JP2014182153A - Transfer entrance conveyance mechanism and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer entrance conveyance mechanism which is capable of suppressing the occurrence of failures caused by an attitude change by stabilizing the attitude of the top end of a recording material entering a transfer region, regardless of the thickness and weight of the recording material and the state of curling or the like of the recording material.SOLUTION: A transfer entrance conveyance mechanism 60 guiding a paper P includes a transfer entrance guide plate 71 guiding the recording material to the entrance of the transfer region, while regulating the attitude from below and a movable mechanism 70 changing the inclination angle of the transfer entrance guide plate 71. The transfer entrance conveyance mechanism 60 includes at least one of basis weight detection means for detecting the basis weight of the paper P and curling amount detection means for detecting the curling amount of the top end of the paper P. The inclination angle of the transfer entrance guide plate 71 is changed by the movable mechanism 70, based on the detection result of the provided detection means.

Description

  The present invention relates to a transfer inlet transport mechanism that guides a recording material such as transfer paper at the entrance of a transfer area where an image carrier that carries a toner image and a transfer unit face each other, and image formation including the transfer entrance transport mechanism It relates to the device.

Conventionally, a toner image formed on an image carrier such as a photoconductor is recorded in a transfer region where the image carrier and the transfer unit face each other directly or via an intermediate image carrier such as an intermediate transfer belt. 2. Description of the Related Art An image forming apparatus is known that is transferred onto a material and then fixed on a recording material with a fixing device.
Also known is a configuration in which a transfer nip portion is formed by an image carrier and transfer means in a transfer region.

In the image forming apparatus adopting the transfer method as described above, when the thickness and weight of the recording material entering the transfer area and the state of the recording material such as curl change, the leading edge of the recording material when entering the transfer area Various inconveniences occur due to the different postures of the parts.
For example, if the paper type of the recording material entering the transfer area changes, the basis weight decreases, the thickness of the recording material decreases, or the weight decreases, the stiffness of the recording material becomes weaker and the There is a case where the posture of the leading end portion of the recording material that enters changes so as to hang downward. Similarly, when the temperature of the image forming apparatus or the temperature and humidity environment in which the recording material is stored changes and the weight of the recording material changes, the posture of the leading edge of the recording material that enters the transfer area is also the same. May change to hang down.
In addition, in a recording material in which both ends in the recording material conveyance direction are curled upward, the posture of the recording material entering the transfer area changes so as to bend upward, and in a recording material in which both ends are curled downward. Then, the posture of the leading end of the recording material entering the transfer area changes so as to hang downward.

When the posture of the leading end of the recording material entering the transfer area is different as described above, for example, if a foam roller is used as a transfer roller of a transfer unit that forms an image carrier and a transfer nip, Such a problem may occur.
A phenomenon that the toner remaining on the surface of the foam roller or the toner extruded from the foam layer near the surface of the foam roller due to the collision of the recording material adheres to the edge surface of the recording material and becomes dirty, so-called edge surface contamination occurs. Resulting in.
Even if a foaming roller is not used as the transfer roller, the recording material may be directly collided with the image carrier or the transfer roller and the leading end of the recording material may be broken. In some cases, the recording material may be jammed in the transfer area.

  The present invention has been made in view of the above problems, and its purpose is to stabilize the posture of the leading end of the recording material entering the transfer area regardless of the thickness, weight, curl, etc. of the recording material. And providing a transfer entrance transport mechanism capable of suppressing the occurrence of defects due to posture changes.

  In order to achieve the above object, according to the first aspect of the present invention, an image carrier that carries a toner image and a transfer unit that transfers the toner image carried on the image carrier onto a recording material face each other. In the transfer inlet transport mechanism for guiding the recording material to the entrance of the transfer region, the transfer entrance guide plate for guiding the recording material while regulating the posture from below to the entrance of the transfer region, and the inclination of the transfer entrance guide plate An inclination angle changing means for changing the angle, and having at least one of a basis weight detecting means for detecting the basis weight of the recording material and a curl amount detecting means for detecting the curl amount of the tip portion of the recording material, The inclination angle of the transfer inlet guide plate is changed by the inclination angle changing means based on the detection result of the one detection means.

The present invention provides a transfer entrance guide plate in which the inclination angle is changed by the inclination angle changing means based on the detection result of the basis weight detecting means or the curl amount detecting means even if the thickness of the recording material or the state of curling changes. The recording material can be guided to the entrance of the transfer area while regulating the posture.
Therefore, the posture of the leading end portion of the recording material entering the transfer area can be stabilized regardless of the thickness of the recording material, the curl, and the like.

  The present invention stabilizes the posture of the leading end of the recording material entering the transfer region regardless of the thickness, weight, curl, etc. of the recording material, and suppresses the occurrence of defects due to the posture change. A transport mechanism can be provided.

