JP5358500B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a printer, a copier, a facsimile, or a complex machine of these.

  Conventionally, as an apparatus for printing (forming) an image on a sheet as a transfer material, an image forming apparatus such as a printer, a copier, or a complex machine of these is known. Generally, in an image forming apparatus, a sheet detection sensor for detecting a sheet, a registration roller pair, and a sheet as a registration roller pair are arranged upstream of the sheet conveyance direction in an image forming unit that forms an image on the sheet. A pair of conveying rollers to be sent out is disposed.

  The registration roller pair is a pair of rollers for correcting skew of the paper (oblique feeding) and adjusting timing with the toner image before sending the paper to the image forming unit. The registration roller pair carries out the correction and timing adjustment based on the detection signal information from the paper detection sensor, and conveys the paper toward the transfer nip.

In a stopped state, the registration roller pair temporarily contacts the leading edge of the sheet to form a predetermined curve on the sheet, and then rotates to send the sheet to the image forming unit.
Specifically, the sheet that is in contact with the stopped registration roller pair is sent to the registration roller pair side by a predetermined amount by the conveying roller pair based on detection signal information from the sheet detection sensor. As a result, the sheet is curved in a state where the leading edge is pressed toward the registration nip formed in the registration roller pair. The magnitude of the curve formed on the paper is adjusted by the amount of paper delivered by the pair of transport rollers.

  However, it is difficult to adjust the shape of the curve formed on the paper depending on the amount of paper fed by the pair of transport rollers. For this reason, depending on the curved shape formed on the paper, the protruding curved portion formed on the paper comes into contact with the guide constituting the conveyance path. As a result, abnormal noise as an impact sound may occur.

In addition, when the paper on which the curve is formed is sent out toward the image forming unit by the pair of registration rollers, the curve formed on the paper is eliminated and returns to a straight line. When the curve formed on the sheet returns to a straight line, abnormal noise may occur.
In particular, when the conveyance path for conveying a sheet is curved in a complicated manner, a plurality of complicated S-order curves may be formed on the sheet. Abnormal noise may occur. As a result, there is a problem in that abnormal noise generated when the paper is conveyed may cause discomfort to surrounding users.

As an image forming apparatus that can reduce abnormal noise caused by a curve formed on a sheet, a movable guide that moves the curve formed on the sheet in a direction that intersects the conveyance direction, and a movable guide that is disposed opposite the movable guide. An image forming apparatus including a fixed guide has been proposed (see, for example, Patent Document 1).
In the image forming apparatus described in Patent Document 1, the sheet contacts the movable guide before the curve is formed. When the curve is formed on the sheet, the movable guide moves. As a result, the image forming apparatus described in Patent Document 1 can reduce the impact sound generated when the sheet collides with the guide.

JP 2009-40539 A

  However, the image forming apparatus described in Patent Document 1 is provided with a movable guide that moves so as to absorb an impact when a sheet collides, and the configuration is complicated. Moreover, since the configuration is complicated, the cost increases.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes a pair of registration rollers and can reduce abnormal noise caused by curving a sheet T in skew (oblique feeding) correction with a simple configuration. To do.

  The present invention includes an image forming unit that forms an image on a sheet-shaped transfer material, a main storage unit that stores the transfer material, and a sub-accommodation unit that stores the transfer material and is different from the main storage unit. A main conveyance path that conveys the transfer material accommodated in the main accommodation section toward the image forming section, and a registration roller pair that is disposed in the main conveyance path and forms a registration nip, A pair of registration rollers that feeds a transfer material toward the image forming unit, and a pair of conveyance rollers that are disposed on the main housing unit side of the registration roller pair in the main conveyance path and form a conveyance nip, A conveying roller pair for curving the material to be transferred by bringing a leading end of the material into contact with the registration roller pair, and a sub-conveying path for conveying the material to be transferred stored in the sub-accommodating portion toward the resist roller pair. The resist In a pair of rollers, a sub-conveying path that merges with the main conveying path on the upstream side in the conveying direction of the transfer material, and the main conveying path and the sub-conveying path are arranged so as to partition, and is conveyed in the sub-conveying path A plate-shaped guide member that guides the material to be transferred toward the pair of registration rollers, and the guide member is disposed on the main conveyance path side to face the guide member, and is conveyed in the main conveyance path. A guide member for guiding the transferred material toward the pair of registration rollers, and a guide member on the downstream side in the transport direction of the guide member, and connecting the registration nip and the transport nip. The present invention relates to an image forming apparatus including a protruding portion protruding toward the main conveyance path side guide member with respect to a nip connection plane.

  Further, it is preferable that the protruding portion guides the transferred material such that the transferred material forms a curve protruding toward the main conveyance path side guide member.

  The registration nip plane including the registration nip is preferably formed on the main conveyance path side guide member side with respect to the nip connection plane on the upstream side in the conveyance direction of the registration roller pair.

  The transport nip plane including the transport nip is preferably formed on the main transport path side guide member side with respect to the nip connection plane on the downstream side in the transport direction of the transport roller pair.

  Further, it is preferable that the protruding portion is disposed on the resist nip side from a position where the distance from the resist nip and the transport nip is equal on the nip connection plane.

  The registration roller pair includes a registration driving roller and a registration counter roller disposed opposite to the registration driving roller in proximity to or in contact with the registration driving roller. It is preferable to have a conveyance drive roller disposed on the opposite side of the drive roller and a conveyance counter roller disposed close to or in contact with the conveyance drive roller.

  The resist driving roller is formed of a material that does not substantially deform at a portion where the resist nip is formed, and the resist-opposing roller is formed of a material having flexibility and elasticity at a portion where the resist nip is formed. The transport driving roller is formed of a material that does not substantially deform in a portion that forms the transport nip, and the transport counter roller is formed of a material that has flexibility and elasticity in a portion that forms the transport nip. It is preferred that

  According to the present invention, it is possible to provide an image forming apparatus that includes a pair of registration rollers and that can reduce abnormal noise caused by curving the paper T in skew (oblique feeding) correction with a simple configuration. it can.

FIG. 2 is a front view for explaining the arrangement of each component in the printer 1 of the present embodiment. 6 is a schematic diagram illustrating a configuration relating to a first conveyance path L1 between a paper feed cassette 52 and a registration roller pair 80 in the printer 1 of the present embodiment. FIG. FIG. 6 is a diagram illustrating a state in which the leading edge of the paper T sent to the first transport roller pair is in contact with a protruding portion 852 in the printer 1 of the present embodiment. FIG. 6 is a diagram illustrating a state in which the leading edge of a sheet T that is in contact with a protruding portion 852 is guided to the first conveyance path side guide member 861 side in the printer 1 of the present embodiment. In the printer 1 of the present embodiment, the state in which the sheet T is conveyed toward the registration roller pair 80 in a state where the curve protruding to the first conveyance path side guide member 861 is formed on the sheet T is described. . FIG. 6 is a diagram illustrating a state in which the sheet T abuts against a registration roller pair 80 in a state where a curve protruding toward the first conveyance path side guide member 861 is formed on the sheet T in the printer 1 of the present embodiment. In the printer 1 of the present embodiment, the sheet T is fed in a state where the sheet T is curved so as to project toward the first conveyance path side guide member 861 by being sent out from the state illustrated in FIG. 3D to the first conveyance roller pair 82. It is a figure which shows a mode that it curves so that the 1st conveyance path side guide member 861 may be met.

