JP3918463B2 - Paper conveying apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly, to a sheet conveying apparatus used in the image forming apparatus.
[0002]
[Prior art]
In general, in an image forming apparatus such as a copying machine, when a sheet to be image-formed is conveyed, the sheet being conveyed may be displaced due to various factors. In such a case, if the sheet is sent to the image forming processing position with the position shifted, the image is formed in a state shifted from the sheet.
[0003]
For this reason, a paper conveyance device used in the image forming apparatus incorporates a paper correction mechanism that corrects the positional deviation of the paper being conveyed. As a correction method using this paper correction mechanism, there is known a correction method based on a so-called side registration (hereinafter, abbreviated as a side registration) standard that corrects a positional deviation of a paper with reference to a side edge of the paper being conveyed. .
[0004]
In the paper transport device adopting the above correction method, a side reference guide is provided on one side of the paper transport path in parallel with the paper transport direction, and a skew roller is disposed on the paper transport path. Of the paper is moved closer to the side reference guide, the side edge of the paper is abutted against the side reference guide, and the side registration (position deviation of the paper side edge in the direction orthogonal to the conveyance direction) and side skew (paper side with respect to the conveyance direction) Both edges are corrected.
[0005]
In this type of paper transport device, when the side edge of the paper is abutted against the side reference guide by the skew roller, a certain force acts between the paper and the skew roller (contact portion) to slip. By using this slip phenomenon, the side edge of the paper is caused to travel along the side reference guide.
[0006]
At that time, in order to properly correct the misalignment (side registration, side skew, etc.) of the paper, the pressing force of the paper against the side reference guide is stabilized while the side edge of the paper is abutted against the side reference guide. It becomes important. This is because if the paper pressing force is too strong, the paper will buckle, loop, etc., causing correction accuracy deterioration and jamming. If the paper pressing force is too weak, the side edge of the paper will be This is because it is impossible to properly follow the reference guide, resulting in a defective correction.
[0007]
[Problems to be solved by the invention]
However, the coefficient of friction between the skew roller and the paper changes due to various factors such as environment such as temperature and humidity, paper quality, presence / absence of toner fixing, adhesion of image fixing oil (fuser oil), and adhesion of paper dust. As a result, the pressing force of the paper against the side reference guide also changes slightly. For this reason, there is a possibility that the above-mentioned problems may be caused by excessive or insufficient pressing force.
[0008]
Therefore, regarding correction of the positional deviation of the sheet using the skew roller, for example, Japanese Patent Laid-Open No. 5-246484 discloses a technique for changing the nip pressure of the skew roller, Correspondingly, it is practically impossible to appropriately control the nip pressure of the skew roller.
[0009]
[Means for Solving the Problems]
The paper transport device according to the present invention is a paper-side end positioning unit provided on one side of the paper transport path in parallel with the paper transport direction, and rotates in contact with the paper transported through the paper transport path. The side edge of the paper is abutted against the paper side edge positioning means, and the contact portion against the paper is elastically deformed by the reaction force caused by the abutting against the paper side edge positioning means. The width adjusting means is configured to be obtained. The width adjusting means is configured by using a skew roller having an outer peripheral portion as a contact portion, and a plurality of contact portions are arranged in parallel in the rotation axis direction of the skew roller. By forming a plurality of slits that cut in the small diameter direction of the skew roller at each contact portion, each contact portion is divided into a plurality of portions in the circumferential direction of the skew roller, and a plurality of contact portions arranged in parallel are arranged. Among them, the phase of the division position by the plurality of slits formed in one contact portion and the division position by the plurality of slits formed in the other contact portion are set to be shifted from each other in the circumferential direction of the skew roller. ing. An image forming apparatus according to the present invention includes the sheet conveying device having the above-described configuration.
