JP3371762B2 - Print medium transport device and color image forming device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print medium conveying device and a color image forming apparatus for feeding a print medium to an image transfer position, and more particularly to an operation for removing a print medium jammed near the image transfer position. The present invention relates to a print medium conveying device having improved property.

[0002]

2. Description of the Related Art In an image forming apparatus such as a printer or a copying machine, for example, recording paper as a printing medium stored in a paper feed cassette is conveyed to an image transfer position by a recording paper conveying device. FIG. 7 is a cross-sectional view of a main part of the recording paper transportation device. In the recording paper conveying device, the guide members 1, 2, 3, 4, 5, 6
Thus, a transport path through which the recording paper P passes is formed. Recording paper P pulled out from a paper feed cassette (not shown)
Are the transport rolls 7, 8, 9, which are arranged in the middle of the transport path.
An image transfer position, that is, a drum-shaped photoconductor 11 by 10
And the transfer device 12 are fed.

In order to transfer the image on the photoconductor 11 to a desired position on the recording paper P, the recording paper P must be fed to the image transfer position at a precisely set timing. An optical sensor 13 as a recording paper detection sensor is arranged below the guide member 4, and the recording paper P is detected based on the presence or absence of light reflected by passing through a through hole 4a provided in the guide member 4. To be done. In order to feed the recording paper P to the image transfer position at a desired timing, the transport rolls 9 and 10 are urged based on the detection signal from the optical sensor 13 and the image formation timing on the photoconductor 11. The transport rolls 9 and 10 provided immediately before the image transfer position are called resist rolls or registration rolls, and the transport rolls 7 and 8 immediately before that are called pre-registration rolls or pre-registration rolls. The recording paper P having the toner image transferred at the image transfer position is heated and fixed by the fixing device 14 and then output to a discharge tray (not shown).

[0004]

Generally, in a print medium conveying device, the shapes and materials of the guide member and the convey roller, and various conditions for driving the convey roller are provided so that the print medium is not clogged in the convey path. Are selected or set with due consideration. However, due to changes in the quality of the print medium due to changes in the usage environment such as the type of print medium, changes in temperature and humidity, and the like, clogging of the print medium may occur in the transport path despite the above considerations. .

When a print medium is clogged, image formation cannot be continued unless the print medium is removed from the conveyance path. For example, in FIG. 4, when the recording paper P is jammed in the conveyance path, the recording paper P is pulled out in the axial direction of the conveyance rollers 7 to 9 and removed. However, it may be difficult for the operator to operate from this axial direction. Therefore, in order to remove the recording paper P in the transport path by operating from above the transport path, it is conceivable that the guide members 3 and 5 can be opened and closed upward, for example. JP-A-8-91
In Japanese Patent Laid-Open No. 637 and Japanese Patent Laid-Open No. 8-95324,
Disclosed is a transport device in which a guide member (corresponding to the guide member 3 in FIG. 7) that forms a transport path on the upstream side of the registration roll pair, that is, on the side opposite to the image transfer position when viewed from the registration roll pair is openable and closable.

However, simply opening and closing the guide member 3 is not sufficient from the viewpoint of operability, and the following problems associated with the removal of the recording paper P still remain. A problem occurs when the leading edge of the recording paper P passes through the transfer device 12, that is, when the recording paper P is jammed in a state where the toner image is transferred onto a part of the recording paper P. In this case, the guide member 3 is opened and the recording paper P jammed in the conveying path
When the sheet is pulled out, the unfixed toner transferred to the leading end portion of the recording paper P adheres to the guide member 5 and the resist rolls 9 and 10, and the recording paper conveyed thereafter is soiled by the unfixed toner. There is.

It is conceivable that the guide member 5 can be opened upward similarly to the guide member 3, as shown in FIG.
As will be understood from above, the photoconductor 1 is provided above the guide member 5.
1 is located and this guide member 5 cannot be opened.