Hereinafter, embodiments of an image forming apparatus of the present invention will be described with reference to the drawings.
The overall structure of a printer 1 as an image forming apparatus according to the present embodiment will be described with reference to FIG. FIG. 1 is a front view for explaining the arrangement of components in the printer 1 of the present embodiment.

As shown in FIG. 1, a printer 1 as an image forming apparatus includes an apparatus main body M and an image forming unit GK that forms a predetermined toner image on a sheet T as a sheet-like transfer material based on predetermined image information. And a paper supply / discharge unit KH that supplies the paper T to the image forming unit GK and discharges the paper T on which the toner image is formed.
The outer shape of the apparatus main body M is configured by a case body BD as a casing.

  As shown in FIG. 1, the image forming unit GK includes photosensitive drums 2a, 2b, 2c, and 2d as image carriers (photosensitive members), charging units 10a, 10b, 10c, and 10d, and a laser as an exposure unit. Scanner units 4a, 4b, 4c, 4d, developing devices 16a, 16b, 16c, 16d, toner cartridges 5a, 5b, 5c, 5d, toner supply units 6a, 6b, 6c, 6d, drum cleaning unit 11a, 11b, 11c, 11d, static eliminators 12a, 12b, 12c, 12d, intermediate transfer belt 7, primary transfer rollers 37a, 37b, 37c, 37d, secondary transfer roller 8, counter roller 18, fixing Part 9.

  As shown in FIG. 1, the paper feed / discharge unit KH includes a paper feed cassette 52, a manual paper feed unit 64, a conveyance path L for paper T, a registration roller pair 80, a plurality of rollers or roller pairs, A paper unit 50. As will be described later, the transport path L includes a first transport path L1, a second transport path L2, a third transport path L3, a manual transport path La as a sub transport path, and a return. It is an aggregate with the conveyance path Lb.

Hereinafter, each configuration of the image forming unit GK and the paper supply / discharge unit KH will be described in detail.
First, the image forming unit GK will be described.
In the image forming unit GK, charging by the charging units 10a, 10b, 10c, and 10d in order from the upstream side to the downstream side in order along the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d, the laser scanner unit 4a, 4b, 4c, 4d exposure, development devices 16a, 16b, 16c, 16d development, intermediate transfer belt 7 and primary transfer rollers 37a, 37b, 37c, 37d primary transfer, static eliminators 12a, 12b, 12c, 12d Is eliminated, and cleaning is performed by the drum cleaning units 11a, 11b, 11c, and 11d.
Further, in the image forming unit GK, secondary transfer by the intermediate transfer belt 7, the secondary transfer roller 8 and the counter roller 18, and fixing by the fixing unit 9 are performed.

  Each of the photosensitive drums 2a, 2b, 2c, and 2d is formed of a cylindrical member and functions as a photosensitive member or an image carrier. Each of the photosensitive drums 2 a, 2 b, 2 c, and 2 d is disposed so as to be rotatable in the direction of an arrow about an axis that extends in a direction orthogonal to the traveling direction of the intermediate transfer belt 7. An electrostatic latent image can be formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d.

  Each of the charging units 10a, 10b, 10c, and 10d is disposed to face the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the charging units 10a, 10b, 10c, and 10d uniformly charges the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d negatively (minus polarity) or positively (plus polarity).

  The laser scanner units 4a, 4b, 4c, and 4d function as exposure units, and are spaced apart from the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the laser scanner units 4a, 4b, 4c, and 4d includes a laser light source (not shown), a polygon mirror, a polygon mirror driving motor, and the like.

  Each of the laser scanner units 4a, 4b, 4c, and 4d scans and exposes the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d based on image information input from an external device such as a PC (personal computer). The scanning exposure is performed by each of the laser scanner units 4a, 4b, 4c, and 4d, thereby removing the charges on the exposed portions of the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Thereby, electrostatic latent images are formed on the respective surfaces of the photosensitive drums 2a, 2b, 2c, and 2d.

  The developing devices 16a, 16b, 16c, and 16d are provided corresponding to the photosensitive drums 2a, 2b, 2c, and 2d, respectively, and are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d. Each of the developing devices 16a, 16b, 16c, and 16d attaches the toner of each color to the electrostatic latent image formed on the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d, and converts the color toner image into the photosensitive drum. 2a, 2b, 2c and 2d are formed on the respective surfaces. Each of the developing devices 16a, 16b, 16c, and 16d corresponds to four colors of yellow, cyan, magenta, and black. Each of the developing devices 16a, 16b, 16c, and 16d includes a developing roller disposed opposite to the surface of the photosensitive drums 2a, 2b, 2c, and 2d, a stirring roller for stirring the toner, and the like.

  Each of the toner cartridges 5a, 5b, 5c, and 5d is provided corresponding to each of the developing devices 16a, 16b, 16c, and 16d, and each color toner supplied to each of the developing devices 16a, 16b, 16c, and 16d. To accommodate. Each of the toner cartridges 5a, 5b, 5c, and 5d accommodates yellow toner, cyan toner, magenta toner, and black toner.

  The toner supply units 6a, 6b, 6c, and 6d are provided corresponding to the toner cartridges 5a, 5b, 5c, and 5d and the developing devices 16a, 16b, 16c, and 16d, respectively. The toners of the respective colors accommodated in 5d are supplied to the developing devices 16a, 16b, 16c, and 16d, respectively. Each of the toner supply units 6a, 6b, 6c, and 6d and each of the developing devices 16a, 16b, 16c, and 16d are connected by a toner supply path (not shown).

  To the intermediate transfer belt 7, the toner images of the respective colors formed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially primary-transferred. The intermediate transfer belt 7 is stretched around a driven roller 35, a counter roller 18 including a driving roller, a tension roller 36, and the like. Since the tension roller 36 biases the intermediate transfer belt 7 from the inside to the outside, a predetermined tension is applied to the intermediate transfer belt 7.

  Primary transfer rollers 37a, 37b, 37c, and 37d are arranged to face each other on the side opposite to the photosensitive drums 2a, 2b, 2c, and 2d with the intermediate transfer belt 7 interposed therebetween.

  A predetermined portion of the intermediate transfer belt 7 is sandwiched between the primary transfer rollers 37a, 37b, 37c, and 37d and the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The predetermined portion thus sandwiched is pressed against the surface of each of the photosensitive drums 2a, 2b, 2c, and 2d. Primary transfer nips N1a, N1b, N1c, and N1d are formed between the photosensitive drums 2a, 2b, 2c, and 2d and the primary transfer rollers 37a, 37b, 37c, and 37d, respectively. In each of the primary transfer nips N1a, N1b, N1c, and N1d, the toner images of the respective colors developed on the photosensitive drums 2a, 2b, 2c, and 2d are sequentially primary-transferred onto the intermediate transfer belt 7, respectively. As a result, a full-color toner image is formed on the intermediate transfer belt 7.

  To the primary transfer rollers 37a, 37b, 37c, and 37d, toner images of the respective colors formed on the photosensitive drums 2a, 2b, 2c, and 2d are respectively transferred to the intermediate transfer belt 7 by a primary transfer bias applying unit (not shown). A primary transfer bias for transferring the toner image is applied.