1 is a schematic explanatory diagram of a printer according to an embodiment. Explanatory drawing of a secondary transfer apparatus. Explanatory drawing of a transfer entrance conveyance mechanism. Explanatory drawing of the cam part of a transfer entrance conveyance mechanism. Explanatory drawing of a paper weight detection sensor and a paper detection sensor.

  Hereinafter, an embodiment in which the present invention is applied to a cooling / conveying device provided in an image forming apparatus will be described with reference to the accompanying drawings. First, an outline of a printer 300 that is an image forming apparatus according to the present embodiment common to the respective examples will be described. FIG. 1 is a schematic configuration diagram of a printer 300 that is an image forming apparatus according to the present embodiment, FIG. 2 is an explanatory diagram of a secondary transfer device, FIG. 3 is an explanatory diagram of a transfer inlet transport mechanism, and FIG. FIG. 5 is an explanatory diagram of a cam portion of the entrance conveyance mechanism, and FIG. 5 is an explanatory diagram of a paper weight detection sensor and a paper detection sensor.

Here, in this embodiment, the present invention is a monochrome printer 300 provided with a drum-shaped photoconductor 1 using black toner as an image carrier on an intermediate transfer belt 12 as an intermediate image carrier. An example applied to is described. However, the present invention is not limited to such a configuration. For example, a so-called tandem configuration in which four photoconductors are provided side by side on the extended surface of the intermediate transfer belt, or a configuration in which a plurality of developing devices are provided for each toner color for image formation around one photoconductor. The present invention can also be applied to other image forming apparatuses.
First, the basic configuration and operation of the printer 300 of this embodiment will be described with reference to FIG.

As shown in FIG. 1, the printer 300 of this embodiment forms a toner image on the photosensitive member 1, primarily transfers the toner image onto the intermediate transfer belt 12, and the primary transferred toner image is transferred to the toner image. Then, secondary transfer is performed on a sheet P which is a recording material such as a transfer sheet. This is an electrophotographic image forming apparatus of a so-called intermediate transfer type that obtains an output image by fixing the toner image transferred onto the paper P.
This printer 300 is provided with a transfer unit 10 having an intermediate transfer belt 12 in the approximate center of the apparatus main body 200, an image forming unit 7 having a photoreceptor 1 above it, and a conveyance path having a sheet reversing path 36 below. In addition, a paper feed unit having a paper feed cassette 31 is provided below the paper reversing path 36.

In the image forming unit 7, an electrostatic latent image based on image data input from an external device such as a personal computer is written by the optical writing device 3 on the photoreceptor 1 uniformly charged by the charging device 2. A toner is attached to the electrostatic latent image by the developing device 4 to form a toner image.
As the toner image formed on the photoreceptor 1 rotates, the toner image is conveyed to a primary transfer region formed by the photoreceptor 1 and the intermediate transfer belt 12, and is provided on the inner peripheral surface side of the intermediate transfer belt 12. Primary transfer is performed on the intermediate transfer belt 12 by a primary transfer roller 13 as a secondary transfer unit.
Thereafter, the repulsive rollers 15 and 2 are passed through the intermediate transfer belt 12 as the intermediate transfer belt 12 rotated around the repulsive roller 15 which is also a plurality of stretching rollers and secondary transfer backup rollers in the clockwise direction in the drawing. It is conveyed to the secondary transfer area facing the next transfer device 50.

  In the intermediate transfer belt 12, in the primary transfer region, a primary transfer bias is applied to a primary transfer roller 13 that is a transfer bias application member, and a toner image on the photoreceptor 1 is primarily transferred onto the intermediate transfer belt 12. The Further, a repulsive roller 15 is disposed as a transfer bias applying member in the secondary transfer area, and the repulsive roller 15 applies a secondary transfer bias in a state where the repulsive roller 15 is in contact with the inner peripheral surface of the intermediate transfer belt 12. It has become.

The step of transferring the toner image from the photoreceptor 1 onto the intermediate transfer belt 12 is referred to as a primary transfer step, and the step of transferring the toner image from the intermediate transfer belt 12 onto the paper P is referred to as a secondary transfer step.
In the present embodiment, the secondary transfer region in which the secondary transfer process is performed includes a foaming roller 51 and a repulsive roller 15 which are secondary transfer rollers formed of a foaming roller as a transfer unit that presses the intermediate transfer belt 12 toward the repulsive roller 15. A configured secondary transfer nip portion is provided. The image is transferred onto the paper P at the secondary transfer nip portion, and the recording paper on which an unfixed image is placed is conveyed to the fixing device 18 by the conveyance belt 17 provided downstream of the secondary transfer process. The toner image is fixed.
Note that the sheet P conveyed from the paper feed cassette 31 and waiting at the position of the registration roller 21 on the intermediate transfer belt 12 conveyed to the secondary transfer nip is synchronized with the timing of the toner image. The secondary transfer is performed by being conveyed toward the portion.