Further, three primary color toner images (primary transfer images) are sequentially formed on the drum-shaped primary photoconductor in plural times.
In a color image forming apparatus in which this primary transfer image is transferred onto a belt-shaped secondary photoconductor in an overlapping manner and then secondarily transferred onto a recording paper to finally obtain a full-color image,
Particularly, since the belt-shaped secondary photoconductor exists above the guide member 5, it is extremely difficult to open the guide member 5. Since the secondary photoconductor is made of an extremely thin film-like material, the advancing angle of the recording paper to the image transfer position, that is, the contact angle with the secondary photoconductor is made small so that the secondary photoconductor is located at the leading edge of the recording paper. You need to make sure that it is not scratched. If the contact angle is reduced, the secondary photoconductor will be arranged in a state of being directly above the guide member 5, and it will be more difficult to open the guide member 5 upward.

The present invention solves the above problems, and when a print medium is jammed, the jammed print medium is easily removed while preventing the print medium conveying path from being soiled with unfixed toner. It is an object of the present invention to provide a print medium conveying device and a color image forming apparatus that can perform the above.

[0010]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems and for achieving the object, is provided immediately before the image transfer position in order to convey the print medium to the image transfer position of the image forming apparatus. In the print medium conveying device, a lower guide member and an upper guide member that form a conveying path for guiding the print medium, a frame on which the lower guide member and the upper guide member are mounted, and the frame are inserted into and removed from the image forming apparatus. It is characterized in that it is provided with a carrier device assembly which is composed of a holding means for holding it possible.

According to the above features, the transport device assembly can be freely inserted into and removed from the image forming apparatus. Therefore,
For example, when the print medium is jammed, if the transport device assembly is pulled out from the image forming apparatus, the upper part of the transport device assembly is opened, and a space for removing the jammed print medium is secured.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. 3 and 4 are sectional views showing the outline of a full-color image forming apparatus including a recording sheet conveying apparatus according to an embodiment of the present invention. 3 and 4, the photoconductor 11
Well-known components (not shown) for electrophotographic image formation such as a charger, a laser scanner, a developing device, and a cleaner are arranged around the periphery of the. The photoconductor 11 is uniformly charged by a charger and is irradiated with laser light modulated by a laser scanner based on image data to form an electrostatic latent image on the photoconductor 11. The formed electrostatic latent image is developed with a toner of a predetermined color in the developing device.

The photoreceptor 11 has a plurality of rolls 15, 1
An intermediate transfer device 21 including a belt 20 as a secondary photosensitive member stretched around 6, 17, 18, and 19 is arranged adjacent to each other. The roll 16 is pressed against the photoconductor 11 via the belt 20 and is provided to transfer the toner image on the photoconductor 11 to the belt 20 (primary transfer) by charging the belt 20 with a polarity opposite to that of the toner. Has been.

On the other hand, a secondary transfer roll 22 is disposed opposite to the roll 18 with the belt 20 interposed therebetween, and the secondary transfer roll 22 has been transferred to a position between the secondary transfer roll 22 and the roll 18, that is, a secondary transfer position. The toner image on the belt 20 is transferred onto the recording paper. The recording papers are stored in a paper feed cassette 23 in a stacked state, and are fed to a transport device assembly (hereinafter referred to as a "registration unit") 25 by a paper feed roll 24 in order from the uppermost one.

A registration roll pair 9, 10 and a pre-registration roll pair 7, 8 and a first-stage transport roll 27 are rotatably attached to a frame 26 of the registration unit 25. The transport roll 27 is paired with a transport roll 28 provided on the image forming apparatus main body side, and the transport roll 28 is connected to a driving unit (not shown). That is, the roll 27 is pressed by the roll 28 and rotates following the roll 28. The registration roll pairs 9 and 10 and the pre-registration roll pairs 7 and 8 are connected to driving means (not shown) such as a motor via a gear train described later. The frame 26 of the cash register unit 25 is the frame body 2 of the image forming apparatus.
The rail 9 is slidably engaged with the rail 9 via a rail 30 and is held so that it can be inserted into and removed from the image forming apparatus in the recording paper conveyance direction. FIG. 4 shows a state in which the registration unit 25 is pulled out from the frame body 29. As can be seen from the figure, when the cash register unit 25 is pulled out, the upper part of the cash register unit 25 is open, so that it is easy for a person to intervene in the recording paper transport path. . When pulling out the cash register unit 25, the frame 2
The fingertip may be hooked on the recess 26a formed on the surface of 6.