[0010]
In the sheet conveying apparatus having the above-described configuration and the image forming apparatus including the sheet conveying apparatus, the reaction force generated by the abutting is in contact with the width aligning unit in a state where the side end of the sheet is abutted against the sheet side end positioning unit by the width aligning unit. By acting on the part and receiving the reaction force, the contact part is elastically deformed, whereby a pressing force of the sheet against the side reference guide is obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a schematic diagram showing the overall configuration of a full-color image forming apparatus to which the present invention is applied. The illustrated full-color image forming apparatus 1 is mainly composed of an image reading unit 2, an image forming unit 3, and a sheet conveying device 4.
[0013]
The image reading unit 2 reads an image of a document set on a transparent document table (platen glass). The image reading unit 2 includes, for example, an optical scanning system including a lamp, a mirror, a carriage, and the like, a lens system that forms an optical image read and scanned by the optical scanning system, and an optical image formed by the lens system. And an image reading sensor (for example, a three-line CCD sensor) that receives the light and converts it into an electrical signal.
[0014]
The image forming unit 3 includes four photosensitive drums 5, 6, 7, and 8 corresponding to K (black), Y (yellow), M (magenta), and C (cyan), and each photosensitive drum. A four-tandem structure including four corresponding primary transfer rollers 9, 10, 11, 12, an intermediate transfer belt 13, a secondary transfer roller 14, a vacuum transport unit 15, and a fixing device 16 is provided. ing.
[0015]
Around each of the photosensitive drums 5, 6, 7, and 8, a charger, a laser writing device (laser ROS), a developing device, a cleaner, and the like are arranged. The charging device uniformly charges the surface of the photosensitive drum, and the laser writing device forms an electrostatic latent image on the surface of the photosensitive drum charged by the charging device by laser irradiation. The developing unit supplies toner as a developer to the surface of the photosensitive drum to visualize (develop) the electrostatic latent image to form a toner image, and the cleaner is unnecessary to remain on the photosensitive drum. It removes toner.
[0016]
On the other hand, the primary transfer rollers 9, 10, 11, and 12 are arranged in opposition to each other in the vicinity of the corresponding photosensitive drums 5, 6, 7, and 8 via the intermediate transfer belt 13. . These primary transfer rollers 9, 10, 11, and 12 transfer (primary transfer) the toner images formed on the photosensitive drums 5, 6, 7, and 8 to the intermediate transfer belt 13 as described above. . The intermediate transfer belt 13 is stretched in a loop by a plurality of (five in the illustrated example) belt support rollers.
[0017]
The secondary transfer roller 14 is disposed to face the intermediate transfer belt 13. The secondary transfer roller 14 transfers (secondary transfer) the toner image formed on the intermediate transfer belt 13 to a sheet (sheet) as described above, and the transfer position (secondary transfer position) of the toner image. Is the image forming processing position in the image forming unit 3. The vacuum conveyance unit 15 conveys the sheet on which the toner image is transferred by the secondary transfer roller 14 to the fixing device 16. The fixing device 16 fixes the toner image on the paper by heating and pressing.
[0018]
On the other hand, the paper transport device 4 uses the paper in the tray selected by the user operation or the automatic selection function from among the papers stored in the first tray 17, the second tray 18, and the third tray 19. Each sheet of the selected tray is conveyed by a predetermined route. In the vicinity of each of the trays 17, 18, 19, corresponding delivery rollers 20, 21, 22 are disposed. Each of the delivery rollers 20, 21, and 22 feeds the paper to the downstream side in the paper transport direction by pinching (niping) the called paper separately from the corresponding trays 17, 18, and 19 respectively. is there. In addition, an operation panel 23 operated by a user is provided in the vicinity of the image reading unit 2.
[0019]
Here, a series of paper transport paths R1 to R5 from the paper feed positions by the feed rollers 20, 21, and 22 to the discharge tray 24 via the image forming processing position in the image forming unit 3 are respectively provided. Rollers for conveying the paper are provided as appropriate. The paper stored in the first tray 17 is sent out by the feed roller 20 and then sent to the merging transport unit 25 via the first paper transport path R1. In addition, the paper stored in the second tray 18 is sent out by the feed roller 21 and then sent to the merging transport unit 25 via the first paper transport path R1. On the other hand, the paper stored in the third tray 19 is sent directly to the merging and conveying unit 25 by the delivery roller 22.