  The static eliminators 12a, 12b, 12c, and 12d are arranged to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. The static eliminators 12a, 12b, 12c, and 12d respectively irradiate the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d to irradiate light, and the photosensitive drums 2a, 2b, and 2c after the primary transfer is performed. 2d, each surface is neutralized (charge is removed).

  The drum cleaning units 11a, 11b, 11c, and 11d are disposed to face the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, respectively. Each of the drum cleaning units 11a, 11b, 11c, and 11d removes toner and adhering matter remaining on the surfaces of the photosensitive drums 2a, 2b, 2c, and 2d, and conveys the removed toner to a predetermined recovery mechanism. And collect it.

  The secondary transfer roller 8 secondarily transfers the full-color toner image primarily transferred to the intermediate transfer belt 7 onto the paper T. A secondary transfer bias for transferring the full color toner image formed on the intermediate transfer belt 7 to the paper T is applied to the secondary transfer roller 8 by a secondary transfer bias applying unit (not shown).

  The secondary transfer roller 8 contacts or separates from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is configured to be movable between a contact position where the secondary transfer roller 8 is in contact with the intermediate transfer belt 7 and a spaced position where the secondary transfer roller 8 is separated from the intermediate transfer belt 7. Specifically, the secondary transfer roller 8 is disposed at a contact position when the full-color toner image primarily transferred onto the surface of the intermediate transfer belt 7 is secondarily transferred to the paper T, and in other cases. It is arranged at a separated position.

  A counter roller 18 is disposed on the opposite side of the intermediate transfer belt 7 from the secondary transfer roller 8. A predetermined portion of the intermediate transfer belt 7 is sandwiched between the secondary transfer roller 8 and the opposing roller 18. Then, the paper T is pressed against the outer surface of the intermediate transfer belt 7 (the surface on which the toner image is primarily transferred). A secondary transfer nip N <b> 2 is formed between the intermediate transfer belt 7 and the secondary transfer roller 8. In the secondary transfer nip N2, the full-color toner image primarily transferred to the intermediate transfer belt 7 is secondarily transferred to the paper T.

  The fixing unit 9 melts and presses the toner of each color constituting the toner image secondarily transferred onto the paper T and fixes the toner on the paper T. The fixing unit 9 includes a heating rotator 9a heated by a heater and a pressure rotator 9b pressed against the heating rotator 9a. The heating rotator 9a and the pressure rotator 9b sandwich and pressurize the paper T onto which the toner image has been secondarily transferred, and convey the paper T. When the paper T is conveyed while being sandwiched between the heating rotator 9a and the pressure rotator 9b, the toner transferred to the paper T is fixed on the paper T by being melted and pressurized. Is done.

Next, the paper supply / discharge unit KH will be described.
As shown in FIG. 1, a sheet feeding cassette 52 serving as a main accommodating portion that accommodates the paper T is disposed below the apparatus main body M. The paper feed cassette 52 is configured to be pulled out from the housing of the apparatus main body M in the horizontal direction. In the paper feed cassette 52, a placement plate 60 on which the paper T is placed is disposed. In the paper feed cassette 52, the paper T is stored in a state of being stacked on the placement plate 60. The paper T placed on the placement plate 60 is sent out to the transport path L by the cassette paper feed unit 51 arranged at the paper feed side end of the paper feed cassette 52 (the right end in FIG. 1). The cassette paper feeding unit 51 includes a forward feed roller 61 for taking out the paper T on the placement plate 60 and a paper feed roller pair 81 for feeding the paper T one by one to the transport path L. Is provided.

  On the left side surface (left side in FIG. 1) of the apparatus main body M, a manual paper feed unit 64 as a sub-accommodating unit that accommodates the paper T is provided. The manual paper feed unit 64 is a paper feed unit different from the paper feed cassette 52. The manual paper feed unit 64 is provided mainly for supplying the apparatus main body M with a paper T of a size and type different from the paper T set in the paper feed cassette 52. The manual paper feed unit 64 includes a manual feed tray 65 that forms a part of the left side surface of the apparatus main body M in the closed state, and a paper feed roller 66. The lower end of the manual feed tray 65 is attached to the vicinity of the paper feed roller 66 so as to be rotatable (openable and closable). The paper T is placed on the open manual feed tray 65. The paper feed roller 66 feeds the paper T placed on the open manual feed tray 65 to the manual feed path La.

  The conveyance path L for conveying the paper T includes a first conveyance path L1 from the cassette paper feeding unit 51 to the secondary transfer nip N2, a second conveyance path L2 from the secondary transfer nip N2 to the fixing unit 9, and a fixing unit. 9 to the paper discharge unit 50, the manual feed path La for joining the paper supplied from the paper feed unit 64 to the first transport path L1, and the third transport path L3 from the downstream side to the upstream side. And a return transport path Lb that reverses the front and back of the sheet to be transported to the first transport path L1.

  The first transport path L1 transports the paper T stored in the paper feed cassette 52 toward the image forming unit GK. The manual feed path La transports the paper T accommodated in the manual paper feed unit 64 toward a registration roller pair 80 described later.

Moreover, the 1st junction part P1 and the 2nd junction part P2 are provided in the middle of the 1st conveyance path L1. A first branch portion Q1 is provided in the middle of the third transport path L3.
The first joining part P1 is a joining part where the manual feed path La joins the first transport path L1. The second junction P2 is a junction where the return conveyance path Lb merges with the first conveyance path L1.
The first branch portion Q1 is a branch portion where the return transport path Lb branches from the third transport path L3.

  In the middle of the first conveyance path L1 (specifically, between the second joining portion P2 and the secondary transfer roller 8), a sheet detection sensor (not shown) for detecting the sheet T, A registration roller pair 80 is arranged to synchronize with skew (oblique sheet feeding) correction and toner image formation in the image forming unit GK. The paper detection sensor is disposed immediately before the registration roller pair 80 in the transport direction of the paper T (upstream in the transport direction). The registration roller pair 80 conveys the paper T by performing the above-described correction and timing adjustment based on detection signal information from the paper detection sensor.

  A first conveyance roller pair 82 as a conveyance roller pair is disposed between the first merge portion P1 and the second merge portion P2 in the first conveyance path L1. The first transport roller pair 82 is disposed on the downstream side of the paper feed roller pair 81, sandwiches the paper T transported from the paper feed roller pair 81, and transports the paper T to the registration roller pair 80.

  The return conveyance path Lb is a conveyance path that is provided to make the opposite surface (unprinted surface) opposite to the already printed surface to the intermediate transfer belt 7 when performing duplex printing on the paper T. According to the return transport path Lb, the paper T transported from the first branching section Q1 to the paper discharge section 50 is turned upside down and returned to the first transport path L1 and arranged upstream of the secondary transfer roller 8. It can be conveyed to the upstream side of the pair of registration rollers 80. A predetermined toner image is transferred onto the unprinted surface in the secondary transfer nip N2 on the paper T that is reversed upside down by the return conveyance path Lb.