The paper P on which the toner image is fixed is discharged from a paper discharge tray 33 which is a discharge portion provided outside the apparatus main body 200. Alternatively, when forming an image on the back surface of the paper P during double-sided image formation, the front and back of the paper P are reversed and transported again to the double-sided image forming paper reversing path 36 that is transported to the registration roller 21. Image formation is performed.
Here, in FIG. 1, a paper feed path 35, a paper feed roller 43, and a manual feed tray 34 for manual feeding are disposed on the right side of the registration roller 21 and the transport roller 22.
The transfer residual toner remaining on the photoreceptor 1 after the primary transfer is removed by the photoreceptor cleaning device 6 to prepare for the next image formation. Similarly, untransferred toner remaining on the intermediate transfer belt 12 is removed by a belt cleaning device (not shown) to prepare for the next image formation.

  Further, in the secondary transfer device 50 shown in FIG. 2, the toner attached to the foaming roller 51 is cleaned by applying a cleaning bias from the repulsive roller 15 to the foaming roller 51.

  The secondary transfer nip portion of the secondary transfer region is provided on the transport path of the paper P, and on the upstream side of the transport path, a registration roller 21 for setting the registration timing of the paper P and a paper feed roller of the paper feed section A conveyance roller 22 that further feeds out the paper P conveyed from 41 is disposed.

In such a transfer type image forming apparatus, when the thickness and weight of the paper entering the transfer nip portion of the transfer area and the state of the paper curl change, the leading edge of the paper when entering the transfer nip portion Various problems occur due to the different postures.
For example, if the paper type of the paper entering the transfer nip changes, the basis weight decreases, the thickness of the paper P decreases, or the weight decreases, the stiffness of the paper becomes weaker. There is a case where the posture of the leading edge of the entering paper changes so as to hang downward. Similarly, when the weight of the paper changes due to changes in the temperature or humidity environment in the image forming apparatus or the paper, the posture of the leading edge of the paper entering the transfer nip portion is lowered. It may change to hang down.
On the other hand, for paper with both ends in the paper transport direction curled upward, the posture of the leading edge of the paper entering the transfer nip changes so as to warp upward, and for paper with both ends curled downward, the transfer area The position of the leading end of the recording material entering the recording medium changes so as to hang downward.

When the posture of the leading end portion of the paper P entering the transfer nip portion of the transfer area is changed as described above, for example, a foam roller is used as a secondary transfer roller of a transfer device that forms an intermediate transfer belt and a secondary transfer nip portion. When using, the following problems may occur.
A phenomenon in which the toner remaining on the surface of the foaming roller or the toner extruded from the foaming layer near the surface of the foaming roller due to the collision of the paper P adheres to the edge surface of the recording material and becomes dirty, so-called edge contamination occurs. Resulting in.
Even if a foaming roller is not used as the transfer roller, the recording material may be directly collided with the image carrier or the transfer roller and the leading end of the recording material may be broken. In some cases, the recording material may be jammed in the transfer area.

In order to suppress the above problems, a transfer entrance guide plate for defining the direction of the sheet entering the secondary transfer nip portion is provided at a position immediately before the secondary transfer nip portion of the conveyance path. It is common.
The transfer entrance guide plate 71 shown in FIG. 2 may cause problems such as transfer blur depending on conditions such as accuracy, structure, and arrangement. Therefore, in order to maintain image quality, the transfer entrance guide plate 71 is accurately used. Proper design is required.
The function required for the transfer entrance guide plate 71 is a function of regulating the position where the paper P contacts the area of the secondary transfer nip portion. That is, the posture of the leading edge when the sheet P enters the area of the secondary transfer nip is regulated.

  Here, also in the secondary transfer device 50 of the present embodiment, by using the foam roller 51 as the secondary transfer unit, the cleaning mechanism for cleaning the secondary transfer roller and the lubricant applied to the secondary transfer roller can be eliminated. . Then, as described above, the bias cleaning for cleaning the toner attached to the foaming roller 51 by the cleaning bias from the repulsive roller 15 is performed.

However, in the configuration in which the transfer entrance guide plate 71 conventionally used as shown in FIG. 2 is fixedly provided, the leading edge of the paper P is conveyed to the foaming roller 51 side and directly collides with the foaming roller 51. The following phenomena may occur when touching. Without bias cleaning, the toner remaining in the foam layer near the surface layer of the foam roller 51 is pushed out and adheres to the edge surface on the leading end side of the paper P, or the toner remaining on the surface layer of the foam roller 51 adheres to the leading edge of the paper P. The phenomenon that it gets dirty by sticking to the side edge of the side occurs. So-called edge surface contamination occurs.
Therefore, in the printer 300 of this embodiment, when the paper P enters the secondary transfer nip portion, the transfer entrance guide plate 71 that restricts the posture of the leading end of the paper P is provided movably.
Hereinafter, the transfer inlet transport mechanism 60 that is movably provided with the transfer inlet guide plate 71 that is a feature of the present invention will be described in detail.

