JPH0777945B2 - Electrophotographic device paper feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device of an electrophotographic apparatus using roll paper as recording paper.

2. Description of the Related Art A conventional electrophotographic apparatus using roll paper for recording paper has a structure shown in FIG. In FIG. 8, 101 is a photosensitive drum, 102 is a charging unit, 103 is an exposing unit, 104 is a developing unit, 105 is a transferring unit, 106 is a separating unit, 107 is a fixing unit, 108 is a cleaning unit, and 109 and 111 are recording paper conveyances. Means, 110 is a cutter for cutting the recording paper, 112 is the recording paper, 11
2A is a recording paper roll. In the apparatus having this configuration, during rotation of the photosensitive drum 101, the charging unit 102, the exposure unit 103,
A toner image is formed on the photosensitive drum 101 by the developing unit 104. On the other hand, the recording paper 112 is conveyed from the recording paper roll 112A to the conveying means 1
It is fed out at 11, and is conveyed toward the photosensitive drum 101 by the conveying means 109. This recording paper is transferred onto the photosensitive drum 101 by the transfer means 1
The toner image is transferred at the image transfer position where 05 is located, the toner image is transferred, then separated from the photosensitive drum 101 by the separating unit 106, and fixed by the fixing unit 107. When a recording paper of one page length is supplied from the recording paper roll 112A during the transfer operation to the recording paper, the cutter 110 is operated by a recording paper cut signal (not shown), and the recording paper 112 is Cut to length. A recorded image can be obtained by repeating this.

Problems to be Solved by the Invention However, according to the electrophotographic apparatus having such a configuration, there is a problem that a linear image splatter occurs in the image formed on the recording paper in a direction perpendicular to the conveying direction of the recording paper. was there.

As a result of examining the cause of the above problem, the present inventor has found that this is caused by the operation of the cutter. That is, when the cutter cuts the recording paper, it strongly hits the recording paper. The impact at that time vibrates the recording paper, and it becomes a wave and is transmitted to the image transfer position. Here, the recording paper vibrates between the photosensitive drum and the transfer means, the static electricity of both is discharged,
The image was misaligned and the image was scattered.

The following two methods are conceivable as solutions to this problem. First of all, the recording paper is processed to hold a large amount of electric charge (usually a high resistance treatment) to strengthen the adhesive force between the photosensitive drum and the recording paper so that the recording paper does not vibrate due to the impact from the cutter. To However, in this case, the cost of the recording paper is high, that is, the running cost is high, and the advantage of the electrophotographic apparatus using plain paper is reduced. Further, under high humidity conditions, the above-mentioned decrease in electrostatic adhesion cannot be prevented, and it is not a sufficient countermeasure.

Secondly, the distance between the cutter and the transfer means is increased so that the leading edge of the recording paper has not yet reached the image transfer position during the cutter operation. However, in this case, the distance between the cutter and the image transfer position must be made longer than that of the longest recorded image, which causes a new problem of increasing the size of the apparatus.

The present invention has been made in view of the above-mentioned problems, and it is possible to eliminate the scattering of images during the operation of the cutter without incurring an increase in running cost and without increasing the size of the device. An object of the present invention is to provide a sheet feeding device of the apparatus.

Means for Solving the Problems In order to solve the above-mentioned problems, the present application discloses a cutting means for cutting a roll-shaped recording paper fed from the upper side, and a discharge of the recording paper cut by the cutting means. A roller provided on the side of the recording paper, which is longer than the width of the recording paper, and a guide which is in contact with the roller, which is located below, and which conveys the recording paper by the roller and the guide; And a transfer unit for transferring an image onto the recording sheet, and the roller of the conveying unit is arranged above and the guide is arranged below.