  A rectifying member 58 is provided in the first branch portion Q1. The rectifying member 58 rectifies the transport direction of the paper T that is carried out of the fixing unit 9 and transports the third transport path L3 from the upstream side toward the downstream side in a direction toward the paper discharge unit 50 and the paper discharge unit 50. The conveyance direction of the paper T that is conveyed from the downstream side toward the upstream side of the third conveyance path L3 is rectified in a direction toward the return conveyance path Lb.

  A paper discharge unit 50 is formed at the end of the third transport path L3. The paper discharge unit 50 is disposed on the upper side of the apparatus main body M. The paper discharge unit 50 opens toward the left side of the apparatus main body M (left side in FIG. 1). The paper discharge unit 50 discharges the paper T to the outside of the apparatus main body M. The paper discharge unit 50 includes a discharge roller pair 53. According to the discharge roller pair 53, the paper T conveyed from the upstream side to the downstream side in the third conveyance path L3 is discharged to the outside of the apparatus main body M, and the conveyance direction of the paper T is reversed in the paper discharge unit 50. Thus, the paper T can be transported toward the upstream side of the third transport path L3.

On the opening side of the paper discharge unit 50, a paper discharge stacking unit M1 is formed. The paper discharge stacking unit M1 is formed on the upper surface (outer surface) of the apparatus main body M. The paper discharge stacking unit M1 is a part formed by the upper surface of the apparatus main body M being depressed downward. The bottom surface of the paper discharge stacking unit M1 constitutes a part of the top surface of the apparatus main body M. In the paper discharge stacking unit M1, sheets T formed with a predetermined toner image and discharged from the paper discharge unit 50 are stacked and stacked.
A paper detection sensor is disposed at a predetermined position on each conveyance path.

  Hereinafter, with reference to the drawings, a configuration related to a characteristic part in the printer 1 of the present embodiment will be described. FIG. 2 is a schematic diagram showing a configuration relating to the first conveyance path L1 between the paper feed cassette 52 and the registration roller pair 80 in the printer 1 of the present embodiment.

  As shown in FIG. 2, the first conveyance path L1 between the paper feed cassette 52 and the registration roller pair 80 is directed from the paper feed cassette 52 to the registration roller pair 80 (from the upstream side to the downstream side). A forward feed roller 61, a paper feed roller pair 81, a first transport roller pair 82, and a registration roller pair 80 are disposed.

  The paper T stored in the paper feed cassette 52 is sequentially sent out by the forward feed roller 61, the paper feed roller pair 81, and the first transport roller pair 82, and is transported through the first transport path L1 toward the registration roller pair 80. . The first transport path L1 extends upward in the overall view.

  Also, as shown in FIG. 1, the manual feed path La between the manual paper feed unit 64 and the registration roller pair 80 is directed from the manual paper feed unit 64 toward the registration roller pair 80 (from the upstream side to the downstream side). On the other hand, a paper feed roller 66, a plurality of conveyance roller pairs, and a registration roller pair 80 are arranged.

  The paper T stored in the manual paper feed unit 64 is sequentially sent out by a paper feed roller 66 and a plurality of transport roller pairs, and is transported through the manual transport path La toward the registration roller pair 80. The manual feed path La feeds with the image forming unit GK from the one side (the left side of the case body BD in FIG. 1) in the horizontal direction (X direction) to the other side (the first transport path L1 side) of the case body BD. It is formed so as to cross through the cassette 52. The end of the manual feed path La on the first transport path L1 side is curved upward and joins the upstream side of the registration roller pair 80 in the transport direction.

Further, as described above, the paper detection sensor (not shown) is disposed immediately before the registration roller pair 80 in the transport direction of the paper T (upstream in the transport direction). In the present embodiment, the paper detection sensor is disposed immediately before the registration roller pair 80 in the first conveyance path L1 and immediately before the registration roller pair 80 in the manual conveyance path La.
The paper detection sensor can detect the presence or absence of the paper T that is transported immediately before the registration roller pair 80 by using the reflected light.

  As shown in FIG. 2, a first junction P <b> 1 is formed in the vicinity of the upstream side in the conveyance direction of the paper T in the registration roller pair 80. The first junction P1 is a junction where the first conveyance path L1 and the manual conveyance path La are merged. The manual conveyance path La joins the first conveyance path L1 in the horizontal direction at the first merging portion P1 on the upstream side of the registration roller pair 80 in the conveyance direction of the paper T.

  Immediately before the registration roller pair 80 in the first junction P1, a first introduction guide for guiding the paper T conveyed on the first conveyance path L1 and the manual conveyance path La to a registration nip N80 (described later) of the registration roller pair 80. A member 806 and a second introduction guide member 807 are disposed.

  The first introduction guide member 806 and the second introduction guide member 807 are plate-like members. The first introduction guide member 806 and the second introduction guide member 807 are disposed so as to be inclined so that the interval becomes narrower toward the registration nip N80. The first introduction guide member 806 and the second introduction guide member 807 are arranged so that the sheet T conveyed on the first conveyance path L1 and the manual conveyance path La immediately before the registration roller pair 80 is a registration nip N80 (described later) of the registration roller pair 80. ).

  A partition guide member 851 as a guide member disposed so as to partition the first transport path L1 and the manual transport path La is disposed between the first transport path L1 and the manual transport path La. The partition guide member 851 guides the sheet T conveyed on the manual conveyance path La toward the registration roller pair 80.

  The partition guide member 851 is a plate-like member formed so as to extend from obliquely downward toward the first merging portion P1. Specifically, the partition guide member 851 extends while curving so as to gradually approach the first conveyance path L1 side from the manual conveyance path La side as it goes from below to above.

  A first transport path side guide member 861 that guides the paper T transported in the first transport path L1 toward the registration roller pair 80 is disposed in the first transport path L1. The first transport path side guide member 861 is disposed on the first transport path L1 side with respect to the partition guide member 851. Further, the first conveyance path side guide member 861 is disposed to face the partition guide member 851. The first conveyance path side guide member 861 is inclined and extended in a direction approaching a registration nip N80 (described later) formed in the registration roller pair 80 toward the registration roller pair 80.

  In the manual feed path La, a manual feed path side guide member 871 for guiding the paper T conveyed in the manual feed path La toward the registration roller pair 80 is disposed. The manual feed path side guide member 871 is disposed on the manual feed path La side with respect to the partition guide member 851. The manual feed path side guide member 871 extends while curving in a direction approaching a registration nip N80 (described later) formed in the registration roller pair 80 toward the registration roller pair 80. Further, the manual feed path side guide member 871 is disposed to face the partition guide member 851.

A protruding portion 852 is formed on the leading end side of the partition guide member 851 on the downstream side in the transport direction. The protrusion 852 is formed so as to protrude toward the first conveyance path side guide member 861 with respect to a nip connection plane 880 (described later) connecting a registration nip N80 (described later) and a conveyance nip N82 (described later).
Details of the protrusion 852 will be described later.

Next, the forward feed roller 61, the paper feed roller pair 81, the first transport roller pair 82, and the registration roller pair 80 arranged in the first transport path L1 will be described.
The front feed roller 61 is disposed at the end of the paper feed cassette 52 on the paper feed side (the right end in FIG. 1), and constitutes the cassette paper feed unit 51 together with the paper feed roller pair 81. According to the forward feed roller 61, the paper T placed on the placement plate 60 in the lifted state is taken out from the paper feed cassette 52 and sent out to the transport path L (first transport path L <b> 1).