[0020]
The sheet sent to the merging / conveying section 25 is sent to the image forming processing position of the image forming section 3 via the second sheet conveying path R2. Further, the sheet that has passed the image forming processing position is sent to the fixing device 16 by the vacuum conveyance unit 15 and then discharged to the discharge tray 24 via the third sheet conveyance path R3. On the other hand, the paper on which images are formed on both sides (the first side and the second side) passes through the fixing device 16 and then is sent to the double-side reversing unit 28 via the fourth paper transport path R4. Then, after being turned upside down, the paper is fed again into the merging and conveying unit 25 via the fifth sheet conveying path R5.
[0021]
In such sheet conveyance paths R1 to R5, a sheet correction unit 26 and a registration roller 27 are disposed in the second sheet conveyance path R2. The paper correction unit 26 is a part that corrects the side skew and side lesbian of the paper conveyed along the second paper conveyance path R2. The configuration of the paper correction unit 26 will be described later. The registration roller 27 is composed of a pair of rollers that are held in pressure contact with each other. The sheet is sandwiched between the pair of rollers, and the sheet is fed to the image forming processing position by the rotation of the roller. .
[0022]
When the sheet is fed by the registration roller 27, the timing of arrival of the sheet with respect to the image forming process is adjusted by a timing adjusting unit (not shown). The timing adjustment unit varies the sheet conveyance speed by the registration roller 27 based on the timing at which a registration sensor (not shown) provided in front (upstream side) of the registration roller 27 detects the passage of the sheet, thereby In accordance with the arrival timing of the toner image at the formation processing position, the arrival timing of the paper for the image formation processing is adjusted.
[0023]
In addition, curl correction units 29 and 30 are provided in the paper transport paths R3 and R5, respectively. Each of the curl correcting units 29 and 30 is for correcting the curling of the paper that occurs when the fixing device 16 fixes the toner image.
[0024]
Next, the operation of the full color image forming apparatus 1 having the above configuration will be described. First, when an image of a document is read by the image reading unit 2, a toner image is formed by the image forming unit 3 based on an image signal obtained thereby. In this image forming unit 3, while rotating the four photosensitive drums 3, 4, 5, and 6, the corresponding photosensitive drums 5, 6 are respectively charged by the corresponding charger, laser writing device (laser ROS), and developing unit. , 7 and 8, toner images of K, Y, M, and C are sequentially formed. The toner images of the respective colors formed in this way are sequentially transferred onto the intermediate transfer belt 13 by the primary transfer rollers 9, 10, 11, and 12. As a result, a multicolor (full color) toner image in which four color toners are superimposed is formed on the intermediate transfer belt 13. The toner image formed on the intermediate transfer belt 13 in this way is carried on the intermediate transfer belt 13 and sent to the image forming processing position (secondary transfer position).
[0025]
On the other hand, the tray paper selected by the user using the operation panel 23 or the tray paper selected by the automatic selection function is sent by the registration roller 27 in accordance with the timing at which the toner image reaches the image forming processing position. For example, if the tray selected as described above is the first tray 17, the sheet fed by the feed roller 20 is sent to the merging / conveying unit 25 via the first sheet conveying path R1, and further The sheet is fed to the image forming processing position by the registration roller 27 via the second sheet conveyance path R2.
[0026]
As a result, the toner image (full color image) carried on the intermediate transfer belt 13 is collectively transferred (secondary transfer) onto the sheet by the secondary transfer roller 14 at the image forming processing position of the image forming unit 3. Thereafter, the sheet is sent to the fixing device 16 by the vacuum conveyance unit 15, where the toner image is fixed, and then discharged to the discharge tray 24 via the third sheet conveyance path R3.
