction force is not generated.

By making the suction force of the solenoid 220 larger than the urging force of the tension spring 209 to the guide member 205, the guide member 205 rotates counterclockwise and moves to the second position. The position of the guide member 205 when the solenoid 220 is sucked and stopped is the second position shown in FIG. 25 (B). The guide surface of the guide member 205 at the second position is substantially vertical with respect to the horizontal direction so as not to change the transport direction of the paper P.

In the present embodiment, the first position where the positional relationship between the guide member 205 and the transport auxiliary roller pair 230 is severe is configured so that the position is completed in the unit, and the second position is the image forming apparatus 1. Although it is configured to be determined by the solenoid 220 which is the driving means on the main body side and the link member 221, it may be reversed.

Further, the position of the guide member may be determined in multiple stages by using a stepping motor or the like as the driving means of the guide member 205. For example, when it is desired to remove weak curls, the position of the guide member may be set to an intermediate position between the first position and the second position.

As described above, the image forming apparatus 1 according to the present embodiment has an operation display unit 152 for setting the type of the paper P to be fed to the fixing device 20, and images the paper P on the downstream side of the fixing device 20. The paper P discharged from the transport auxiliary roller pair 230 and immediately after the transport auxiliary roller pair 230 and the transport auxiliary roller pair 230 is guided to the upstream side of the branch member 15 that switches between the discharge path to the outside of the forming device 1 and the double-sided reversal path. The guide member 205 is provided.

Further, the first position where the guide member 205 comes into contact with the paper P and changes the angle formed by the path of the paper P discharged from the transport auxiliary roller pair 230 and the second position which does not change the angle formed by the path of the paper P. It has a solenoid 220 and a link member 221 that can be moved to a position, and the solenoid 220 and the link member 221 move the guide member 205 to the first position and the second according to the type of paper P set in the operation display unit 152. It is configured to move to any of the positions of.

With this configuration, the decal can be turned on and off appropriately by moving the position of the guide member 205 to the first position or the second position by the solenoid 220 and the link member 221 according to the type of the paper P. .. In addition, by properly setting the decal on / off, it is possible to prevent a transport failure due to the decal.

Further, the solenoid 220 and the link member 221 may be configured to move the guide member 205 to either the first position or the second position depending on the type of the paper ejection roller. With this configuration, the guide member is moved to the second position when the paper ejection roller 1301 for waisting is used, and the guide member is moved to the first position when the paper ejection roller 1800 for non-waisting is used. By doing so, the degree of decal with respect to the paper P can be made appropriate.

Further, the solenoid 220 and the link member 221 may be configured so that the guide member 205 can be moved to an arbitrary position between the first position and the second position. With this configuration, the decal by the guide member 205 can be set to an arbitrary degree.

Further, the guide member 205 may be rotatably supported at a position coaxial with the axis of the drive roller 204 of the transport auxiliary roller pair 230, and may be movable to the first position and the second position by rotationally moving. With this configuration, the distance gap between the drive roller 204 and the guide member 205 can be configured to have the least dimensional tolerance stacking of parts, and the distance between the drive roller 204 and the guide member 205 can be maintained with high accuracy. The guide member 205 can be moved in the leaning state.

Further, the solenoid 220 and the link member 221 may change the position of the guide member 205 depending on the thickness of the paper P. With this configuration, in order to prevent the generation of contact marks due to contact with the guide member 205 on thick paper with strong stiffness, the guide member 205 can be set to the second position and the paper P and the guide member 205 can be prevented from coming into contact with each other. Further, for the paper P whose paper thickness is equal to or less than a predetermined value, the guide member 205 can be set as the first position and the paper P can be stiffened.

Further, the solenoid 220 and the link member 221 may be configured so that the guide member 205 can be moved by operating the link member 221 by turning the solenoid 220 into an on state or an off state.

Further, the transport auxiliary roller pair 230 is composed of a drive roller 204 made of a rubber roller and a driven roller 203 having a high peelability on the surface, so that the non-image surface side of the paper P becomes the drive roller 204 during single-sided paper passing. It may be configured. With this configuration, it is possible to prevent toner from adhering to and accumulating on the surface of the driven roller 203 that comes into contact with the image surface side.

