JP3261890B2 - 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 an image forming apparatus which forms an image on a recording sheet and discharges it outside the apparatus, such as a printer, a copying machine or a facsimile machine.
The present invention relates to an image forming apparatus capable of orderly aligning large-size recording paper on a discharge tray.

[0002]

2. Description of the Related Art In a large-sized electronic copying machine or the like that handles large-sized paper such as A0 size or A1 size, unlike a conventional electronic copying machine using cut paper, a roll paper is mounted in a roll paper storage unit. The roll paper is cut into a predetermined length based on the length information of the document, and this is used as recording paper.

By the way, it is desirable that a discharge roller is provided at the last stage of the paper transport path, and that the recording paper discharged to the outside by the discharge roller is arranged in order on a discharge tray. However, especially in the case of large-size recording paper or thin recording paper, the so-called "stiffness" is so weak that the leading end portion hangs during ejection. For this reason, there is a problem that the recording paper already discharged on the discharge tray is dragged, and it is difficult to arrange the discharged recording paper on the discharge tray in an orderly manner.

In order to solve such a problem, conventionally, in order to impart “stiffness” to the discharged recording paper by corrugation (giving wavy “wrinkles”),
The shape of the discharge roller is devised. FIG. 8 is a diagram showing a configuration of a conventional discharge roller, and FIG.
FIG. 2B is a side view.

The discharge roller 43 is composed of a combination of a convex roller 431 and a concave roller 432,
0 is the first nip point P1 between the non-convex portion 431b of the convex roller 431 and the non-concave portion 432a of the concave roller 432,
And the convex portion 431a of the convex roller 431 and the concave roller 4
The nip is formed by a second nip point P2 formed by the 32 concave portions 432b.

On the other hand, the relative positional relationship between the paper transport path 60 and the discharge roller 43 is defined so that a second nip point P2 is formed on an extension plane of the inner lower surface of the paper transport path 60. . Accordingly, the recording paper 20 is given a “stiffness” by the corrugation action as shown in the drawing, and the leading end of the recording paper 20 does not hang down during discharge, so that the recording paper 20 is arranged neatly on the discharge tray. Becomes possible.

[0007]

The final stage of the paper transport path 60 is curved in accordance with the position of the discharge tray after rising up from below so that the recording paper is discharged onto the discharge tray. Here, due to space restrictions, the discharge roller 43 is often provided at a position immediately after the sheet conveying path 60 is curved. At this time, the recording paper 20 transported in the paper transport path 60 is, as shown in FIG.
The curved portion abuts against the inner upper surface of the paper transport path 60, and is thereafter guided to the discharge roller 43 using the inner upper surface as a guide plate.

Accordingly, as shown in FIG. 8 (a), the depth of corrugation by the discharge roller 43 substantially matches the inner diameter H1 of the paper transport path 60, and the width W1 is also increased.
Unnecessarily large corrugations will occur. For this reason, the corrugation is caused by the inflection point 6 of the recording paper 20.
In this case, the recording paper 20 may reach the upstream side, and in some cases, may reach the curved portion of the paper transport path, causing a streak-like damage to the recording paper 20.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide a sufficient corrugation action without damaging the recording paper, so that the recording paper can be arranged neatly on a discharge tray. It is to provide a device.

[0010]

According to the present invention, there is provided an image forming apparatus for forming an image on a recording sheet and discharging the recording sheet from a discharge port to the outside of the apparatus. A discharge roller that discharges the recording paper guided along the outside by a concave and a convex roller engaged with each other, and a first nip formed by a non-recess portion of the concave roller and a non-convex portion of the convex roller. Discharge roller so that the first nip point among the second nip points formed by the point and the concave portion of the concave roller and the convex portion of the convex roller is located on the extension plane of the paper guide surface of the paper guide means. It is characterized in that the relative position between the sheet guide means and the sheet guide means is defined.

[0011]

According to the above construction, the first nip point of the discharge roller is generated on the extension plane of the paper guide surface of the paper guide means, so that the first nip point and the second nip are formed on the recording paper. Corrugation of a depth corresponding to the height difference from the point occurs by the width of each roller. Therefore, the length of corrugation can be shortened, and the generation of streaks due to corrugation is prevented.