A position restricting member (stopper) 32 is fixed to the frame body 29 so that when the frame 26 of the cash register unit 25 is pushed into the frame body 29, the protruding member 31 provided at the tip of the frame 26 abuts. . The position of the stopper 32 is such that, when the frame 26 is pushed into the frame main body 29, the most distal end of the frame 26, that is, the end of the frame 26 on the image transfer position side is at a suitable distance from the image transfer position. Determined to be set. The cash register unit 25 will be described in more detail later.

The recording paper fed from the paper feed cassette 23 reaches the image transfer position along the conveyance path shown by the dotted line, and the toner image on the belt 20 is transferred onto the recording paper by the action of the secondary transfer roll 22. The toner image transferred onto the recording paper is heated and fixed by the fixing roll pair 33, and the discharge tray 3
4, that is, the upper surface of the frame body 29 or the discharge tray 3
It is discharged to 5. The discharge tray 34 is a so-called face-down tray in which the image transfer surface of the recording paper is discharged downward, and the discharge tray 35 is a so-called face-up tray in which the image transfer surface is discharged upward. The recording paper on which printing has been completed is conveyed to the discharge tray 34 by the roll pairs 36, 37 and 38. On the other hand, the recording paper on which printing has been completed is conveyed to the discharge tray 35 by the roll pairs 36 and 39. A gate (not shown) for switching the transport path is provided downstream of the roll pair 36, and the switching of the gate determines whether face down or face up is selected.

Next, the structure of the cash register unit 25 will be described in more detail. 1 is an enlarged view of a main part of the cash register unit 25 mounted on the frame main body 29, and FIG. 2 is a perspective view of the cash register unit 25. The same reference numerals as those in FIG. FIG. 1 is a sectional view taken along the line 1-1 ′ of FIG. In FIGS. 1 and 2, the frame 26 has a lower chute 40 that forms a part of a conveyance path through which recording paper passes. The lower chute 40 is preferably made of resin for weight saving, and a plurality of ridges 41, that is, convex portions extending in the recording paper conveyance direction are provided on the upper surface. Since the recording paper comes to be conveyed in contact with the top of the ridge 41, the contact area with the recording paper can be reduced and the sliding property thereof is improved.

The registration rolls 9 and 10 are rotatably supported by the side plates 42 and 43 of the frame 26. On the other hand, the surface of the register roll 10 is made of rubber, for example, and the shaft 10a supported by the side plates 42 and 43 passes through the center thereof. One end of the shaft 10a penetrates the side plate 43, a gear 44 is fixed to the penetrating end, and power is transmitted to the shaft 10a via the gear 44. It is preferable that at least the surface of the driven-side register roll 9, that is, the nip-side register roll, is formed of a hard and smooth metal in order to prevent catching when the leading end of the fed recording paper hits.

The shaft 9a of the registration roller 9 on the nip side is a side plate 42.
At the end of the shaft 9a outside the side plate 42, a friction member 9b arranged so as to be in contact with the side plate 42 is provided in order to suppress the rotation of the registration roll 9. The side plate 42 has a handle 45 attached to its shaft (not shown) so that the pre-registration roll 8 (see FIG. 3) can be manually rotated.

The upper chute 46, ie, the baffle, which constitutes a part of the conveying path through which the recording paper passes, covers the lower chute 40 including the registration roll 9 almost entirely on the downstream side of the pre-registration rolls 7 and 8. There is. Baffle 46
Of the side plates 42, 43 on the upstream side of the recording paper conveyance direction.
A flange 47 that extends vertically from the upper surface of the baffle 46 is provided so as to follow. A long hole 47a is formed in the flange 47 in the up-down direction, and a shaft 48 erected on the side plate 43 is passed through the long hole 47a.
Therefore, the baffle 46 is supported rotatably around the shaft 48. It goes without saying that this support structure is similarly provided on the side plate 42 side. Baffle 46
The upper surface of the handle 4 is used to open and close the baffle 46.
9 is provided.