In the second embodiment, the configuration of the image forming apparatus that turns on and off the decal means according to the paper thickness is shown. On the other hand, factors that affect the occurrence of curl include not only the paper thickness but also the water content in the paper at the time of fixing. For example, it is known that the higher the water content in the paper, the more likely it is that curl after fixing occurs, and the lower the water content, the less likely it is that curl after fixing occurs.

The image forming apparatus according to the third embodiment described below aims to prevent a transfer failure due to decals by appropriately setting on / off of the decal means according to the humidity.

(Third Embodiment)
Hereinafter, the image forming apparatus according to the third embodiment will be described.

In the image forming apparatus according to the third embodiment, the same components as those in the first and second embodiments are the same as those of the first and second embodiments shown in FIGS. 1 to 29. The same reference numerals will be used for explanation, and only the differences will be described in detail.

The image forming device 1 includes an image forming unit A, a fixing device 20, an operation display unit 152, a guide member 205, a solenoid 220, a temperature / humidity sensor 1600, a temperature / humidity sensor 1700, and a control unit 100 (see FIG. 32). ) And are included.

As shown in FIG. 30, the temperature / humidity sensor 1600 is provided in the vicinity of the operation unit 150 (see FIG. 2) at the upper part of the image forming apparatus 1. The temperature / humidity sensor 1600 is adapted to detect the temperature and humidity of the outside air of the image forming apparatus 1. The temperature / humidity sensor 1600 constitutes the humidity detecting means according to the present invention.

In the example shown in FIG. 30, the temperature / humidity sensor is provided in the upper part of the image forming apparatus 1, but as shown in FIG. 31, the temperature / humidity sensor 1700 is provided inside the paper feed tray 10 provided in the lower part of the image forming apparatus 1. May be good. The temperature / humidity sensor 1700 is adapted to detect the temperature and humidity in the image forming apparatus 1 or the paper feed tray 10.

The means for detecting the outside air of the image forming apparatus 1 and the temperature and humidity in the apparatus (or in the paper feed tray 10) are not necessarily limited to these.

Next, the configuration of the control unit 100 will be described with reference to FIG. 32.

As shown in FIG. 32, a temperature / humidity sensor 1600, a temperature / humidity sensor 1700, an operation display unit 152, and a solenoid 220 are connected to the control unit 100, respectively.

The control unit 100 includes, for example, a microcomputer including a CPU, a RAM, a ROM, an input / output interface, and the like, and moves the guide member 205 according to the type of paper P and the outside air or the humidity in the image forming apparatus 1. Is designed to control.

The temperature / humidity sensor 1600 detects the humidity of the outside air, and the temperature / humidity sensor 1700 detects the humidity inside the image forming apparatus 1. The operation display unit 152 can set various information such as the type of paper P, the paper thickness, single-sided printing / double-sided printing, and displays these information. The solenoid 220 is adapted to move the guide member 205 to either the first position or the second position in conjunction with the link member 221.

FIG. 33 is a diagram comparing the on / off relationship of the decal depending on the paper thickness and the humidity in the image forming apparatus 1 of the present embodiment with another image forming apparatus of the present state. In FIG. 33, ON moves the guide member 205 to the first position shown in FIG. 22 (a) to turn on the decal, and OFF moves the guide member 205 to the second position shown in FIG. 22 (b). It shows the state of moving and turning off the decal.

Other current image forming devices control the on / off of the decal according to the paper type and the paper thickness of the paper P. When the paper P is thin paper or plain paper, the decal is turned on and the guide member 205 is moved to the first position. When the paper P is thick paper, the decaler is turned off and the guide member 205 is moved to the second position. Here, thin paper has a paper thickness of 59 g / m2 or less, plain paper has a paper thickness of more than 59 g / m2 and 160 g / m2 or less, and thick paper has a paper thickness of more than 160 g / m2. ..