  In the transfer entrance transport mechanism 60 provided at the entrance of the secondary transfer nip portion of this embodiment, the transfer entrance guide plate 71 provided in the secondary transfer device 50 is configured to be movable as follows, and the sheet P is moved to the secondary transfer nip. The conveyance operation angle (tilt angle) at the time of guiding to the part is variable. Note that the transfer inlet transport mechanism 60 of the present embodiment includes a movable mechanism 70 that is an inclination angle changing unit that changes the inclination angle of the transfer inlet guide plate 71, and a detection unit 80 that detects the state of the paper P described later (FIG. 5). Reference).

As shown in FIG. 3, an eccentric cam 73 is provided so as to contact the lower part (back side) of the transfer inlet guide plate 71, the intermediate transfer belt 12, and the repulsive roller 15 that is in contact with the back side of the intermediate transfer belt 12. The conveyance operation angle to the transfer nip formed by the foaming roller 51 is variable.
In addition, a receiving member 72 is disposed below the transfer inlet guide plate 71 on the upstream side in the sheet conveying direction from the location where the eccentric cam 73 is in contact. By rotating the eccentric cam 73, the receiving member 72 is rotated. The transfer inlet guide plate 71 rotates about the rotation fulcrum.

By providing the movable mechanism 70 that rotatably supports the transfer entrance guide plate 71 in this way, the transfer entrance guide plate is prevented from contacting the edge surface (end surface) of the front end portion of the paper P toward the foaming roller 51. It is possible to regulate the posture of the leading end of the paper P by rotating the 71.
Therefore, by preventing the leading edge of the paper P from coming into contact with the foaming roller 51, it becomes possible to prevent the edge surface contamination as described above.
Further, by using the eccentric cam 73, the structure of the movable mechanism 70 can be simplified, and the transfer operation angle of the transfer inlet guide plate 71 can be changed with high accuracy.

Hereinafter, more specifically, control performed when the transfer entrance guide plate 71 is rotated will be described.
As shown in FIG. 5, a detection unit 80 is provided in the sheet feeding device 20 in which the registration roller 21 for setting the registration timing provided on the upstream side of the transfer entrance guide plate 71 in the sheet conveyance direction and the conveyance roller 22 are arranged. Is provided. The detection unit 80 includes a weight detection sensor 81 that is a sensor unit of a basis weight detection unit that detects the basis weight (weight) of the paper P.
Then, based on the weight of the paper P detected by the weight detection sensor 81, the basic weight (weight) of the paper P is calculated by the basic weight detection means (program) executed in the control unit (not shown), and the following three steps are performed. Detect as.

なお、上記した表１の値よりも図３、図５に記載した転写入口ガイド板７１の角度が大きいのは、各図の態様を分かり易くするために、誇張した結果である。 63 g / ^{m 2} or less is detected and thin paper and ^detects plain paper up to ^{63g / m 2 ~163g / m 2} , it detects the cardboard up to ^{163g / m 2 ~350g / m 2} . Then, the transfer operation angle of the transfer inlet guide plate 71 can be varied in three steps to the angles shown in Table 1, and the sheet P can be aimed at the repulsive roller 15 side of the secondary transfer nip without contacting the foaming roller 51. it can.

Note that the angle of the transfer entrance guide plate 71 shown in FIGS. 3 and 5 is larger than the values shown in Table 1 above, which is an exaggerated result for easy understanding of the mode of each figure.

Further, as shown in FIG. 5, the detection unit 80 provided in the paper feeding device 20 is provided with a distance sensor 82 which is a sensor unit of the curl amount detection means. Measure distance.
Based on the distance from the sensor position measured by the distance sensor 82 to the sheet P, the curl amount of the sheet P is calculated by a curl amount detection means (program) executed in a control unit (not shown), and the following three steps are performed. Detect as.
When the curl amount is 1 mm or less, the curl amount is small, when the curl amount is 1 mm to 3 mm, the curl amount is medium, and when the curl amount is 3 mm or more, the curl amount is large. Then, the transfer operation angle of the transfer inlet guide plate 71 can be varied in three steps to the angles shown in Table 1, and the sheet P can be aimed at the repulsive roller 15 side of the secondary transfer nip without contacting the foaming roller 51. it can.

The detection performed by each detection means and the change of the transport operation angle are performed at the following timing.
The basis weight detection means detects the weight of the paper P when a predetermined time has elapsed after the registration sensor 83 detects the leading edge of the paper P (when the leading edge of the paper P stops at the nip portion of the registration roller 21). Detection is performed by the detection sensor 81 to determine whether the paper is thin paper, plain paper, or thick paper.
The curl amount detection means detects the maximum value of the distance to the paper P detected by the distance sensor 82 within a predetermined time until the registration sensor 83 detects the leading edge of the paper P, and the curl amount is small. Determine whether medium or large.
The change timing of the conveyance operation angle of the transfer entrance guide plate 71 detects the basis weight and the curl amount of the paper P with the timing of detecting the leading edge of the paper P by the registration sensor 83 as a trigger. Then, after determining the sheet conditions such as the basis weight of the sheet P and the determination type of the curl amount, the conveyance operation angle of the transfer entrance guide plate 71 is changed.