With the above-described structure, the present invention conveys the roll-shaped recording paper by the roller longer than the width of the recording paper and the guide in contact with this roller. The roll-shaped recording paper is wound around the guide, and the conveyance direction of the roll-shaped recording paper is regulated by the guide, and the roll-shaped recording paper is blocked from the cutting position by the guide and the roller when cutting. Therefore, vibration is not transmitted.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of an electrophotographic apparatus provided with a sheet feeding device according to the first embodiment of the present invention. In FIG. 1, 1 is a photosensitive drum, around which a charging means 2,
An exposing unit 3, a developing unit 4, a transferring unit 5, a separating unit 6, and a cleaning unit 8 are arranged, and a fixing unit 7 is provided downstream of the recording paper conveyance direction. This photosensitive drum 1
The paper feeding device for feeding the recording paper to the recording paper roll 10
And pull out the recording paper 11 from this recording paper roll 10,
A pair of conveying rollers 12 that conveys toward the photosensitive drum 1,
A cutter 13 for cutting the recording paper, a paper guide 14 formed of a flat plate for guiding the lower surface of the recording paper to an image transfer position,
Conveyor roller pressing recording paper 11 against paper guide 14
Have 15. The carrying roller 15 is in contact with the recording paper 11 over its entire width in the width direction perpendicular to the running direction.
The paper guide 14 which is composed of a stepless roller having a length longer than the width of the recording paper, and which is located below the roller,
It has a dimension longer than the width of the recording paper 11 so that it contacts the recording paper 11 over the entire width at least at a position facing the transport roller 15. This paper guide 14 and conveyance roller
Reference numeral 15 constitutes a vibration reflection means.

Next, the operation of the apparatus having the above configuration will be described. The photosensitive drum 1 rotates in the direction indicated by the arrow, and a toner image 17 is formed on the surface thereof. The conveying rollers 12 and 15 are also rotating in synchronization with the rotation of the photosensitive drum 1, so that the recording paper 11 is transferred to the recording paper roll 10
It is pulled out from and is transported to the image transfer position. Chart paper 11
Is brought into contact with the surface of the photosensitive drum 1 at the image transfer position, and the toner image 17 is transferred onto the recording paper by the transfer means 5. During this process, the cutter 13 is operated by a signal (not shown) indicating the end of the recording paper 12 to cut the recording paper 11. At this time, the recording paper 11 vibrates due to the shock of cutting, and its wave propagates to the left in FIG. However, recording paper 11
Is a vibration reflection means, that is, a paper guide 14 and a conveyance roller 15.
Since the whole width is pressed without a gap, the wave does not propagate from here to the left, but reflects and moves to the right,
Eventually the energy is released into the air. Therefore,
The impact of the cutter 13 is not transmitted to the transfer means 5. Strictly speaking, the transport roller 15 and the paper guide 14 slightly vibrate due to the above-mentioned waves. However, since the paper guide 14 is fixed to the apparatus main body (not shown) and the conveying roller 15 is pressed against the paper guide or vice versa, its amplitude is too small to be measured and can be ignored.

In the embodiment of FIG. 1, the paper guide 14 is at the bottom and the transport roller 15 is at the top, but the same effect can be obtained even if these are reversed. However, it is desirable to dispose the paper guide 14 on the lower side as shown in the drawing for another reason other than the purpose of the present invention to prevent the propagation of vibration.
The reason is briefly described below.

(1) The recording paper is easy to move along the curl.

(2) The recording paper easily moves downward due to its own gravity.

Considering the characteristics shown in (1) and (2), the curl of the recording paper is directed downward to align the directions that are easy to move.
The most stable running performance can be obtained by regulating the conveying direction with the paper guide.

FIG. 2 is a schematic configuration diagram of a sheet feeding device according to the second embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, a lever that supports the carrying roller 15 is connected to a spring 18 that acts in a direction to separate the carrying roller 15 from the paper guide 14, and a plunger 19 that presses the carrying roller 15 against the paper guide 14 during operation. . Transport roller 15 at the start of recording
Is separated from the recording paper 11 by the spring 18,
11 is conveyed to an image transfer position by a conveyance roller 12. First, the plunger 19 is actuated by the signal indicating the end of the recording paper, and the conveying roller 15 is pressed against the paper guide 14. The transport roller 15 continues to rotate at least thereafter by means not shown. Then, the transport roller 15
After the paper is pressed against the paper guide 14, the cutter 13 operates. After the trailing edge of the recording paper passes through the transport roller 15, the operation of the plunger 19 is completed and the transport roller 15 separates from the paper guide 14.