On the other hand, the image forming apparatus 1 of the present embodiment controls the on / off of the decal by not only the paper type and the paper thickness of the paper P but also the humidity. The humidity here is the temperature of the outside air of the image forming apparatus 1 detected by the temperature / humidity sensor 1600, or the humidity in the image forming apparatus 1 or the paper feed tray 10 detected by the temperature / humidity sensor 1700.

When the paper type of the paper P is thin paper, the decal is turned on and the guide member 205 is moved to the first position regardless of the humidity. When the paper type of the paper P is plain paper and the humidity is low, curling is unlikely to occur. Therefore, the decal is turned off and the guide member 205 is moved to the second position. If the paper type of the paper P is plain paper and the humidity is high, curling is likely to occur. Therefore, the decal is turned on and the guide member 205 is moved to the first position. When the paper type of the paper P is thick paper, the decaler is turned off and the guide member 205 is moved to the second position regardless of the humidity.

The case where the humidity is high means the case where the humidity exceeds 50%, and the case where the humidity is low means the case where the humidity is 50% or less.

By controlling the on / off of the decal in consideration of not only the paper thickness but also the humidity, decals are applied when the paper does not curl at low humidity or when the amount of curl is small, and reverse curl is given to the paper. It is possible to prevent it from happening.

FIG. 34 is a flow chart of on / off control of the decal in the present embodiment.

The control unit 100 determines whether or not the paper P is thin paper (step S1). When the paper P is thin paper, the control unit 100 turns on the decal (step S2), and moves the guide member 205 to the first position by the solenoid 220 and the link member 221 which are the driving means. Next, the control unit 100 ends the determination of turning on / off the decal (step S6).

When the paper P is not thin paper, the control unit 100 determines whether or not the paper P is plain paper (step S3). When the paper P is plain paper, the control unit 100 determines whether the outside air or the humidity in the image forming apparatus 1 is high humidity (step S4). When the humidity in the outside air or the image forming apparatus 1 is high, the control unit 100 turns on the decal (step S2), and the solenoid 220 and the link member 221 as the driving means place the guide member 205 in the first position. Move. Next, the control unit 100 ends the determination of turning on / off the decal (step S6).

When the paper P is not plain paper (= thick paper), the control unit 100 turns off the decal (step S5), and the solenoid 220 and the link member 221 which are the driving means move the guide member 205 to the second position. Move it. Further, even when the control unit 100 determines in step S4 that the humidity in the outside air or the image forming apparatus 1 is low, the decaler is turned off (step S5), and the solenoid 220 and the link member 221 which are the driving means are used for the first step. The guide member 205 is moved to the position of 2. Next, the control unit 100 ends the determination of turning on / off the decal (step S6).

As described above, the image forming apparatus 1 according to the present embodiment has an operation display unit 152 for setting the type of the paper P to be fed to the fixing device 20, and images the paper P on the downstream side of the fixing device 20. The paper P discharged from the transport auxiliary roller pair 230 and immediately after the transport auxiliary roller pair 230 and the transport auxiliary roller pair 230 is guided to the upstream side of the branch member 15 that switches between the discharge path to the outside of the forming device 1 and the double-sided reversal path. The guide member 205 is provided.

Further, the first position where the guide member 205 comes into contact with the paper P and changes the angle formed by the path of the paper P discharged from the transport auxiliary roller pair 230 and the second position where the angle formed by the path of the paper P does not change. The solenoid 220 and the link member 221 have a solenoid 220 and a link member 221 that can be moved to, and the solenoid 220 and the link member 221 move the guide member 205 to the first position and the second position according to the type of paper P set in the operation display unit 152. It is configured to move to one of the positions.

Further, a temperature / humidity sensor 1600 for detecting the humidity of the outside air is further provided, and the solenoid 220 and the link member 221 move the guide member 205 in the first position and the second position according to the humidity detected by the temperature / humidity sensor 1600. It is configured to move to either.

With this configuration, the position of the guide member 205 is moved to the first position or the second position by the solenoid 220 and the link member 221 according to not only the type of the paper P but also the humidity of the outside air, so that the decal is turned on and off. Can be set appropriately. In addition, it is possible to prevent a transport failure due to decaling on the paper P in which curling does not occur or the amount of curling is small.