As described above, by detecting the condition of the paper P detected by the basis weight detecting means and the curl amount detecting means (hereinafter referred to as paper conditions), the transfer entrance guide plate is used with the eccentric cam 73 under the detected paper conditions. The conveyance operation angle 71 can be varied.
For example, in the case of thin paper, since the stiffness of the paper P is weak, the secondary transfer nip portion that has passed through the transfer inlet guide plate 71 is conveyed while being bent toward the foaming roller 51 side. It is necessary to keep an angle.
Also, when the curl amount is large, it is easy to be transported to the repulsive roller 15 side of the secondary transfer nip, but because of the large curl amount, it is not transported to the secondary transfer nip and a jam occurs before the secondary transfer nip. there's a possibility that. In order to prevent this jamming, it is necessary to measure the curl amount and set the transfer operation angle of the transfer entrance guide plate 71 to the curl amount shown in Table 1.

Further, as shown in FIG. 4, a stepping motor 75 is mounted on the eccentric cam 73 of the movable mechanism 70 that moves the transfer inlet guide plate 71, and is connected to the cam shaft 74. The transfer operation angle of the transfer entrance guide plate 71 can be varied by controlling the sheet conditions detected by the basis weight detecting means and the curl amount detecting means.
Further, a resist sensor used for resist sensor control in the paper feeding device 20 shown in FIG. 5 is used as a trigger for timing to be controlled in accordance with the paper conditions detected by the basis weight detecting means and the curl amount detecting means. 83, the detection timing of the leading edge of the paper P can be set. In addition, when an optional scanner unit is added to the printer 300 and operated in the copier mode, etc., the edge of the paper P can be printed even in mixed loading by using the size control of the paper P set on the operation panel by the operator. Paper can be passed without getting dirty.

As described above, the following effects can be achieved by using the transfer inlet transport mechanism 60 of the present embodiment.
First, Table 1 shows the basis conditions of the paper P and the curl amount of paper P detected by the detecting means by the eccentric cam 73 provided at the lower part of the transfer inlet guide plate 71 and the transfer operation angle detected by each detecting means. It is changed by a value (angle) such as a tilt angle of the guide plate. By changing in this way, the edge surface of the leading end of the paper P can be prevented from contacting the foaming roller 51, and the occurrence of edge contamination of the paper P due to the toner remaining on the foaming roller 51 can be suppressed.
That is, by adopting the configuration of the present embodiment described above, the toner image is transferred to the sheet P at the secondary transfer nip portion without causing the edge of the sheet P to come into contact with the foaming roller 51 and causing the edge of the sheet to be stained. Next transfer can be performed.

  Further, the weight (basis weight) of the paper P detected by each sensor of the basis weight detecting means and the curl amount detecting means with the eccentric cam 73 provided at the lower part of the transfer entrance guide plate 71 and the conveyance operation angle of the transfer entrance guide plate 71. And the angle (curl amount) is changed to a specified angle. In this way, by changing the conveying operation angle of the transfer entrance guide plate 71 and guiding the paper P to the repulsive roller 15 side of the secondary transfer nip portion, the edge of the paper P is covered with the toner remaining on the foaming roller 51. Staining, that is, occurrence of edge contamination can be suppressed.

Further, a weight detection sensor 81 is provided in the paper feeding device 20 for setting the registration timing provided on the upstream side in the paper conveyance direction below the transfer entrance guide plate 71 shown in FIG. The basis weight is calculated based on the weight information of the paper P, and 63 g / m ² or less is detected as a thin paper. Then ^detects plain paper up to ^{63g / m 2 ~163g / m 2} , detects the cardboard up to ^{163g / m 2 ~350g / m 2} . Based on the detection result, the transfer inlet guide plate 71 is conveyed by the eccentric cam 73 to the secondary transfer nip portion by changing it to the angle shown in Table 1 in three steps, so that the paper P It is possible to suppress the occurrence of edge contamination.

  In addition, a distance sensor 82 is provided in the paper feeding device 20 for setting the registration timing provided on the upstream side in the paper conveyance direction below the transfer entrance guide plate 71 shown in FIG. 5, and the distance between the sensor position and the paper P is measured. Then, the sheet P is calculated based on the distance information. When the curl amount is 1 mm or less, the curl amount is small, when the curl amount is 1 mm to 3 mm, the curl amount is medium, and when the curl amount is 3 mm or more, the curl amount is large. Based on the detection result, the transfer inlet guide plate 71 is conveyed by the eccentric cam 73 to the secondary transfer nip portion by changing it to the angle shown in Table 1 in three steps, so that the paper P It is possible to suppress the occurrence of edge contamination.