[0012]

FIG. 1 is a perspective view of a large-sized printer to which a roll paper feeder according to the present invention is applied, and an image forming apparatus 1 for forming an image on a recording paper, and a roll paper is supplied to the image forming apparatus 1. The image forming apparatus 1 includes a roll paper feeder 3 and cut paper feeders 4 and 5 for supplying cut paper to the image forming apparatus 1. The recording paper after image formation is discharged onto a recording paper discharge tray 7 provided at the top of the printer.

A plurality of roll papers can be stored in the roll paper feeder 3. As will be described in detail later, image formation is performed while cutting the paper drawn from each roll paper to a predetermined length. A mechanism for feeding paper to the unit 1 is provided. Similarly, the cut sheet feeding devices 4 and 5 are provided with a mechanism that feeds the stacked cut sheets to the image forming unit 1 while separating the cut sheets one by one. Further, a manual paper feed unit 6 is provided on a side surface of the image forming apparatus 1, and it is also possible to manually supply cut paper. A message such as a paper jam or an out of paper is displayed on the operation display unit 8 of the image forming apparatus 1.

FIG. 2 is a perspective view showing a state in which the roll paper feeder 3 is pulled out of the printer main body. In this embodiment, two roll papers 11a and 11b are stored. A rail mechanism 10 is provided on a side surface of the roll paper feeder 3, and the roll paper feeder 3 is configured to be pulled out by the rail mechanism 10 in a direction perpendicular to the roll paper transport direction.

Although the cut sheet feeders 4 and 5 can be pulled out from the printer main body in the same manner as the roll sheet feeder 3, they are not shown here. A paper quality selection switch 17 and a paper type selection switch 18 are provided on the front upper portion of the roll paper feeding device 3 for each roll paper. When the roll paper is set, the paper quality of the paper and the roll used are set. Which paper is registered is registered.

FIG. 3 is a cross-sectional view showing a schematic configuration of a paper transport path inside the printer. In the roll paper feeding device 3, the recording paper 20 fed from the roll papers 11 a and 11 b by the feed roller 22 forms an image via a rotary cutter 25 and a transport roller 36 disposed on a paper transport path 23. The paper is supplied into the paper transport path 24 of the apparatus 1. On the other hand, the cut sheet feeding devices 4, 5
Then, the stacked cut papers 30a and 30b are drawn into the paper transport path 32 one by one, and are transported by the transport rollers 31a to 31e.
Is supplied to the inside of the image forming apparatus 1.

In the image forming apparatus 1, the recording paper 20 fed into the paper transport path 24 is transported downstream by the transport roller 51, reaches the image transfer unit via the registration roller device 27, and forms the photosensitive drum 26. The transferred toner image is transferred by discharging the transfer corotron 28. The recording paper onto which the toner image has been transferred is guided to the fixing device 42 by the vacuum transport device 41. The recording paper on which the fixing is completed is discharged onto the recording paper discharge tray 7 by the discharge roller 43.

The discharge roller 43 is composed of a pair of rollers having a concave and convex shape, and gives corrugation to the discharged recording paper by corrugation so that the discharged recording paper is aligned on the recording paper discharge tray 7. The clamshell 9 including the recording paper discharge tray 7 can be opened to a broken line position 9 'by operating a handle (not shown), thereby removing a paper jam and improving maintainability.

In this embodiment, when a recording sheet is jammed in a state of straddling between the paper transport paths 23 and 24, the roll paper feeding device 3 is forcibly pulled out and the remaining paper is removed. An appropriate door lock mechanism 90 is provided to physically prevent the roll paper feeder 3 from being pulled out in such a case so that the roll paper feeder 3 is not cut and scattered in the apparatus or damage is generated inside the apparatus. ing.

FIG. 4 is a cross-sectional view more specifically showing the configuration of the paper transport path in the roll paper feeder 3, and the same reference numerals as those described above denote the same or equivalent parts. Roll paper 11a, 11b of A3 size to A1 size can be mounted on the roll paper feeder 3, and each roll paper is fed by a feed roller 22a, 2
2b selectively feeds at a constant speed V (mm / sec). The feed rollers 22a and 22b also have a function of rewinding the roll paper remaining after the cutting operation in a direction opposite to the above-described paper feed direction.