Above the pre-registration rolls 7 (not shown in FIGS. 1 and 2), a plurality of rib-like chutes 50 (only two of which are formed to form a conveying path in the vicinity of the pre-registration rolls are designated by reference numerals). ) Is supported and arranged by the support plate 51. Both ends of the support plate 51 are fixed to the side plates 42 and 43. The recording paper is fed between the pre-registration rolls 7 and 8 (see FIG. 3) through a conveyance path formed by the rib-shaped chute 50 and the extension 52 of the lower chute 40.

The conveying path formed by the baffle 46 and the lower chute 40 is not a simple shape as shown in the cross section of FIG. First, immediately after the pre-registration roll, a flat transport path A having a substantially uniform gap is formed, but thereafter, there is a slightly upwardly directed portion B, and further, a portion C which rolls downward is provided. Have. This transport path B and C
Curls or bends are imparted to the recording paper passing therethrough. Furthermore, behind the cashier rolls 9 and 10,
After passing through a flat conveyance path D having a substantially uniform gap, a portion E where the gap is gradually reduced is reached, and a discharge is left at the leading end so that a gap that is sufficient and not too large for one sheet of recording paper to pass through is left. The part F is formed. The gap of the discharge portion F can be ensured by making two of both ends of the plurality of ridges 41 higher than the other ridges in consideration of the thickness of the recording paper.

FIG. 6 is an enlarged front view of the discharge portion F, that is, the leading end of the conveying path. As shown in the figure, the two ridges 41a, 41b located on both sides in the width direction of the transport path are made higher than the remaining ridges 41c, ..., 41h arranged in the middle part. Therefore, when the baffle 46 is pressed by the lower shooter 40, the lower surface of the baffle 46 abuts only on the two ridges 41a and 41b, and between the upper surfaces of the other ridges 41c, ..., 41h and the lower surface of the baffle 46. There is formed a gap through which the recording paper P can pass.

A protrusion member 31 for positioning is provided outside the extension portions 42a, 43a of the side plates 42, 43 (the extension portion 43 side is not shown).
The registration unit 25 is accurately positioned by bringing 1 into contact with the stopper 32 as described above. Baffles 46 are formed with outwardly projecting portions 53 and 54 at both ends thereof. The protruding portions 53 and 54 are formed on the registration unit 2 until the protruding member 31 contacts the stopper 32.
When 5 is pushed into the image forming apparatus, it is pushed down by engaging with the lower surfaces of the pressing members 55 and 56 fixed in the image forming apparatus, and the tip of the baffle 46 is the ridges 41a and 41b of the lower chute 40. Is pressed by. As a result, in the state where the registration unit 25 is set at the planned position for carrying the recording paper, the carrying path formed by the baffle 46 and the lower chute 40 is maintained at the planned gap.

The rail 30 is attached to the lower outside of the side plate 42. The rail 30 is composed of a portion 30a fixed to the frame 26 of the cash register unit and a portion 30b fixed to the inside of the frame body 29 of the image forming apparatus via a metal fitting 57, and these portions 30a and 30b are recorded. They are formed so as to be slidable in the paper transport direction. The registration unit 25 can be freely inserted into and removed from the image forming apparatus by the rail 30. Rail 30 is part 30
The number of stages is not limited to two, and the number of stages can be further increased. The rail is also provided outside the side plate 43.

The gears 58, 59, 60, together with the gear 44 and other gears (not shown), form a gear train for transmitting power to the registration roll 9 and the pre-registration roll 7. One of the gears 58 to 60 and other gears (not shown) when the register unit 25 is set to a predetermined operation position.
Is coupled to the shaft of a drive motor provided on the image forming apparatus side, and power is transmitted. The gear 6 has a clutch 6
1 is attached, and a clutch is also provided between the drive motor and the drive motor, if necessary.