  Further, the eccentric cam 73 provided at the lower part of the transfer inlet guide plate 71 shown in FIG. 4 is automatically controlled by the stepping motor 75 in accordance with the paper conditions detected by the basis weight detecting means and the curl amount detecting means. The conveyance operation angle of the inlet guide plate 71 is varied. By automatically controlling in this way and transporting the paper P toward the secondary transfer nip portion in accordance with the paper conditions, the edge of the paper P is stained with the toner remaining on the foaming roller 51, that is, the edge surface is dirty. Occurrence can be suppressed.

  Further, by using the paper condition detected by the basis weight detecting means and the curl amount detecting means and the detection timing of the paper leading edge of the registration sensor 83 performing the registration sensor control in the paper feeding device 20 shown in FIG. The following effects can be achieved. The following effects can be obtained even in mixed loading in which the sizes of the sheets P to be continuously passed are different. Even when the paper P is mixed by size, the transfer operation angle of the transfer inlet guide plate 71 is changed to convey the paper P, so that the edge of the paper P is stained with the toner remaining on the foaming roller 51. That is, the occurrence of edge contamination can be suppressed.

  By using the size control of the paper P set by the operator on the operation panel, such as when operating in the copier mode, the following effects can be achieved even when the paper P is fed by size of the mixed paper P. Can do. By conveying the sheet P while changing the conveying operation angle of the transfer entrance guide plate 71, it is possible to suppress the edge of the sheet P from being stained with the toner remaining on the foaming roller 51, that is, the occurrence of edge contamination.

What has been described above is merely an example, and the present invention has a specific effect for each of the following modes.
(Aspect A)
A transfer area where an image carrier such as an intermediate transfer belt 12 carrying a toner image and a transfer means such as a foam roller 51 for transferring the toner image carried on the image carrier onto a recording material such as paper P are opposed to each other. In a transfer inlet transport mechanism such as a transfer inlet transport mechanism 60 that guides the recording material to the entrance of the recording material, a transfer such as a transfer entrance guide plate 71 that guides the recording material while regulating the posture from below to the entrance of the transfer region. A grammage detecting means for detecting the grammage of the recording material, and an end portion of the recording material, comprising an entrance guide plate and an inclination angle changing means such as a movable mechanism 70 for changing the tilt angle of the transfer entrance guide plate; At least one of a curl amount detecting means for detecting the curl amount of the ink, and the inclination angle of the transfer inlet guide plate is changed by the inclination angle changing means based on a detection result of the one detection means. It is an.
According to this, as described in the present embodiment, the following effects can be achieved. Stabilizes the posture of the leading edge of the recording material that enters the transfer area, such as the secondary transfer nip, regardless of the thickness, weight, curl, etc. of the recording material, and suppresses the occurrence of problems caused by posture changes. It is possible to provide a transfer entrance conveyance mechanism that can be used.

(Aspect B)
In (Aspect A), the grammage includes both a grammage detecting means for detecting the grammage of the recording material such as paper P and a curl amount detecting means for detecting the curl amount of the leading end of the recording material, and the grammage Based on the detection results of the detection means and the curl amount detection means, the inclination angle of the transfer inlet guide plate such as the transfer inlet guide plate 71 is changed by the inclination angle changing means such as the movable mechanism 70. Inlet transport mechanism.
According to this, as described in the present embodiment, the following effects can be achieved. Stabilizes the posture of the leading edge of the recording material that enters the transfer area, such as the secondary transfer nip, regardless of the thickness, weight, curl, etc. of the recording material, and suppresses the occurrence of problems caused by posture changes. It is possible to provide a transfer entrance conveyance mechanism that can be used.

(Aspect C)
In (Aspect A) or (Aspect B), the image carrier is an intermediate transfer belt such as an intermediate transfer belt 12 carrying a toner image, and the transfer means is stretched around a repulsive roller such as a repulsive roller 15. Further, the image forming apparatus includes a secondary transfer roller such as a foam roller 51 including a foam roller that forms a secondary transfer nip portion with the intermediate transfer belt.
According to this, as described in the present embodiment, the toner image is recorded at the secondary transfer nip portion without causing the edge surface of the recording material such as the paper P to come into contact with the foaming roller and causing the edge surface to become dirty. Secondary transfer.

(Aspect D)
In any one of (Aspect A) to (Aspect C), the inclination angle changing means such as the movable mechanism 70 is provided with an eccentric cam 73 provided so as to contact a lower portion of the transfer inlet guide plate such as the transfer inlet guide plate 71. The inclination angle of the transfer inlet guide plate is changed by rotating an eccentric cam.
According to this, as described in the present embodiment, the configuration of the inclination angle changing means can be simplified, and the transfer operation angle of the transfer inlet guide plate can be changed with high accuracy.