  The roller shaft of the forward feed roller 61 is connected to a forward feed roller driving unit (not shown) that rotationally drives the forward feed roller 61. The forward feed roller 61 is rotationally driven at a predetermined speed by the forward feed roller driving unit. Accordingly, the forward feed roller 61 can convey the paper T stored in the paper feed cassette 52 toward the paper feed roller pair 81.

  The paper feed roller pair 81 is disposed on the downstream side of the forward feed roller 61. The paper feed roller pair 81 includes a paper feed drive roller 811 and a separation roller 812. The paper feed drive roller 811 is disposed above the separation roller 812.

  A paper feed roller drive unit (not shown) that rotates the paper feed drive roller 811 is connected to the roller shaft of the paper feed drive roller 811. The paper feed drive roller 811 is driven to rotate at a predetermined speed by the paper feed roller drive unit, and the separation roller 812 is rotated following the rotation of the paper feed drive roller 811. As a result, the paper feed roller pair 81 can sandwich and transport the paper T fed by the forward feed roller 61.

  The separation roller 812 is provided to separate the sheets T fed by the sheet feed driving roller 811 one by one. In other words, the separation roller 812 is provided to prevent double feeding of the paper T (a plurality of papers T are sent out in a state where they are overlapped). The surface (circumferential surface) of the separation roller 812 is formed of a material having a high friction coefficient such as rubber. According to the separation roller 812, the separation roller 812 uses the height of the friction coefficient to come into contact with the paper T from the side opposite to the paper feed driving roller 811 and when the paper T is likely to be double-fed, the separation roller 812 It is possible to prevent the paper T in contact with 812 from being sent out.

  The first transport roller pair 82 is disposed on the downstream side of the paper feed roller pair 81 and on the upstream side of a registration roller pair 80 described later in the first transport path L1. In other words, the first conveyance roller pair 82 is disposed closer to the paper feed cassette 52 than the registration roller pair 80 (described later) in the first conveyance path L1. The first conveying roller pair 82 causes the leading edge of the paper T to abut a registration roller pair 80 described later to bend the paper T.

  The first conveyance roller pair 82 includes a conveyance driving roller 821 and a conveyance counter roller 822. The conveyance driving roller 821 and the conveyance counter roller 822 are arranged side by side in a substantially horizontal direction. The conveyance drive roller 821 is disposed on the opposite side (the right side in FIG. 2) to the manual conveyance path La with respect to a nip connection plane 880 described later. The conveyance counter roller 822 is disposed on the manual conveyance path La side (left side in FIG. 2) with respect to the nip connection plane 880. The conveyance facing roller 822 is disposed in close proximity to or in contact with the conveyance driving roller 821.

  The first conveyance roller pair 82 includes a conveyance driving roller 821 and a conveyance counter roller 822 to form a conveyance nip N82. The first transport roller pair 82 sandwiches the paper T transported by the paper feed roller pair 81, passes through the transport nip N 82, and transports it toward the registration roller pair 80. A conveyance nip plane 825 including the conveyance nip N82 is formed on the first conveyance path side guide member 861 side with respect to a nip connection plane 880 described later on the downstream side of the first conveyance roller pair 82.

The conveyance drive roller 821 is formed of a material that does not substantially deform at a portion where the conveyance nip N82 is formed. The conveyance facing roller 822 is formed of a material having flexibility and elasticity at a portion where the conveyance nip N82 is formed.
Specifically, the transport driving roller 821 is formed of a resin material having a high surface layer. The transport facing roller 822 is formed of a resin material whose surface layer has a hardness lower than that of the transport driving roller 821.

  Examples of materials that can be used as the transport driving roller 821 and the transport counter roller 822 include, for example, synthetic resins such as fluororesin, various rubbers such as urethane rubber, chloroprene rubber, and silicon rubber, foamed urethane resin, and foamed silicon resin. Examples of these materials include foamed synthetic resins and the like. Among these materials, one having high hardness and one having low hardness can be appropriately selected and used.

  A conveyance roller driving unit (not shown) for rotating the conveyance driving roller 821 is connected to the roller shaft 821A of the conveyance driving roller 821. The conveyance roller driving unit drives the conveyance driving roller 821 to rotate at a predetermined speed, and the conveyance counter roller 822 is rotated following the rotation of the conveyance driving roller 821. Accordingly, the first transport roller pair 82 can sandwich the paper T fed by the paper feed roller pair 81 and transport the paper T toward the registration roller pair 80.

  The registration roller pair 80 is disposed on the downstream side of the first conveyance roller pair 82. The registration roller pair 80 includes a registration driving roller 801 and a registration counter roller 802. The registration drive roller 801 is disposed on the manual feed path side guide member 871 side (left side in FIG. 2) with respect to a nip connection plane 880 described later. The registration driving roller 801 is disposed on the opposite side of the conveyance driving roller 821 with respect to the nip connection plane 880.

  The resist facing roller 802 is disposed on the first transport path side guide member 861 side (right side in FIG. 2) with respect to a nip connection plane 880 described later. The resist facing roller 802 is disposed so as to be close to or in contact with the resist driving roller 801. The resist facing roller 802 is disposed on the opposite side of the conveyance facing roller 822 with respect to the nip connection plane 880.

The registration roller pair 80 forms a registration nip N80 by a registration driving roller 801 and a registration counter roller 802. The registration roller pair 80 sandwiches the paper T conveyed by the first conveyance roller pair 82, passes through the registration nip N80, and conveys it to the image forming unit GK.
A plane connecting the registration nip N80 and the conveyance nip N82 is referred to as a nip connection plane 880. A registration nip plane 805 including the registration nip N80 is formed on the first conveyance path side guide member 861 side with respect to the nip connection plane 880 on the upstream side of the registration roller pair 80.

  Similar to the conveyance drive roller 821, the registration drive roller 801 is formed of a resin material having a high hardness on the surface layer. The resist facing roller 802 is formed of a resin material whose surface layer has a lower hardness than the resist driving roller 801. The materials that can be employed as the registration driving roller 801 and the registration counter roller 802 are the same as those of the conveyance driving roller 821 and the conveyance counter roller 822 described above.

  The registration driving roller 801 and the registration counter roller 802 are arranged side by side in a direction inclined from the horizontal direction. Specifically, the registration driving roller 801 is disposed at a position on the lower side in the vertical direction Z with respect to the registration facing roller 802. As a result, the line connecting the center of the rotation shaft of the registration driving roller 801 and the center of the rotation shaft of the registration counter roller 802 is inclined so that the manual feed path La side is lowered.

  A registration driving unit (not shown) for rotating the registration driving roller 801 is connected to the roller shaft 801A of the registration driving roller 801. The registration driving unit rotates the registration driving roller 801 at a predetermined speed, and the registration opposing roller 802 is rotated by the rotation of the registration driving roller 801. Thus, the registration roller pair 80 can synchronize with the skew correction of the paper T sent out by the first conveyance roller pair 82 and the formation of the toner image in the image forming unit GK.