Also in this embodiment, the recording paper is fed by the transport roller during the cutter operation.
It is sandwiched between 15 and the paper guide 14, and the impact during the cutter operation is blocked, and the image transfer position is not reached, and good image transfer is performed. In this embodiment, the transport roller
There is a new effect that an increase in load due to friction between the paper 15 and the paper guide 14 can be suppressed.

FIG. 3 is a schematic configuration diagram of a paper feeding device according to a third embodiment of the present invention. In the present embodiment, a pair of transport rollers 15 and 20 having no step which can contact over the entire width of the recording paper 11 is arranged downstream of the cutter 13 so as to be pressed against each other.
One of the transport rollers 15 and 20 is rotated by means (not shown), and the other is rotated accordingly. Also in this embodiment, since the pair of transport rollers 15 and 20 sandwich the recording paper, the impact during the cutter operation is reflected by the transport rollers and is not transmitted to the image transfer position.
Note that reference numerals 21 and 22 denote paper guides, and the paper guides are arranged so as to cover the transport rollers in consideration that the recording paper easily moves along the transport rollers. This is for the purpose of stabilizing the running of the recording paper and does not restrict the present invention.

In the above-mentioned first to third embodiments, only one means for conveying the recording paper is provided between the cutter and the transfer means, but in addition to this, a conveying roller may be added.

FIG. 4 is a schematic configuration diagram of a paper feeding device according to a fourth embodiment of the present invention. In this embodiment, a pair of conveying rollers 25, a paper guide 26, a suction means 27 and the like are provided downstream of the cutter 13. The conveying roller 25 used here does not need to be a roller without a step like the one used in the above-mentioned embodiment, but is a roller with a step for nipping and conveying an appropriate position in the width direction of the recording paper. The attracting means 27 is capable of attracting and holding the recording paper, and an electrostatic attracting plate (for example, “Culon” (trade name) manufactured by Taihei Chemical Co., Ltd.) which is easily controlled electrically is used.

The operation will be described below. Photosensitive drum 1, transport roller
12, 25 are rotated in the direction of the arrow by means (not shown) to convey the recording paper to the transfer position. Conveyor rollers 12,2
The conveying speed by 5 is set higher than the peripheral speed of the photosensitive drum 1. In FIG. 5A, the recording paper 11 is fed in the direction of the photosensitive drum 1 by the conveying roller 25, and when the leading end of the recording paper 11 contacts the photosensitive drum 1, the recording paper is substantially horizontal as shown in FIG. However, when the leading edge of the recording paper comes into contact with the surface of the drum and starts to move together, the recording paper is bent between the photosensitive drum 1 and the transport roller 25 as shown in (b) due to the speed difference between the two. The deflection increases with time and comes into contact with almost the entire surface of the adsorption means 27 as shown in (c). In this manner, when the recording paper is in contact with the suction means 27, a signal (not shown) indicating the end of the recording paper is generated, and the suction means 27 is operated by the signal to suck the recording paper on the surface. . At this time, the recording paper does not slide horizontally by the suction means, but is relatively easily peeled off in the direction perpendicular to the suction surface (the direction indicated by the arrow X in FIG. 5B), and the recording paper contacts the surface of the photosensitive drum 1. As it is conveyed, the position is changed from the state (d) in FIG. 5B to the state (e).
In this way, the cutter 13 operates to cut the recording paper 11 while the recording paper 11 is being sucked by the suction means 27. At this time, the recording paper vibrates, passes through the conveyance roller 25, and reaches the suction means 27, but since the recording paper is sucked and held by the suction means 27, the vibration is reflected rightward here. , The image transfer position is never reached. Strictly speaking, the suction means slightly vibrates due to the vibration of the recording paper. However, since the suction means 27 is fixed to the main body of the apparatus and the total mass is extremely large, its amplitude is so small that it cannot be measured and can be ignored.

While the recording paper 11 is being sucked by the suction means 27, the suction means
Since the recording paper is accumulated between the 27 and the conveyance roller 25, the operation of the suction means is stopped after the operation of the cutter is completed. As a result, the recording paper 11 returns from the state (e) of FIG. 5B to the state shown in FIG. 5C. At this time, if the friction coefficient of the suction means is small, the recording paper may be rapidly restored and may become a new vibration source. On the other hand, the ON / OFF of the suction means is made in small increments (the cycle varies depending on the friction coefficient, the stiffness of the recording paper, etc.).
By switching to about 0.1 to 10 Hz), the recording paper can be slid gradually and the occurrence of vibration can be suppressed.