In the above structure, the paper feeding cassette 23
The recording paper sent out from the recording paper passes through the pre-registration rolls 7 and 8 and then reaches the registration rolls 9 and 10. Here, the recording paper is conveyed along the baffle 46 forming the upper surface of the conveyance path C when passing the conveyance paths B and C forming the chevron just before the registration rolls 9 and 10. Therefore, the leading edge of the recording paper hits the metal registration roll 9 and the registration roll 9
It is fed into the gap (nip portion) between the registration roll 9 and the rubber-made registration roll 10 while sliding on the surface thereof. By this operation, skew or skew of the recording paper is eliminated.
When the leading end is located between the registration rolls 9 and 10, the conveyance is temporarily stopped and waits for a command from the control unit of the image forming apparatus. Then, in response to the command, the clutch 61 is engaged, the registration rollers 9 and 10 are rotated, and the recording paper is conveyed to the image transfer position.

Next, the procedure for the case where the recording paper is jammed in the transport path in the register unit 25 will be described with reference to FIG. FIG. 5 is a cross-sectional view of the registration unit 25 pulled out from the image forming apparatus, and particularly shows an opening mode of the baffle 46. When the recording paper is jammed in the conveyance path in the register unit 25, first, the concave portion 26a on the surface of the frame 26 is touched and the register unit 25 is pulled out from the image forming apparatus. At this time, the projecting portions 53 and 54 of the baffle 46 are separated from the pressing members 55 and 56, and the pressing force on the lower chute 40 is released. Since the registration unit 25 slides smoothly on the frame body 29 of the image forming apparatus via the rail 30, it can be easily pulled out. When the registration unit 25 is pulled out from the image forming apparatus to some extent or completely, the intermediate transfer device 21, which is positioned so as to cover the baffle 46, is present above the baffle 46 as illustrated. Disappear.

When a large free space is secured in the register unit 25, especially above the baffle 46, the handle 49 is used to lift the baffle 46. At this time, if the baffle 46 is lifted with the shaft 48 positioned above the elongated hole 47a of the flange 47, the baffle 46 rotates about the shaft 48 and the conveyance path is opened (state G1). When the baffle 46 is lifted as in the state G1, the end of the baffle 46, that is, the end near the pre-registration roll may interfere with the lower chute 40. Therefore, in order to avoid this, the mounting position of the shaft 48 and the shape of the flange 47 are limited.

Therefore, in this embodiment, a long hole 47a is provided so that the flange 47 can move up and down with respect to the shaft 48. When the baffle 46 is lifted, the movement of the hand is adjusted so that the flange 47 side of the baffle 46 is lifted first, and the elongated hole 47a is slid with respect to the shaft 48 to lift the flange 47. Thus, the baffle 46
After a space is secured below the baffle 46 near the center of rotation, the baffle 46 is rotated about the shaft 48 to largely open the conveyance path (state G2). When the transport path is opened, the jammed recording paper is taken out upward and removed from the transport path.

As described above, according to this embodiment, the cash register unit 25 is pulled out from the image forming apparatus and the baffle 4 is used.
The jammed recording paper can be easily removed by lifting 6. At this time, since the baffle 46 is lifted, it is possible to remove the recording paper without adhering the unfixed toner transferred to the leading end of the recording paper to each component inside the registration unit 25 such as the leading end of the baffle. .

The above is one example of the embodiment of the present invention,
The present embodiment can be modified without departing from the scope of the present invention. For example, the support portion of the baffle 46 is not limited to the fitting of the pivot and the elongated hole, but may be the fitting of the pivot and the circular hole that supports the pivot. That is, the center of rotation of the baffle 46 does not necessarily have to be deviated. Further, when the register unit 25 is mounted on the image forming apparatus, the projecting portions 53 and 54 of the baffle 46 are pressed to ensure the predetermined transport path gap, but the pressing mechanism is not necessarily limited to such a pressing mechanism. The tip of the baffle 46 may be fixed to the lower chute 40 by screwing. According to the present invention, the cash register unit 25 can be inserted into and removed from the image forming apparatus to increase the degree of freedom of operation of the operator from above the transport path.
Even if the tip of the baffle is screwed, the screw can be easily attached and detached. Therefore, the operability for removing the jammed recording paper by removing the screw is improved in each step as compared with the conventional apparatus.