Next, the detail of the protrusion part 852 in the partition guide member 851 is demonstrated.
The protruding portion 852 is formed by using a partition guide member 851 that partitions the first transport path L1 and the manual transport path La. The protruding portion 852 is formed on the distal end side of the partition guide member 851 on the downstream side in the transport direction. The protruding portion 852 is formed so as to protrude toward the first conveyance path side guide member 861 with respect to the nip connection plane 880 connecting the registration nip N80 and the conveyance nip N82.

  The protrusion 852 is disposed in the vicinity of the registration nip N80. Specifically, the protrusion 852 is disposed on the side of the resist nip N80 from the position where the distance from the resist nip N80 and the conveyance nip N82 is equal on the nip connection plane 880.

  The protruding portion 852 guides the paper T so that the paper T forms a curve that protrudes toward the first conveyance path side guide member 861. Specifically, the protrusion 852 triggers the leading edge of the sheet T conveyed on the first conveyance path L1 to be guided toward the first conveyance path side guide member 861 by the contact of the sheet T.

  Further, the protruding portion 852 regulates the sheet T formed with the curve protruding toward the first conveyance path side guide member 861 so that the curve protruding toward the side opposite to the first conveyance path side guide member 861 is not formed. . As a result, the sheet T on which the curve projecting toward the first conveyance path side guide member 861 side is regulated by the projecting portion 852 even if it has a behavior that flutters in the horizontal direction, for example. The curve protruding toward the first conveyance path side guide member 861 is maintained.

  Specifically, the protruding portion 852 protrudes such that the surface on the first conveyance path L1 side of the partition guide member 851 intersects the nip connection plane 880. Specifically, the protruding portion 852 is loose so as to straddle the nip connection plane 880 from the conveyance facing roller 822 side to the conveyance driving roller 821 side in the first conveyance roller pair 82 in the middle of the partition guide member 851 from the lower side to the upper side. It protrudes in a state where it is inclined.

  Thus, the sheet T conveyed by the first conveying roller pair 82 is guided to the first conveying path side guide member 861 side and conveyed toward the registration roller pair 80 by abutting against the protruding portion 852.

In the portion where the protrusion 852 is formed, the width of the first transport path L1 (the length in the direction perpendicular to the paper transport direction) is the width of the manual transport path La (the length in the direction perpendicular to the paper transport direction). ).
Specifically, the length in the transport width direction orthogonal to the transport direction of the paper T to the surfaces of the partition guide member 851 and the first transport path side guide member 861 is the surface of the partition guide member 851 and the manual transport path side guide member 871. And shorter than the length in the conveyance width direction.

  As a result, the direction of the curved protrusion formed on the paper T is regulated in the vicinity of the protruding portion 852 in the first transport path L1. Further, in the vicinity of the protruding portion 852 in the manual feed path La, the curve of the manual feed path La becomes gentle, so that the paper T is smoothly transported toward the registration roller pair 80.

Next, the operation of the printer 1 of the present embodiment will be briefly described with reference to FIG.
First, a case where single-sided printing is performed on the paper T stored in the paper feed cassette 52 will be described.
The paper T stored in the paper feed cassette 52 is sent out to the first transport path L1 by the forward feed roller 61 and the paper feed roller pair 81, and then the second transport section P2 and the first transport path L1 through the first transport path L1. The sheet is conveyed to the registration roller pair 80 by the one conveyance roller pair 82.
In the registration roller pair 80, skew correction of the paper T and timing adjustment with the toner image are performed.

The paper T discharged from the registration roller pair 80 is introduced between the intermediate transfer belt 7 and the secondary transfer roller 8 (secondary transfer nip N2) via the first conveyance path L1. A toner image is transferred onto the paper T between the intermediate transfer belt 7 and the secondary transfer roller 8.
Thereafter, the paper T is discharged from between the intermediate transfer belt 7 and the secondary transfer roller 8, and is interposed between the heating rotator 9a and the pressure rotator 9b in the fixing unit 9 via the second conveyance path L2. Introduced into the fixing nip. Then, the toner melts in the fixing nip, and the toner is fixed on the paper T.

Next, the paper T is transported to the paper discharge unit 50 through the third transport path L3, and is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1 by the discharge roller pair 53.
In this way, single-sided printing of the paper T stored in the paper feed cassette 52 is completed.

  When single-sided printing is performed on the paper T placed on the manual feed tray 65, the paper T placed on the manual feed tray 65 is sent out to the manual feed path La by the paper feed roller 66, and then the first joining portion. It is conveyed to the registration roller pair 80 via P1 and the first conveyance path L1. Subsequent operations are the same as the one-side printing operation of the paper T accommodated in the paper feed cassette 52 described above, and a description thereof will be omitted.

Next, the operation of the printer 1 when performing duplex printing will be described.
In the case of single-sided printing, as described above, the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 to the paper discharge stacking unit M1, and the printing operation is completed.
On the other hand, when performing double-sided printing, the paper T on which single-sided printing has been performed is reversed from the time of single-sided printing and conveyed again to the registration roller pair 80 via the return conveyance path Lb. Then, double-sided printing is performed on the paper T.

  More specifically, the operation is the same as the above-described single-sided printing operation until the paper T on which single-sided printing has been performed is discharged from the paper discharge unit 50 by the discharge roller pair 53. Thus, in the case of double-sided printing, in a state where the paper T on which single-sided printing has been performed is held by the discharge roller pair 53, the rotation of the discharge roller pair 53 is stopped and rotated in the reverse direction. When the discharge roller pair 53 is thus rotated in the reverse direction, the paper T held by the discharge roller pair 53 moves in the reverse direction (the direction from the paper discharge unit 50 toward the first branching unit Q1) along the third conveyance path L3. ).

  As described above, when the paper T is transported in the reverse direction on the third transport path L3, the paper T is rectified to the return transport path Lb by the rectifying member 58, and then, via the second junction P2. Then, it joins the first transport path L1. Here, the paper T is turned upside down from the one-side printing.

  Further, the paper T is subjected to the correction or the adjustment by the registration roller pair 80 and is introduced between the photosensitive drum 2 and the secondary transfer roller 8 through the first conveyance path L1. Since the unprinted surface of the sheet T passes through the return conveyance path Lb and faces the transfer roller 8, the toner image is transferred to the unprinted surface, and as a result, duplex printing is performed.

  Next, with reference to FIG. 3A to FIG. 3E, the conveyance operation of the paper T in the first conveyance path L <b> 1 that is a characteristic part of the printer 1 of the present embodiment will be described. FIG. 3A is a diagram illustrating a state in which the leading edge of the paper T sent to the first transport roller pair 82 is in contact with the protruding portion 852 in the printer 1 of the present embodiment. FIG. 3B is a diagram illustrating a state in which the leading edge of the paper T that is in contact with the protruding portion 852 is guided to the first conveyance path side guide member 861 side in the printer 1 of the present embodiment. FIG. 3C illustrates how the paper T is transported toward the registration roller pair 80 in a state where the paper T is curved so as to protrude toward the first transport path side guide member 861 in the printer 1 of the present embodiment. It is a figure to do. FIG. 3D is a diagram illustrating a state in which the sheet T abuts against the registration roller pair 80 in a state in which the sheet T has a curve protruding toward the first conveyance path side guide member 861 in the printer 1 of the present embodiment. It is. 3E shows a state in which the paper T is curved so as to protrude toward the first conveyance path side guide member 861 by being sent to the first conveyance roller pair 82 from the state shown in FIG. 3D in the printer 1 of the present embodiment. FIG. 10 is a diagram illustrating a state in which the sheet is curved along the first conveyance path side guide member 861.