As described above, in this embodiment, the suction means constitutes the vibration reflection means, and the vibration during the cutter operation can be prevented from being transmitted to the transfer position. Here, the suction area of the suction means 27 required to reflect the vibration of the recording paper is
Although it is experimentally determined by the suction force per unit area of the suction means and cannot be unambiguously determined, it was practically applicable in the length range of 3 to 50 mm in the recording paper conveyance direction.

In the embodiment shown in FIGS. 4 and 5, the peripheral speed of the transport roller 25 is set to be higher than the peripheral speed of the photosensitive drum. The same effect can be obtained by adopting the two-speed switching method of increasing the speed. The transport roller 25 is not always necessary, but it is desirable to have the transport roller 25 for stability of traveling. Further, a conveying roller having a constant speed equal to the peripheral speed of the photosensitive drum may be provided between the suction means and the transfer means. By using such a conveying roller, the traveling of the recording paper is further stabilized.

Further, instead of fixing the suction means 27 to the apparatus main body, the suction means 27 may be moved in the same direction at substantially the same speed as the recording paper while being operated. In this case, the conveyance roller 25 and the photosensitive drum 1 are provided while having the vibration reflection effect of the recording paper by the suction means 27.
There is no need to bend the recording paper between and, and more stable recording paper running becomes possible.

In the above-described embodiment, the electrostatic attraction means is used as the attraction means 27, but the invention is not necessarily limited to this.
Any material can be used as long as it can control adsorption and release.

FIG. 6 is a schematic configuration diagram of a paper feeding device according to a fifth embodiment of the present invention. In this embodiment, instead of the suction means 27 in the embodiment of FIG. 4, an inclined flat plate-shaped paper guide 28 is used.
Is provided. As the paper guide 28, a material having a small friction coefficient with respect to the recording paper, for example, a metal plate, is used as in the normal paper guide. Also in this embodiment, the transport rollers 12 and 25 are driven at a higher speed than the peripheral speed of the photosensitive drum 1. When the leading edge of the recording paper 11 comes into contact with the photosensitive drum 1 and starts to move at the same speed as the peripheral speed of the photosensitive drum 1, the recording paper 11 is conveyed between the conveying roller 25 and the photosensitive drum 1 due to the speed difference with the conveying roller. 11 bends to be convex upward. Bent recording paper 11
Is pressed against the paper guide 28 by the force of the user's waist and does not move in the direction perpendicular to the recording paper surface. But,
Since the frictional force between the recording paper and the paper guide 28 is small, the recording paper slides smoothly in a direction horizontal to the recording paper surface, and the recording paper is smoothly conveyed to the image transfer position. A cutter (13) operates to cut the recording paper by a signal (not shown) indicating the end of the recording paper. At this time, the recording paper vibrates, and this wave propagates to the left in the recording paper, and reaches the paper guide 28 through a portion where the transport roller 25 is not in contact.
However, since the recording paper 11 is pressed against the paper guide 28 by the transport roller 25, the vibration is reflected at this portion, moves to the right, and eventually radiates the energy into the air. Therefore, the impact of the cutter is not transmitted to the image transfer position, and the disorder of the image is prevented. Strictly speaking, the paper guide 28 slightly vibrates entirely due to the above-mentioned waves, but since the paper guide 28 is fixed to the main body of the apparatus, its amplitude is too small to be measured and can be ignored.

As described above, in this embodiment, the paper guide 28 constitutes a vibration reflection means for reflecting the vibration. Here, the force of pressing the recording paper against the paper guide 28 is determined by the waist force determined by the density, thickness, etc. of the recording paper and the amount of bending. The greater this force, the more completely the wave can be reflected. In addition, paper guide
Since the wave reflected by 28 is reflected by the cut surface of the recording paper and advances toward the transfer position again, it is necessary to press the recording paper 11 against the paper guide 28 until the amplitude of the wave is attenuated. Therefore, the conveying roller 25 is necessary in the structure in order to press the cut recording paper against the paper guide 28.