[0027]
However, the paper on which the image is formed on both sides is sent to the double-side reversing unit 28 via the fourth paper conveyance path R4, and is turned upside down and sent to the fifth paper conveyance path R5. Thereafter, the double-sided copy paper is conveyed along the fifth paper conveyance path R <b> 5, and then the double-sided copy paper is adjusted in timing by the rotation of the feed roller 31 and sent again to the merging and conveying unit 25. Thereafter, after the toner image is transferred and fixed on the paper as described above, the paper is discharged to the discharge tray 24 via the third paper transport path R3.
[0028]
FIG. 2 is a schematic plan view showing the configuration of the paper correction unit 26 that is a main part of the paper transport device 4 according to the embodiment of the present invention. In FIG. 2, a plurality of (three in the illustrated example) skew rollers 32 are provided in order from the upstream side to the downstream side in the sheet conveyance direction Y. These skew rollers 32 are arranged so as to be inclined by a predetermined angle with respect to the paper transport direction Y, respectively. Each skew roller 32 is paired with a lower pinch roller (not shown).
[0029]
Each of the skew rollers 32 paired up and down in this manner nips (holds) the paper 33 with a biasing force of a biasing means (spring or the like) (not shown), and rotates in this nip state, so that it is on the paper transport path. Thus, a conveying force is applied to the sheet 33. The sheet 33 is fed in the oblique direction K in response to this conveying force.
[0030]
On the other hand, a side reference guide 34 is arranged in parallel with the transport direction Y on one side (right side in the drawing) of the paper transport path through which the paper 33 is transported. The side reference guide 34 constitutes a sheet side edge positioning unit, and integrally includes a reference surface 35 parallel to the transport direction Y. On the other hand, each of the skew rollers 32 brings the paper 33 conveyed in order from the upstream side to the side reference guide 34 side, and pushes the side edge of the paper 33 against the reference surface 35 of the side reference guide 34. This constitutes a width-shifting means.
[0031]
Here, the sheet conveying apparatus according to the present embodiment is characterized by the skew roller 32 that constitutes the width adjusting means. This characteristic portion will be described with reference to FIG. 3 while comparing it with the roller structure of a conventional paper conveying apparatus. FIG. 3A shows a skew roller used in a conventional paper transport device, and FIG. 3B shows a skew roller used in the paper transport device of this embodiment.
[0032]
First, the skew roller 51 shown in FIG. 3A is attached to a rotating shaft 52 that rotates using a motor or the like as a drive source. In this attached state, the skew roller 51 rotates integrally with the rotary shaft 52 by a drive source such as a motor. The outer shape of the skew roller 51 is circular when viewed from the direction of the rotation axis (left and right direction in FIG. 3). The skew roller 51 nips a sheet with a pinch roller (not shown) at the outer peripheral portion 53, and rotates the sheet in this nip state, thereby feeding the sheet obliquely.
[0033]
On the other hand, the skew roller 32 shown in FIG. 3B is also attached to a rotating shaft 36 that rotates using a motor or the like as a driving source, and is configured to rotate integrally with the rotating shaft 36. Further, the outer shape of the skew roller 32 is also circular when viewed from the rotation axis direction, and the paper 33 is obliquely fed by rotating the outer periphery 37 while the paper 33 is nipped between the pinch rollers (not shown). It has a configuration. Therefore, the outer peripheral portion 37 of the skew roller 32 comes into contact with the paper surface of the paper 33.
[0034]
The skew roller 51 and the skew roller 32 are both made of a rubber-like elastic body (rubber material), but the roller thicknesses Ta and Tb in the rotation axis direction are greatly different. That is, the skew roller 51 is relatively thick and has a structure in which contact with the paper is wide, whereas the skew roller 32 is thinner than the skew roller 51 (Tb <Ta). ), The contact with the paper is narrow.
[0035]
As described above, the skew rollers 51 and 32 exhibit different elastic characteristics due to the difference in the roller thickness in the rotation axis direction. That is, when an external force F in the rotation axis direction is applied to each of the skew rollers 51 and 32, the outer periphery (contact portion with the sheet) 53 of the skew roller 51 is difficult to elastically deform with respect to the external force F. In contrast, the skew roller 32 can easily elastically deform the outer peripheral portion (contact portion with the paper) 37 with respect to the external force F.