Further, a temperature / humidity sensor 1700 for detecting the humidity in the image forming apparatus may be provided.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

According to the present invention, the paper ejection failure is prevented by changing the seating conditions according to the paper conveying path after the paper ejection portion, and the space saving of the apparatus is realized, and the paper ejection roller of the paper ejection portion and the paper ejection portion. The workability of attaching and detaching the roller holder can be improved, which is useful for the image forming apparatus in general.

1 Image forming device 13 Paper ejection roller pair (1 pair of ejection rollers)
14 Paper output tray 15 Branch member 20 Fixing device 152 Operation display unit (setting means)
205 Guide member 220 Solenoid (driving means)
221 Link member (driving means)
230 Conveyance auxiliary roller vs. 1300 Paper ejection part 1301 Paper ejection roller (roller for ejection on the driven side)
1302 Roller holder 1401 Paper ejection roller (discharge roller)
1501 Roller 1502 Roller 1503 Through shaft 1600 Temperature / humidity sensor (humidity detection means)
1700 Temperature / humidity sensor (humidity detection means)
1701 Relay unit 1800 Paper ejection roller (discharge roller)
1801 Roller 1802 Through shaft 1900 Post-processing device A Image forming unit P Paper

Japanese Patent No. 4872471 Japanese Unexamined Patent Publication No. 2001-48392 Japanese Unexamined Patent Publication No. 6-202506

Claims (8)

Image formation having a fixing device for fixing the image to the paper after transferring the image formed by the image forming unit onto the paper, and a setting means for setting the type of the paper to be fed to the fixing device. In the device
On the downstream side of the fixing device and on the upstream side of the branch member that switches between the path for discharging the paper to the outside of the image forming apparatus and the double-sided reversal path, the transfer auxiliary roller pair and the transfer auxiliary roller immediately after the transfer auxiliary roller pair. A guide member for guiding the paper discharged from the pair is provided.
A first position where the guide member comes into contact with the paper and changes the angle formed by the paper discharged from the transport auxiliary roller pair and the guide member, and the paper discharged from the transport auxiliary roller pair. It has a driving means that can move to a second position that does not change the angle formed by the guide member.
At the time of double-sided printing on the paper, the guide member is arranged at the second position regardless of the type of the paper.
The guide member is rotatably supported at a position coaxial with the roller shaft on the drive side of the transport auxiliary roller pair, and is configured to be movable to the first position and the second position by rotating and moving. An image forming apparatus as a feature. The image forming apparatus according to claim 1, wherein the driving means can move the guide member to an arbitrary position between the first position and the second position. It said drive means, an image forming apparatus according to any one of claims 1 or claim 2, characterized in that changing the position of the guide member by a paper thickness of the paper. The driving means includes a solenoid provided in the main body of the image forming apparatus and a link mechanism interlocking with the solenoid and connected to the guide member, and by turning the solenoid on or off, the driving means is described. The image forming apparatus according to any one of claims 1 to 3 , wherein the guide member can be moved by operating the link mechanism. The claim is characterized in that the transport auxiliary roller pair is composed of a drive roller made of a rubber roller and a driven roller having a surface imparted to be peelable, and the non-image surface side of the paper is used as a drive roller during single-sided paper passing. The image forming apparatus according to any one of claims 1 to 4. Further equipped with a humidity detection means to detect the humidity of the outside air,
Said drive means in response to the humidity detected by said humidity detecting means, said claims 1 to guide member and moving to either of the first position and the second position 5 The image forming apparatus according to any one of the above. Further equipped with a humidity detecting means for detecting the humidity in the image forming apparatus,
Said drive means in response to the humidity detected by said humidity detecting means, said claims 1 to guide member and moving to either of the first position and the second position 5 The image forming apparatus according to any one of the above. Further provided with a humidity detecting means for detecting the humidity in the paper feed tray accommodating the paper as the humidity in the image forming apparatus.
The image according to claim 7 , wherein the driving means moves the guide member to either the first position or the second position according to the humidity detected by the humidity detecting means. Forming device.

Images