Further, the transfer device is a resist roll 9, 1.
The present invention is not limited to those having 0 and the pre-registration rolls 7 and 8, and can be applied to an image forming apparatus configured to directly feed the recording paper from the transport roll 27 to the image transfer position. In that case, the baffle 46 may be a flat one as a whole without a bend, and at least the tip portion may have a tapered portion, that is, the discharge portion F.

[0035]

As is apparent from the above description, according to the present invention, the conveying device assembly provided immediately before the image transfer position can be easily pulled out from the image forming apparatus. Therefore, for example, when the recording paper is jammed, it is possible to secure a wide working space on the transport device assembly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a carrier device assembly according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of the carrier device assembly according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view of an image forming apparatus including a conveyance device assembly.

FIG. 4 is a cross-sectional view of the image forming apparatus with a transport device assembly pulled out.

FIG. 5 is a cross-sectional view showing a conveyance device assembly pulled out from the image forming apparatus.

FIG. 6 is an enlarged front view of the transport device assembly showing the transport path tip.

FIG. 7 is a schematic diagram of an image forming apparatus including a conventional conveying device.

[Explanation of symbols]

9, 10 ... Cash register roll, 26 ... Frame, 30 ... Rail, 31 ... Projection member, 40 ... Lower chute, 41
... ridges, 42, 43 ... side plates, 47 ... flanges, 47
a ... long hole, 48 ... shaft, 49 ... handle, 50 ... rib,
53, 54 ... Overhanging part

Continuation of the front page (56) References JP-A-60-68352 (JP, A) JP-A-3-120141 (JP, A) Actually opened 61-72535 (JP, U) Actually opened 60-122735 (JP , U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B65H 5/00-5/38 G03G 15/00

Claims (2)

(57) [Claims] 1. A print medium transport device provided immediately before the image transfer position for transporting the print medium from the print medium cassette to an image transfer position of the image forming apparatus, wherein the print medium is above the print medium cassette. A lower guide member and an upper guide member that are arranged so as to overlap the cassette and that form a first transport path that guides the print medium; and a vertical direction that guides the print medium of the print medium cassette to the upper first transport path. A second transport path, a transport roll pair that transports the print medium on the second transport path, a frame on which the lower guide member, the upper guide member, and one transport roll of the transport roll pair are mounted, and the frame image A transporting device assembly comprising a holding means for holding the forming device linearly so that the frame can be pulled out and inserted; and the frame is pulled out from the image forming device. The transfer position of the print medium cassette and the interval between the transfer device assembly are increased in the transfer direction of the print medium in the first transfer path, and the interval between the transfer rolls of the transfer roll pair is A print medium conveying device, wherein the frame insertion / removal direction is determined so as to expand in a direction perpendicular to the surface of the print medium passing through the pair of conveyance rolls. 2. A registration roll pair mounted on the frame and provided on the first transport path, and a pre-registration roll pair provided at a stage prior to the registration roll pair, wherein the upper guide member comprises: The first guide path is formed to cover the lower guide member together with the resist roll pair in front of and behind the resist roll pair, and the upper guide member is rotatably supported in the opening / closing direction of the first carrier path. In order to achieve this, a pivot further provided near the pre-registration roll is further provided, and an overhanging portion that extends horizontally orthogonal to the print medium transport direction is formed at the tip of the upper guide member. Engages with an engaging member in the image forming apparatus when the transport device assembly is pushed into a predetermined position of the image forming apparatus so that the upper guide member pushes against the lower guide member. Is the one, the printing medium conveying apparatus according to claim 1, characterized in that are arranged so that the pressing force is released when the drawer the conveyor assembly from the image forming apparatus.