(Aspect E)
In (Aspect D), the inclination angle changing means such as the movable mechanism 70 has a tapping motor such as a stepping motor 75, and the recording material condition derived from the detection results of the basis weight detecting means and the curl amount detecting means. Based on the above, the stepping motor is controlled to change the rotation angle of the eccentric cam such as the eccentric cam 73.
According to this, as described in the present embodiment, the transfer entrance guide plate 71 and the like are automatically controlled by the stepping motor in accordance with the sheet condition detected by the basis weight detection unit and the curl amount detection unit. The transfer operation angle of the transfer entrance guide plate is varied. In this way, the recording material such as paper P is transported toward the secondary transfer nip portion according to the paper conditions, so that the toner remaining on the transfer means such as the foaming roller 51 is covered with the cover surface of the recording material. It is possible to suppress the occurrence of contamination on the edge surface, that is, the edge surface.

(Aspect F)
In any one of (Aspect A) to (Aspect E), the basis weight detection means includes the paper P or the like provided on the upstream side of the transfer inlet guide plate such as the transfer inlet guide plate 71 in the recording material conveyance direction. There is a weight sensor such as a weight detection sensor 81 for detecting the weight of the recording material in a resist conveyance section such as a paper feeding device 20 for setting the registration timing of the recording material to the transfer area, and the detection result of the weight sensor. Based on the above, the basis weight of the recording material is detected.
According to this, as described in the present embodiment, the basis weight is calculated based on the weight information of the recording material, and for example, 63 g / m ² or less is detected as thin paper. Then ^detects plain paper up to ^{63g / m 2 ~163g / m 2} , detects the cardboard up to ^{163g / m 2 ~350g / m 2} . Based on the detection result, the transfer entrance guide plate is conveyed by the eccentric cam such as the eccentric cam 73 to the secondary transfer nip portion by varying the angle shown in Table 1 in three steps. By doing so, it is possible to suppress the edge of the recording material from being stained with the toner remaining on the foaming roller such as the foaming roller 51, that is, the occurrence of edge contamination.

(Aspect G)
In any one of (Aspect A) to (Aspect F), the curl amount detecting means is a sheet P or the like provided on the upstream side in the recording material conveyance direction of the transfer inlet guide plate such as the transfer inlet guide plate 71. A registration sensor such as a distance sensor 82 that detects a distance from the sensor position to the recording material is provided in a registration conveyance unit such as a paper feeding device 20 that sets a registration timing of the recording material to the transfer region, and a recording distance The curl amount is detected based on the detection result of the sensor.
According to this, as described in the present embodiment, the following effects can be achieved. For example, when the curl amount is 1 mm or less, the curl amount is small, when the curl amount is 1 mm to 3 mm, the curl amount is medium, and when the curl amount is 3 mm or more, the curl amount is large. Based on the detection result, the transfer entrance guide plate is conveyed by the eccentric cam such as the eccentric cam 73 to the secondary transfer nip portion by varying the angle shown in Table 1 in three steps. By doing so, it is possible to suppress the edge of the recording material from being stained with the toner remaining on the foaming roller such as the foaming roller 51, that is, the occurrence of edge contamination.

(Aspect H)
In any one of (Aspect A) to (Aspect G), the change of the inclination angle of the transfer inlet guide plate such as the transfer inlet guide plate 71 by the inclination angle changing means such as the movable mechanism 70 is recorded on the inlet guide plate. It is characterized in that it is triggered by the detection timing of the recording material such as paper P by a registration sensor such as a registration sensor 83 provided in a registration conveyance section such as a paper feeding device 20 provided upstream in the material conveyance direction. It is.
According to this, as described in the present embodiment, the following effects can be achieved even when the recording materials to be continuously passed are different in size. Even in the case of passing the recording materials by size when mixed, the recording material is conveyed by changing the conveying operation angle of the transfer entrance guide plate, so that the toner remaining on the foaming roller such as the foaming roller 51 can be used to remove the edge of the recording material. Staining, that is, occurrence of edge contamination can be suppressed.

(Aspect I)
In any one of (Aspect A) to (Aspect H), the recording material such as paper P input on an operation panel of an image forming apparatus such as a printer 300 including the transfer entrance guide mechanism 60 or the like. On the basis of the size control, the inclination angle changing means such as the movable mechanism 70 changes the inclination angle of the transfer inlet guide plate such as the transfer inlet guide plate 71.
According to this, as described in the present embodiment, when operating in the copying machine mode, the size control of the recording material set by the operator on the operation panel is used, so that the recording material can be classified according to the size at the time of mixed loading. The following effects can also be achieved in this paper passing. By transporting the recording material while changing the transport operation angle of the transfer entrance guide plate, it is possible to suppress the edge of the recording material from being contaminated with the toner remaining on the foaming roller such as the foaming roller 51, that is, the occurrence of the surface contamination. it can.