Reflection type photo sensors 14a and 14b for detecting the width of the recording paper are provided downstream of the feed rollers 22a and 22b and in front of the junction 15, respectively. In the initialization operation, the roll paper 11a
The recording paper pulled out from (11b)
Photo sensor 14a (14b) by 2a (22b)
After the sheet is sent out to the detection position and the size is detected, when the leading end position reaches the merging portion 15 of the sheet conveying path, the apparatus enters a standby state.

A rotary cutter 25 is provided downstream of the junction 15. When the rotary cutter 25 receives the cut operation signal in response to the document length information,
The driving means (not shown) is urged to rotate the rotary blade 251, and the cutting edge 251 a is continuously rubbed with the fixed blade 252 to cut the recording paper into a predetermined length. Since the recording paper continues to be conveyed even during cutting by the rotary cutter 25, the rotary cutter 25 is mounted obliquely with respect to the paper conveyance direction so that the cut portion is perpendicular to the conveyance direction.

Downstream of the rotary cutter 25, there are provided a conveying roller 36 and a reflection type photo sensor 34 for detecting the leading end of the roll paper. The transport roller 36 is disposed to face the encoder wheel 38, and the encoder wheel 38 rotates following the running of the roll paper,
A pulse signal corresponding to the rotation amount is output from the encoder. This pulse signal is input to a control system (not shown) as a signal representing the roll paper transport amount after the leading edge of the recording paper reaches the photo sensor 34, so that the transport length of the recording paper can be recognized. ing. Note that the encoder wheel 38 is formed of a metal disk-shaped body so that the friction coefficient is maintained at a constant value regardless of the quality of the recording paper being conveyed.

The control system converts the received pulse signal into a transport length, and issues a cut operation signal to the driving device of the rotary cutter 25 when the transport length of the roll paper reaches a predetermined length. The photo sensor 34 is also used for detecting the leading edge of the roll paper, the paper jam at the trailing end of the roll paper after cutting, and the remaining roll paper other than during the paper feeding operation.

Below the roll paper loading section, fulcrums 44a,
The levers 45a and 45b that rotate about the roll 44b are arranged so as to be pressed against the outer peripheral surfaces of the roll paper 11a and 11b. The rotation angles of the fulcrums 44a and 44b are detected by a sensor (not shown), and when the distance δ between the outer diameter of the remaining roll paper and the outer diameter of the core 57 becomes 16 mm or less, a remaining amount insufficient signal is issued to the control system. Is displayed on the operation display section 8 to inform the operator that the remaining amount of recording paper has become low to urge the operator to prepare for replenishment.

FIG. 5 is a diagram specifically showing the configuration of the area surrounded by the broken line A in FIG. 3. FIG. 5A shows the state in which the upper baffle 50 provided on the paper transport path 24 is closed. FIG. 4B shows a state in which the upper baffle 50 is open.

The upper baffle 50 on the paper transport path 24 is generated on the recording paper when the registration roller 27 temporarily stops the leading edge of the paper in order to synchronize the toner image formed on the photosensitive drum 26 with the recording paper. The cam mechanism 54 is rotated when the leading edge of the sheet is detected by the registration sensor 52, and the upper baffle 50 is opened by rotating the lever 53 about the shaft 53a. It has become. At this time, the nip caused by the transport rollers 51a and 51b is also eliminated, so that the recording paper is in a free state. The deflection of the recording paper also serves to absorb the impact on the paper when the roll paper is cut by the rotary cutter 25 in the roll paper feeding device 3.

FIG. 6 is a view showing a configuration in which the roll paper core 57 is supported at both ends. The bearing member 46 provided coaxially with the central axis of the core 57 is sandwiched between the side surface of the groove and the L-shaped lever 49 in the groove provided in the roll paper support plate 47. In such a configuration, when the roll paper 11 ends and the core 57 is dragged by the roll paper, and the bearing member 46 moves up the slope of the groove against the holding force of the L-shaped lever 49, the L-shaped lever 49 rotates in the direction of the arrow around the rotation shaft 49a. When one end of the L-shaped lever 49 kicks the claw of the photointerrupter type sensor 50, a signal is output to the control system to notify the movement of the core 57.