[0036]
The thickness Tb of the skew roller 32 is such that the outer peripheral portion 37 (the contact portion with the paper 33) is elastically deformed by a reaction force when the skew roller 32 abuts the side edge of the paper 33 against the side reference guide 34. Is set to be able to.
[0037]
Further, the outer peripheral edge of the skew roller 32 is cut out in an R shape. By providing such an R-shaped cutout, as shown in FIG. 4A, when the outer peripheral portion 37 of the skew roller 32 is elastically deformed, the outer diameter φ1 of the skew roller 32 before the deformation is obtained. And the apparent outer diameter φ1 of the skew roller 32 after the deformation can be kept constant. For this reason, the peripheral speed of the rotating skew roller 32 does not change, and the sheet 33 can be conveyed without fluctuation in speed.
[0038]
On the other hand, when the R-shaped notch is not provided, as shown in FIG. 4B, when the outer peripheral portion 37 ′ of the skew roller 32 ′ is elastically deformed, the skew roller before deformation is deformed. The apparent outer diameter φ2 of the skew roller 32 ′ after deformation becomes larger than the outer diameter φ1 of 32 ′. Therefore, the peripheral speed of the rotating skew roller 32 ′ changes, and a speed difference occurs in the conveyance of the paper 33. As a result, the paper is pulled or loosened between the three skew rollers 32, and the paper may be damaged.
[0039]
Therefore, in order to avoid such problems, it is an effective means to cut out the outer peripheral edge portion of the skew roller 32 into an R shape. The cutout shape is not limited to the R shape described above, and may be a tapered shape in which the outer peripheral edge of the skew roller 32 is chamfered.
[0040]
Next, a paper correction operation by the paper transport device according to the embodiment of the present invention will be described. First, the sheet 33 sent from the upstream side in the transport direction Y is nipped in order by each skew roller 32. At this time, since the skew roller 32 is rotated by driving of a motor (not shown) or the like, the sheet 33 is fed in the oblique direction K and is brought closer to the side reference guide 34 side according to the rotation of the skew roller 32. At this time, the side edge of the sheet 33 is abutted against the reference surface 35 of the side reference guide 34, thereby correcting the side registration and side skew of the sheet 33. Thereafter, the sheet 33 is transported along the transport direction Y while being guided by the reference surface 35.
[0041]
In such a series of sheet correction operations, the conveyance force F1 by each skew roller 32 is, as shown in FIG. 5, a vector component f1 in the direction along the conveyance direction Y and a direction orthogonal to the conveyance direction Y (side reference guide). 34, the sheet 33 is fed in the oblique direction K by the vector components f1 and f2. When the side edge of the sheet 33 is abutted against the reference surface 35 of the side reference guide 34 by the feeding in the oblique direction K, a reaction force f3 due to the abutment acts on the skew roller 32. The reaction force f3 has a vector component f4 in the rotation axis direction of the skew roller 32, and the vector component f4 causes the outer peripheral portion 37 of the skew roller 32 to be elastic without slipping (sliding) with the paper 33. Deform.
[0042]
As a result, a pressing force when pressing the sheet 33 against the side reference guide 34 is obtained by elastic deformation of the outer peripheral portion 37 of the skew roller 32. Further, when the reaction force f3 due to the abutment increases, slip occurs between the skew roller 32 and the sheet 33 in a state where the skew roller 32 is elastically deformed as described above. Therefore, an excessive pressing force can be released by slipping. As a result, the sheet 33 can always be pressed against the side reference guide 34 with a stable pressing force without being affected by external factors such as the environment such as temperature and humidity, the paper quality, and the presence or absence of toner fixing. Therefore, the sheet correction operation using the skew roller 32 can be stably performed.