In the above embodiment, the inclined paper guide 28 is provided above the horizontal paper guide 26, and the recording paper is bent and pressed against the paper guide 28, but the shape of the paper guides 26, 28 can be variously changed. Is. For example,
The upper paper guide 28 may be horizontal, the lower paper guide 26 may be inclined downward, and the recording paper may be pressed against the paper guide. Furthermore, it is also possible to press the bent recording paper against both paper guides. FIG. 7 shows an embodiment in that case, and a pair of curved paper guides 29 and 30 are provided between the conveying roller 25 and the photosensitive drum 1. In this embodiment, the recording paper 11 is fed by the conveying roller 25 at a speed higher than the peripheral speed of the photosensitive drum 1, the recording paper 11 is bent between the conveying roller 25 and the photosensitive drum 1, and both paper guides 29, 3 are conveyed.
The waist is pressed against the 0 parts 29A and 30A by the force of its own waist, and the vibration is reflected at these parts. Paper guide 2 in Figure 7
If 9,30 is used, the number of contact points between the recording paper and the paper guide will increase, so vibration reflection will occur even if the pressing force of each is set weakly, and as a result, there is an advantage that the recording paper can be stabilized against running. can get.

Although various examples of the vibration reflecting means for reflecting the vibration transmitted through the recording paper have been illustrated and described above, the vibration reflecting means is not limited to these examples, and the point is that the recording paper is placed in the direction perpendicular to the paper surface. The present invention is not limited to these examples, as long as it is fixed so as not to vibrate and has a function of reflecting waves.

EFFECTS OF THE INVENTION As is clear from the above description, according to the present invention, the roll-shaped recording paper is conveyed by the roller longer than the width of the recording paper and the guide in contact with the roller, and at this time, the roll-shaped recording paper is fed upward. Therefore, the roll-shaped recording paper with a curl hits the guide located below, and the guide direction of the roll-shaped recording paper is regulated by the guide, and at the time of cutting, the roll-shaped recording paper is cut by the guide and the roller. It is possible to cut off the vibration of time, and it is possible to combine the conveyance of the roll-shaped recording paper and the vibration of the cutting means at the time of cutting, and it is possible to realize with a simple configuration.

[Brief description of drawings]

1 is a schematic perspective view of an electrophotographic apparatus provided with a sheet feeding device according to a first embodiment of the present invention, and FIG. 2 is a schematic side view showing a sheet feeding device according to a second embodiment of the present invention. FIG. 3 is a schematic side view showing a paper feeding device according to a third embodiment of the present invention, and FIG.
FIG. 6 is a schematic side view showing a paper feeding device according to a fourth embodiment of the present invention, FIG. 5 is a side view of a main part for showing the operation of recording paper in the embodiment of FIG. 4, and FIG. FIG. 7 is a schematic configuration diagram showing a paper feeding device according to a fifth embodiment, and FIG.
FIG. 8 is a schematic configuration diagram showing a sheet feeding device according to the embodiment of the present invention, and FIG. 8 is a schematic configuration diagram of a conventional electrophotographic device. 1 ... Photosensitive drum, 5 ... Transfer means, 10 ... Recording paper roll, 11 ... Recording paper, 12 ... Conveying roller, 13 ... Cutter, 14 ... Paper guide, 15 ... Conveying roller, 17 ... …
Toner image, 20 ... Conveying roller, 25 ... Conveying roller, 27 ...
… Suction means, 26,28,29,30 …… Paper guide.

 ─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP-A-56-29257 (JP, A) JP-A-53-72280 (JP, A) JP-A-58-4394 (JP, A) JP-A-58- 22694 (JP, A) Actual development Sho 58-140094 (JP, U)

Claims (1)

[Claims] 1. A cutting means for cutting a roll-shaped recording paper fed from the upper side, and a roller provided on the discharge side of the recording paper cut by the cutting means and having a length longer than the width of the recording paper. Further, a guide that is in contact with the roller is located below, and a conveying unit that conveys the recording sheet by the roller and the guide, and a transfer unit that transfers an image onto the recording sheet conveyed by the conveying unit. A sheet feeding device for an electrophotographic apparatus, wherein a roller of a conveying unit is arranged above and a guide is arranged below.