Here, the operation when the roll paper ends during the paper feeding will be described. FIG. 7 is a block diagram showing a roll paper end determination method by the control system. As described above, if the winding thickness of the roll paper becomes thin during paper feeding and the distance δ (thickness of the roll paper) between the outer diameter of the remaining roll paper and the outer diameter of the core 57 becomes 16 mm or less, the control system is not controlled. Notification that the remaining amount of roll paper is insufficient. Thereafter, when the paper is further pulled out and the roll paper ends, the core 57 is dragged in the paper transport direction by the paper pulling force of the feed roller 22. As a result, as described with reference to FIG. 6, the bearing member 46 of the core 57 goes up the slope of the roll paper support plate 47, and the L-shaped lever 49 kicks the photo-interrupter type sensor 50 with the claw, so that the movement of the core 57 is stopped. The control system is notified.

In the control system, as shown in FIG. 7, the end of roll paper is determined only when both the remaining amount of roll paper and the movement of the core 57 are detected. Therefore, due to intermittent paper conveyance or the like, a force exceeding the holding force of the L-shaped lever 49 is applied to the core 57 and the roll paper main body moves in the paper feeding direction. Is not determined. Therefore, even if the movement of the main body of the roll paper in the paper feeding direction is erroneously detected, the end of the roll paper is not determined based on this.

FIGS. 9A and 9B are views showing the structure of the discharge roller 43 of the present invention. FIG. 9A is a front view, and FIG. 9B is a side view. In the present embodiment, as is clear from the comparison with the prior art described with reference to FIG. 8, the relative positional relationship between the sheet transport path 60 and the discharge roller 43 is changed, and the non-convex portion 431 b of the convex roller 431 is changed. The first nip point P1 between the first roller and the non-recess 432a of the concave roller 432 is
The relative position between the paper transport path 60 and the discharge roller 43 is defined so as to be formed on an extension plane of the inner upper surface (paper guide surface) of 0.

Therefore, according to the present embodiment, the corrugation depth H2 is equal to the corrugation depth H of the prior art.
1, the corrugation width W2 also matches the width of each roller, so that the corrugation size is reduced. Therefore, the corrugation does not reach the upstream side of the deflection point 61 of the recording paper 20, and the recording paper 20 is not damaged in a streak-like manner.

[0033]

As described above, according to the present invention, the depth and width of the corrugation are reduced and the corrugation can be reduced, so that the corrugation reaches the upstream side of the recording paper. This can prevent the occurrence of streak damage.

[Brief description of the drawings]

FIG. 1 is a perspective view of a large-sized printer device to which the present invention is applied.

FIG. 2 is a perspective view in a state where a roll paper feeding device is pulled out.

FIG. 3 is a side sectional view of FIG. 1;

FIG. 4 is a cross-sectional view of a roll paper feeding device.

FIG. 5 is a diagram specifically showing a configuration of a region surrounded by a broken line A in FIG. 3;

FIG. 6 is a diagram showing a configuration in which a core of roll paper is supported at both ends.

FIG. 7 is a block diagram showing functions of a control system.

FIG. 8 is a diagram showing a configuration of a conventional discharge roller.

FIG. 9 is a diagram illustrating a configuration of a discharge roller of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 3 ... Roll paper feeder, 4, 5 ... Cut paper feeder, 6 ... Manual feed part, 7 ... Recording paper discharge tray, 8 ... Operation display part, 11 ... Roll paper, 22 ... Sending roller, 25 ... Rotary cutter, 26 ... Photoconductor drum, 30 ... Cut paper, 43 ... Discharge roller, 57 ... Core, 60 ... Paper transport path, 431 ... Convex roller, 432 ...
Concave roller

Claims (1)

(57) [Claims] 1. An image forming apparatus for forming an image on a recording sheet and discharging the recording sheet from the discharge port to the outside of the apparatus, a sheet guide means for guiding the recording sheet after image formation to the discharge port, and provided near the discharge port; A discharge roller for discharging recording paper guided along the paper guide surface of the paper guide means to the outside, wherein the discharge roller is constituted by concave and convex rollers which engage with each other; The discharge roller has a first nip point formed by a concave portion and a non-convex portion of the convex roller, and a second nip point formed by a concave portion of the concave roller and a convex portion of the convex roller. An image forming apparatus characterized in that a point is positioned relative to a sheet guiding means such that a point is located on an extension plane of a sheet guiding surface of the sheet guiding means.