[0043]
FIG. 6 is a view showing a modification of the skew roller in the embodiment of the present invention. First, in FIG. 6A, the outer peripheral portion 37 of the skew roller 32 is divided into two in the rotation axis direction, so that two contact portions 37A and 37B are arranged in parallel in the rotation axis direction.
[0044]
In the roller configuration shown in FIG. 6A, the contact portions 37A and 37B are individually elastically deformed by a reaction force caused by abutment against the side reference guide 34. Therefore, a more stable pressing force can be obtained.
[0045]
In FIG. 6B, the outer peripheral portion 37 of the skew roller 32 is made of a material having a high coefficient of friction with the paper 33 (for example, a rubber material such as silicone rubber, urethane rubber, etc.), On the other hand, the contact portion (37) is supported by an elastic support 38 such as a thin disc-shaped plate spring or resin sheet. The elastic support 38 is fitted and fixed to the rotary shaft 36 by a fixing portion 39 made of a retaining ring, an adhesive or the like.
[0046]
In the roller configuration shown in FIG. 6B, the elastic support 38 is elastically deformed by a reaction force caused by abutment against the side reference guide 34, and the sheet 33 is pressed against the side reference guide 34 by the pressing force generated by the elastic deformation. . The elastic support 38 formed of a leaf spring or the like is less susceptible to environmental changes and changes over time than rubber materials. Therefore, it is possible to effectively prevent changes in the pressing force due to environmental changes and changes over time.
[0047]
In FIG. 6C, slits 40 are formed on two orthogonal axes that intersect at the center of the skew roller 32 (90 ° pitch in the circumferential direction of the skew roller 32). These slits 40 are formed so as to cut from the outer peripheral portion 37 of the skew roller 32 in the small-diameter direction of the skew roller 32, whereby the outer peripheral portion 37 of the skew roller 32 is divided into four in the circumferential direction. It has become. In addition, a hole 41 for fitting into the rotary shaft 36 is provided at the center of the skew roller 32.
[0048]
In the roller configuration shown in FIG. 6C, in a state where any one of the outer peripheral portions 37 divided by the slit 40 is in contact with the paper 33, the outer peripheral portion 37 in contact with the paper 33 is the side reference guide. The elastic deformation is started by the reaction force generated by the abutment against 34. Next, before the outer peripheral portion 37 that has started elastic deformation slips between the paper 33, the outer peripheral portion 37 is separated from the paper 33 due to the presence of the slit 40, and is subsequently adjacent to the other (circumferential direction). The outer peripheral portion 37 at the position is in contact with the paper 33. Thereafter, the same operation is repeated. By repeating such an operation, the skew roller 32 applies a pressing force to the paper 33 by elastic deformation of each outer peripheral portion 37 without causing a slip between the skew roller 32 and the paper 33. Therefore, a very stable pressing force can be obtained.
[0049]
FIG. 7 shows an application example of the skew roller in the embodiment of the present invention. FIG. 7A is a side view thereof, and FIG. 7B is a front view thereof. The skew roller 32 shown in FIG. 7 is a combination of the roller configurations shown in FIGS. 6A and 6C. That is, the outer peripheral portion 37 of the skew roller 32 is divided into two in the direction of the rotation axis so that the two contact portions 37A and 37B are arranged in parallel in the direction of the rotation axis. Further, by forming slits 40A and 40B at 90 ° pitches in the circumferential direction of the skew roller 32 with respect to the contact portions 37A and 37B, two contact portions 37A constituting the outer peripheral portion 37 of the skew roller 32 are formed. , 37B are each divided into four in the circumferential direction. Furthermore, the division position (position of the slit 40A) in one contact portion 37A and the division position (position of the slit 40B) in the other contact portion 37B are set with a phase difference of 45 ° from each other.
[0050]
In the roller configuration shown in FIG. 7, the slit 40 </ b> A that divides one contact portion 37 </ b> A faces the sheet 33 in addition to the same effects as the roller configuration shown in FIGS. 6 (A) and (C). In this case, the slit 40B dividing the other contact portion 37B is present at a position shifted by about 45 ° in the circumferential direction from the contact position with the paper 33. As a result, the paper is conveyed and misaligned with at least one of the contact portions 37A and 37B in contact with the paper 33. For this reason, it is possible to further stabilize the pressing force after eliminating the slip between the skew roller 32 and the sheet 33.