(Aspect J)
An image carrier such as an intermediate transfer belt 12 carrying a toner image; transfer means such as a foam roller 51 for transferring a toner image carried on the image carrier onto a recording material such as paper P; and the image carrier In an image forming apparatus such as a printer 300 provided with a transfer inlet guide mechanism such as a transfer inlet transport mechanism 60 for guiding the recording material at an entrance of a transfer region opposed to the transfer unit, A transfer entrance guide mechanism according to any one of A) to (Aspect I) is provided.
According to this, as described in the present embodiment, it is possible to provide an image forming apparatus that can achieve the same effects as the transfer entrance guide mechanism of any one of (Aspect A) to (Aspect I).

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Charging device 3 Optical writing device 4 Developing device 6 Photoconductor cleaning device 7 Image forming unit 10 Transfer unit 12 Intermediate transfer belt 13 Primary transfer roller 15 Repulsive roller 17 Conveying belt 18 Fixing device 20 Paper feeding device 21 Registration roller 22 Transport roller 31 Paper feed cassette 33 Paper discharge tray 34 Manual feed tray 35 Paper feed path 36 Paper reversing path 41 Paper feed roller 43 Paper feed roller 50 Secondary transfer device 51 Foam roller 60 Transfer inlet transport mechanism 70 Movable mechanism 71 Transfer inlet guide Plate 73 Eccentric cam 74 Eccentric cam shaft 75 Stepping motor 80 Detection unit 81 Weight detection sensor 82 Distance sensor 83 Registration sensor 200 Main body 300 Printer P Paper

Claims (10)

In a transfer inlet transport mechanism for guiding the recording material to an entrance of a transfer region where an image carrier that carries the toner image and a transfer unit that transfers the toner image carried on the image carrier onto the recording material face each other. ,
A transfer inlet guide plate that guides the recording material while restricting a posture from below to the entrance of the transfer region; and an inclination angle changing unit that changes an inclination angle of the transfer inlet guide plate,
Having at least one of a basis weight detection means for detecting the basis weight of the recording material and a curl amount detection means for detecting a curl amount at the tip of the recording material;
The transfer inlet transport mechanism, wherein the inclination angle changing means changes the inclination angle of the transfer inlet guide plate based on the detection result of the one detection means. The transfer inlet transport mechanism according to claim 1,
Having both a basis weight detection means for detecting the basis weight of the recording material and a curl amount detection means for detecting the curl amount at the tip of the recording material;
A transfer inlet transport mechanism, wherein the inclination angle changing means changes the inclination angle of the transfer inlet guide plate based on detection results of the basis weight detection means and the curl amount detection means. The transfer inlet transport mechanism according to claim 1 or 2,
The image carrier is an intermediate transfer belt carrying a toner image;
The transfer entrance transport mechanism, wherein the transfer means includes a secondary transfer roller including a foam roller that forms a secondary transfer nip portion and the intermediate transfer belt stretched around a repulsive roller. The transfer inlet transport mechanism according to any one of claims 1 to 3,
The transfer inlet transport mechanism characterized in that the tilt angle changing means changes the tilt angle of the transfer inlet guide plate by rotating an eccentric cam provided so as to be in contact with the lower portion of the transfer inlet guide plate. In the transfer inlet transport mechanism according to claim 4,
The inclination angle changing means has a tapping motor,
A transfer inlet transport mechanism, wherein the rotation angle of the eccentric cam is changed by controlling the stepping motor based on a recording material condition derived from detection results of the basis weight detection means and the curl amount detection means. The transfer inlet transport mechanism according to any one of claims 1 to 5,
The basis weight detection means detects the weight of the recording material in a resist conveyance portion that sets a registration timing of the recording material to the transfer area provided upstream of the transfer inlet guide plate in the recording material conveyance direction. A weight sensor to
A transfer inlet transport mechanism that detects a basis weight of the recording material based on a detection result of the weight sensor. The transfer inlet transport mechanism according to any one of claims 1 to 6,
The curl amount detection means is provided between the sensor position and the recording material in a resist conveyance portion that sets a registration timing of the recording material to the transfer area provided upstream of the transfer inlet guide plate in the recording material conveyance direction. Having a distance sensor to detect the distance;
A transfer inlet transport mechanism that detects a curl amount based on a detection result of a recording distance sensor. In the transfer inlet transport mechanism according to any one of claims 1 to 7,
The timing at which the recording material is detected by a resist sensor provided in a resist conveyance unit provided upstream of the entrance guide plate in the recording material conveyance direction is changed by the inclination angle changing means. A transfer inlet transport mechanism that is used as a trigger. The transfer entrance guide mechanism according to any one of claims 1 to 8,
The inclination angle changing means changes the inclination angle of the transfer inlet guide plate based on the size control of the recording material input on the operation panel of the image forming apparatus provided with the transfer inlet guide mechanism. A transfer inlet transport mechanism. An image carrier that carries a toner image, a transfer unit that transfers the toner image carried on the image carrier onto a recording material, and an entrance of a transfer region where the image carrier and the transfer unit face each other at the recording material In an image forming apparatus provided with a transfer entrance guide mechanism for guiding
An image forming apparatus comprising the transfer inlet guide mechanism according to claim 1 as the transfer inlet guide mechanism.

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