  First, as shown in FIG. 3A, the paper T accommodated in the paper feed cassette 52 is sent out to the first transport path L1 by the forward feed roller 61 and the paper feed roller pair 81. The paper T sent out from the paper feed cassette 52 to the first transport path L1 is transported by the paper feed roller pair 81 toward the first transport roller pair 82 via the second junction P2. The paper T transported to the first transport roller pair 82 is sandwiched between the first transport roller pair 82 and sent out upward by the first transport roller pair 82 along the first transport path L1.

  Next, the paper T sent out by the first transport roller pair 82 abuts against the protruding portion 852 of the partition guide member 851 in a state where the paper T is disposed from the paper feed cassette 52 to the first transport roller pair 82.

  Thereafter, as shown in FIG. 3B, the leading edge of the paper T is guided to the first conveyance path side guide member 861 side by being sent out by the first conveyance roller pair 82. In this manner, the protruding portion 852 guides the paper T so that the paper T forms a curve that protrudes toward the first conveyance path side guide member 861.

  As illustrated in FIG. 3C, the paper T guided to the first conveyance path side guide member 861 side is conveyed toward the registration roller pair 80 along the first conveyance path side guide member 861. As a result, the paper T is formed with a (convex) curve that protrudes toward the first conveyance path side guide member 861.

  Further, since the curved protrusion formed on the paper T is formed so that the protruding portion 852 protrudes toward the first conveyance path side guide member 861 from the nip connection plane 880, the paper T is guided to the first conveyance path side. It is regulated so as not to protrude to the side opposite to the member 861, and the curved shape formed on the paper T is held in a state of protruding to the first conveyance path side guide member 861 side. That is, the paper T is transported toward the registration roller pair 80 while maintaining the curvature protruding toward the first transport path side guide member 861.

  Thereafter, the paper T is further transported toward the registration roller pair 80 by the first transport roller pair 82. As a result, the sheet T is conveyed toward the registration roller pair 80 while maintaining the direction in which the curved protrusion is formed by the protrusion 852.

  Next, as shown in FIG. 3D, the sheet T conveyed by the first conveyance roller pair 82 is conveyed along the first conveyance path side guide member 861 and contacts the registration nip N80 of the registration roller pair 80. Is done.

  Here, the registration nip plane 805 including the registration nip N80 formed on the registration roller pair 80 is closer to the first conveyance path side guide member 861 than the nip connection plane 880 on the upstream side in the conveyance direction of the registration roller pair 80. Be placed. Therefore, the sheet T that is in contact with the registration roller pair 80 toward the registration nip N80 abuts toward the registration nip N80 so that the curve formed on the sheet T protrudes toward the first conveyance path side guide member 861. . The sheet T is sent out by the first conveying roller pair 82 in a state where the leading end is in contact with the registration nip N80, so that the convex portion formed in a curve is easily arranged along the first conveying path side guide member 861. .

  Next, the paper T is sent out by the first conveying roller pair 82 in a state where the leading end is in contact with the registration nip N80. As a result, as shown in FIG. 3E, the sheet T is bent along the first conveyance path side guide member 861 in a state where the curve protruding to the first conveyance path side guide member 861 is formed on the sheet T. .

  By forming the curve in this way, the curve formed on the paper T has only one curve protrusion, and the formed curve has a simple protrusion. Therefore, the impact sound (abnormal noise) generated when the curve formed on the paper T abuts on the first conveyance path side guide member 861 is reduced in the direction where the number of times is small and the sound is small.

  Next, after skew correction and timing adjustment are performed, the skew-corrected sheet T is conveyed toward the image forming unit GK by the registration roller pair 80.

  Here, the skew formed on the paper T returns to a straight line when the paper T is skew-corrected and the paper T is conveyed by the registration roller pair 80. Abnormal noise generated when the curvature of the paper T returns to a straight line is small because the number of convex protrusions formed on the paper T is one and the shape of the curvature formed on the paper T is simple. It becomes. Therefore, the abnormal noise generated when the curve formed on the paper T in the skew correction returns to a straight line is reduced in a decreasing direction.

  By the way, the paper T printed by the printer 1 includes many types having different specifications and properties. The specifications and properties of the paper T include, for example, various sizes such as thickness, length, and width, rigidity (strength of stiffness), and friction coefficient. Due to different specifications and properties, the shape of the curve formed on the paper T differs.

  However, in the present invention, regardless of the specifications and properties of the paper T, the paper T to be conveyed is abutted against the protruding portion 852 so that the curved direction formed on the paper T (the direction in which the protrusion is formed). ) Can be guided to the first conveyance path side guide member 861 side. Further, the protruding portion 852 can hold the direction in which the curve formed on the paper T protrudes regardless of the specifications and properties of the paper T.

  As a result, the impact sound (abnormal noise) generated when the curvature formed on the paper T abuts against the first transport path side guide member 861 is reduced in a direction that decreases as the number of times decreases. Further, the abnormal noise generated when the paper T returns from the curved state to the straight state in the skew correction is reduced in a decreasing direction.

  In this way, regardless of the specifications and properties of the paper T, it is possible to reduce abnormal noise caused by forming a curve in skew (oblique feeding) correction. Accordingly, it is possible to reduce discomfort to surrounding users due to abnormal noise generated when the paper T is conveyed.

According to the printer 1 of the present embodiment, for example, the following effects are exhibited.
In the printer 1 of this embodiment, the paper feed cassette 52, the manual paper feed unit 64 different from the paper feed cassette 52, and the paper T accommodated in the paper feed cassette 52 are transported toward the image forming unit GK. One conveyance path L1, a pair of registration rollers 80 arranged in the first conveyance path L1, a first conveyance roller pair 82 that causes the leading edge of the paper T to abut against the registration roller pair 80 and curves the paper T, and manual feeding A manual feed path La that transports the paper T accommodated in the paper section 64 toward the registration roller pair 80, and a first manual feed path La that joins the first transport path L1 upstream of the registration roller pair 80; A plate-shaped partition guide member 851 disposed so as to partition the transport path L1 and the manual transport path La, and the partition guide member 851 is disposed on the first transport path L1 side so as to face the partition guide member 851. The first conveyance path side guide member 861 and the partition guide member 851 are formed on the downstream end side of the partition guide member 851 and on the first conveyance path side guide member 861 side with respect to the nip connection plane 880 connecting the registration nip N80 and the conveyance nip N82. And a protruding portion 852 that protrudes.

  Therefore, the protruding portion 852 can guide the protruding direction of the curvature formed on the paper T in a predetermined direction. In addition, the protrusion 852 can regulate and hold the curve formed to protrude in a predetermined direction. Thereby, the shape of the curve formed on the paper T can be simplified. Therefore, the impact sound (abnormal noise) generated when the curvature formed on the paper T abuts on the first conveyance path side guide member 861 is reduced. As a result, it is possible to reduce abnormal noise caused by curving the paper T in skew (oblique paper feeding) correction with a simple configuration.