[0051]
6A, 6C, 7A, and 7B, two contact portions 37A and 37B are juxtaposed by dividing the outer peripheral portion 37 of the slanting roller 32 having an integral structure. However, a configuration may be adopted in which two skew rollers are attached to the rotary shaft 36 next to each other. Further, the number of contact portions arranged in parallel may be two or more. Further, the slit 40 may be formed at one place or two or more places with respect to one contact portion.
[0052]
In the above-described embodiment, the configuration in which the sheet 33 is shifted toward the side reference guide 34 by the skew roller 32 having a predetermined inclination with respect to the sheet conveyance direction Y is illustrated, but the present invention is not limited thereto. First, two rollers with different outer diameters are mounted on the same rotation shaft, and the paper 33 is moved closer to the side reference guide 34 by utilizing the difference between the outer diameters, or the two rollers are independent rotation shafts. The paper 33 can be applied to the side reference guide 34 side by utilizing the difference in rotational speed between the rollers.
[0053]
Further, in the above-described embodiment, the positional deviation of the paper is corrected before the image forming processing position (secondary transfer position) in the image forming unit. Any device (for example, a document feeder, a post-processing device, etc.) may be used as long as it corrects the positional deviation of the sheet by using a positioning unit and a width-shifting unit such as a skew roller.
[0054]
【The invention's effect】
As described above, according to the paper transport device of the present invention, the paper is always fed with a stable pressing force without being affected by external factors such as the environment such as temperature and humidity, paper quality, and toner fixing. Since the sheet can be pressed against the positioning unit, the sheet correction operation using the width adjusting unit can be stably performed. Therefore, in the image forming apparatus provided with the sheet conveying device, it is possible to always form an image at an appropriate position on the sheet.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an overall configuration of a full-color image forming apparatus to which the present invention is applied.
FIG. 2 is a schematic plan view illustrating a configuration of a main part of the sheet conveying device according to the embodiment of the present invention.
FIG. 3 is a structural comparison view of a skew roller employed in an embodiment of the present invention and a conventional skew roller.
FIG. 4 is a diagram for explaining a difference in outer diameter before and after elastic deformation of a skew roller.
FIG. 5 is a diagram illustrating a state during a paper correction operation of a skew roller.
FIG. 6 is a diagram illustrating a modified example of a skew roller.
FIG. 7 is a diagram illustrating an application example of a skew roller.
[Explanation of symbols]
26: Paper correction unit, 32: Skew roller, 33: Paper, 34: Side reference guide, 35 ... Reference surface, 37 ... Outer peripheral part (contact part), 38 ... Elastic support, 40 ... Slit

Claims (2)

A paper side edge positioning means provided on one side of the paper transport path in parallel with the paper transport direction;
By rotating the paper conveyance path in contact with the paper being conveyed, the paper is brought closer to the paper side edge positioning means and the side edge of the paper is abutted against the paper side edge positioning means, A width adjusting means configured so that a contact portion with respect to the paper can be elastically deformed by a reaction force caused by abutting against the paper side edge positioning means ;
The width adjusting means is configured using a skew roller having an outer peripheral portion as the contact portion, and a plurality of the contact portions are arranged in parallel in the rotation axis direction of the skew roller, and By forming a plurality of slits that cut in the small diameter direction of the skew roller at each of the contact portions arranged in parallel, each of the contact portions is divided into a plurality in the circumferential direction of the skew roller, and the parallel arrangement Among the plurality of contact portions, the phase of the division position by the plurality of slits formed in one contact portion and the division position by the plurality of slits formed in the other contact portion are expressed in the circumferential direction of the skew roller. The sheet conveying apparatus is configured to be shifted from each other . The sheet conveying apparatus according to claim 1.
An image forming apparatus.

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