  Further, since the shape of the curve formed on the paper T is simple, the noise generated when the curve formed on the paper T in the skew correction returns to a straight line is reduced in a decreasing direction. As a result, it is possible to reduce abnormal noise resulting from the curving of the paper T in skew (oblique paper feeding) correction with a simple configuration.

  In the printer 1 of the present embodiment, the protruding portion 852 guides the paper T so that the paper T forms a curve that protrudes toward the first transport path side guide member 861. For this reason, the leading edge of the sheet T abuts and is guided to form a curve that protrudes toward the first conveyance path side guide member 861. As a result, the paper T is curved in a direction protruding toward the first conveyance path side guide member 861, and noise caused by the paper T being curved in skew (oblique feeding) correction is reduced with a simple configuration. be able to.

  In the printer 1 of the present embodiment, the registration nip plane 805 including the registration nip N80 is formed on the first conveyance path side guide member 861 side with respect to the nip connection plane 880 on the upstream side in the conveyance direction of the registration roller pair 80. The For this reason, the paper T that is in contact with the registration nip N80 is likely to be formed in a shape in which the curve protrudes (becomes convex) toward the first conveyance path side guide member 861. As a result, the curve formed on the paper T can be shaped to protrude toward the first conveyance path side guide member 861. Accordingly, it is possible to further reduce noise caused by the skew of the paper T in skew (oblique paper feeding) correction with a simple configuration.

  In the printer 1 of the present embodiment, the conveyance nip plane 825 including the conveyance nip N82 is closer to the first conveyance path side guide member 861 than the nip connection plane 880 on the downstream side in the conveyance direction of the first conveyance roller pair 82. It is formed. Therefore, the paper T conveyed by the first conveyance roller pair 82 is conveyed toward the first conveyance path side guide member 861 side. Accordingly, the paper T is easily guided to form a curve that protrudes toward the first conveyance path side guide member 861. As a result, the curve formed on the paper T can be shaped to protrude toward the first conveyance path side guide member 861. Abnormal noise resulting from the curvature of the paper T in skew (oblique paper feeding) correction can be further reduced with a simple configuration.

  In the printer 1 of the present embodiment, the protruding portion 852 is disposed closer to the resist nip N80 than the position where the distance from the resist nip N80 and the transport nip N82 is equal on the nip connection plane 880. Therefore, the protrusion 852 is disposed in the vicinity of the registration nip N80 in the registration roller pair 80. Thereby, the curve which protrudes in the 1st conveyance path side guide member 861 side can be hold | maintained only by making the protrusion part 852 protrude slightly with respect to the nip connection plane 880. FIG.

As mentioned above, although preferred embodiment of this invention was described, this invention can be implemented with a various form, without being limited to embodiment mentioned above.
For example, in the above-described embodiment, the main storage unit is configured as the paper feed cassette 52 and the sub storage unit is configured as the manual paper feed unit 64, but is not limited thereto. For example, the main storage unit may be configured as the manual paper feed unit 64 and the secondary storage unit may be configured as the paper feed cassette 52.

The embodiment is a so-called indirect transfer type image forming apparatus, and the transfer nip is formed as the secondary transfer nip N2 between the intermediate transfer belt and the secondary transfer roller, but is not limited thereto. For example, in the case of a direct transfer type image forming apparatus, the transfer nip is formed, for example, between a photosensitive drum and a transfer roller.
The type of the image forming apparatus of the present invention is not particularly limited, and may be a copier, a printer, a facsimile, or a complex machine thereof.
The sheet-shaped transfer material is not limited to paper, and may be a film sheet, for example.

  DESCRIPTION OF SYMBOLS 1 ... Printer (image forming apparatus) 52 ... Paper feed cassette (main accommodating part) 64 ... Manual paper feeding part (sub-accommodating part), 80 ... Registration roller pair, 82 ... First conveyance roller pair (Conveying roller pair), 801... Registration driving roller, 802 .. registration opposing roller, 805 .. registration nip plane, 821 .. conveying driving roller, 822 .. conveyance opposing roller, 825. ... partition guide member (guide member), 852 ... projection, 861 ... first transport path side guide member (main transport path side guide member), 880 ... nip connection plane, GK ... image forming section, L1 ... first 1 transport path (main transport path), La... Manual feed path (sub transport path), N80... Registration nip, N82... Transport nip, T.

Claims (6)

An image forming unit for forming an image on a sheet-like transfer material;
A main accommodating portion for accommodating the transfer material;
A sub-accommodating portion that accommodates the transfer material and is different from the main accommodating portion;
A main conveyance path for conveying the material to be transferred accommodated in the main accommodation portion toward the image forming portion;
A pair of registration rollers disposed in the main conveyance path and forming a registration nip, and a pair of registration rollers for feeding the transfer material toward the image forming unit;
A pair of conveying rollers disposed on the main accommodating portion side of the pair of registration rollers in the main conveying path and forming a conveyance nip, wherein a tip of the material to be transferred is brought into contact with the pair of registration rollers and the object to be transferred A pair of transport rollers for curving the material,
A sub-transport path for transporting the transfer material accommodated in the sub-accommodating section toward the registration roller pair, and joins the main transport path on the upstream side of the transfer direction of the transfer material in the registration roller pair. A sub-transport path to
A plate-like guide member that is arranged so as to partition the main transport path and the sub-transport path, and guides the transfer material transported in the sub-transport path toward the registration roller pair;
A main conveyance path-side guide member that is arranged on the main conveyance path side with respect to the guide member, and that guides the transfer material conveyed in the main conveyance path toward the pair of registration rollers;
A projecting portion that is formed on the leading end side of the guide member on the downstream side in the transport direction and projects toward the main transport path side guide member side with respect to a nip connection plane that connects the registration nip and the transport nip ,
The registration roller pair includes a registration driving roller and a registration facing roller that is disposed to face or contact the registration driving roller.
The conveyance roller pair includes a conveyance drive roller disposed on the opposite side of the registration drive roller with respect to the nip connection plane, and a conveyance counter roller disposed adjacent to or in contact with the conveyance drive roller. <br/> Image forming apparatus. The image forming apparatus according to claim 1, wherein the protrusion guides the transfer material such that the transfer material forms a curve protruding toward the main conveyance path side guide member. The image according to claim 1, wherein a registration nip plane including the registration nip is formed on the main conveyance path side guide member side with respect to the nip connection plane on an upstream side in the conveyance direction of the registration roller pair. Forming equipment. The conveyance nip plane including the conveyance nip is formed on the main conveyance path side guide member side with respect to the nip connection plane on the downstream side in the conveyance direction of the conveyance roller pair. The image forming apparatus described. 5. The image forming apparatus according to claim 1, wherein the protrusion is disposed on the resist nip side of a position where the distance from the resist nip and the transport nip is equal in the nip connection plane. The registration driving roller is formed of a material that does not substantially deform in a portion where the registration nip is formed,
The resist facing roller is formed of a material having flexibility and elasticity in a portion where the resist nip is formed,
The transport driving roller is formed of a material that does not substantially deform in a portion that forms the transport nip,
The image forming apparatus according to claim 1, wherein the conveyance facing roller is formed of a material having flexibility and elasticity at a portion where the conveyance nip is formed.

Images