JP3752876B2 - Paper breakage detection mechanism and electrophotographic printer provided with paper breakage detection mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper breakage detection mechanism that suppresses the influence on paper runnability to a minimum and accurately detects corner breakage of a paper sheet and an electrophotographic printer including the paper breakage detection mechanism.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an electrophotographic printer has been provided with a paper break detection mechanism for detecting corner breaks of paper.
[0003]
For example, as disclosed in Japanese Patent Application Laid-Open No. 8-40600, sensors are arranged at both ends in the width direction of the target paper size, and the timing at which the paper passes over the sensor is detected, and the deviation of the timing is detected. Based on this, paper breakage is detected, or paper breakage is detected based on a difference in passing time passing over the sensor.
[0004]
[Problems to be solved by the invention]
In the paper breakage detection method described above, the sensor needs to be disposed on the conveyance path of the printer. Therefore, the sensor is detected by the paper heated by the fixing device or the like due to adverse effects on the paper conveyance, sensor misdetection due to paper dust, There were inconveniences such as cloudy surfaces.
[0005]
In addition, in the conventional method, since it is necessary to install sensors at both ends in the width direction of the paper, in order to cope with different paper sizes, it is necessary to arrange sensors for each size, and according to the size It was necessary to provide a large number of sensor holes on the conveying surface. As a result, the transportability of the paper may be deteriorated.
[0006]
The present invention has been made to solve the above inconveniences, and includes a paper breakage detection mechanism and a paper breakage detection mechanism for accurately detecting the corner breakage of the paper while minimizing the influence on the running property of the paper. An object is to provide an electrophotographic printer.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, the paper breakage detection mechanism according to claim 1 is a paper breakage detection mechanism for detecting a corner breakage of the paper, and is disposed on a straight line orthogonal to the paper transport direction. A plurality of stoppers for stopping the paper by contacting both ends of the paper, and detecting that the paper abutting the plurality of stoppers protrudes forward in the transport direction from the stopper. Paper breakage detecting means for detecting.
[0008]
The operation of the paper breakage detection mechanism according to claim 1 will be described.
[0009]
The conveyed paper comes into contact with the stopper and stops. At this time, if the sheet is bent, the bent portion comes into contact with the stopper, so that the leading end of the sheet on the side of the bent portion protrudes forward in the transport direction from the stopper. On the other hand, in the case of a sheet with no corner breakage, both ends of the leading edge of the sheet are in contact with the stopper, and the leading edge portion does not protrude forward in the transport direction with respect to the stopper. Therefore, by detecting that the leading edge portion of the paper protrudes forward in the transport direction from the stopper, the paper breakage detecting means can detect the angular breakage of the paper.
[0010]
The paper breakage detection mechanism is a paper breakage detection mechanism that detects a corner breakage of the paper, is disposed on a straight line orthogonal to the paper transport direction, and stops the paper by contacting both ends of the paper. There may be provided a plurality of stoppers and a paper break detecting means for detecting a timing at which the conveyed paper collides with each of the stoppers and detecting a corner break of the paper based on the timing difference .
[0011]
The operation of this paper breakage detection mechanism will be described.
[0012]
Both ends of the leading edge of the conveyed paper come into contact with the stopper. At this time, if the sheet is bent, the timing at which the bent part contacts the stopper is delayed. On the other hand, the leading edge of the sheet without corner breakage comes into contact with the stopper almost simultaneously. Therefore, it is possible to detect a corner break of the sheet based on a shift in timing at which the sheet contacts the both stoppers.
[0013]
The paper breakage detection mechanism is a paper breakage detection mechanism for detecting the corner breakage of the paper, and is disposed on a straight line orthogonal to the paper transport direction, and abuts at least three positions at both ends and the center of the paper. A plurality of stoppers for stopping the paper, and paper breakage detecting means for detecting the impact force that the conveyed paper collides with each stopper and detecting the corner breakage of the paper based on the difference in impact force of each stopper And may be provided .
[0014]
The operation of this paper breakage detection mechanism will be described.
[0015]
In the present invention, stoppers are provided that are arranged on a straight line perpendicular to the transport direction and come into contact with both ends and the center of the sheet. Therefore, if the conveyed paper is not bent at a corner, a substantially equivalent impact force acts on the stopper. However, when the paper is bent at a corner, the impact force acting on the stopper from the corner break portion is lower or zero compared to the impact force acting on the other stopper (the corner break portion is the stopper). Does not collide). Therefore, it is possible to detect paper breakage based on the difference in impact force.
[0016]
The paper breakage detection mechanism is a paper breakage detection mechanism that detects a corner breakage of the paper, and is disposed on a straight line orthogonal to the paper transport direction, and is a detection member that is displaced by contact between both ends of the paper. Further, a paper breakage detecting means may be provided which is disposed outside the detection member and includes a detection plate which detects a corner breakage of the paper by the contact of the detection member .
[0017]
The operation of this paper breakage detection mechanism will be described.
[0018]
When the paper comes into contact with the detection member, the detection member is displaced along the shape of the end of the paper (the direction of the force acting from the paper). That is, the detection member is displaced forward in the conveyance direction when the sheet is not bent, and when the sheet is bent, the detection member is displaced outward from the conveyance direction by the corner fold. Touch the plate. Therefore, when the detection plate detects the contact of the detection member, it is possible to accurately detect even a minute corner break of the paper.
[0019]
The paper breakage detection mechanism according to claim 2 is configured such that at least one of the paper breakage detection means and the stopper is displaceable in the paper width direction orthogonal to the transport direction. It is characterized by that.
[0020]
The operation of the paper breakage detection mechanism according to claim 2 will be described.
[0021]
Since the paper break detection means and stopper can be moved in the paper width direction according to the paper size, the paper break detection means or stoppers can be accurately folded to prevent corner breakage of different sizes of paper without disposing the paper break detection means or stopper for each paper size. It can be detected.
[0022]
An electrophotographic printer according to a third aspect is characterized in that the paper breakage detecting mechanism according to the first or second aspect is provided in a storage portion for storing printed paper.
[0023]
The operation of the electrophotographic printer according to claim 3 will be described.
[0024]
Since the paper breakage detection mechanism is provided in the storage unit that stores the printed paper last, it is possible to detect satisfactorily any corner breakage of the paper in any position of the transport path in the electrophotographic printer.
[0025]
The electrophotographic printer according to claim 4 is the electrophotographic printer according to claim 3, wherein the paper breakage detecting mechanism according to claim 1 or 2 temporarily stores the paper on which single-sided printing has been performed in the double-sided printing mode. It is characterized by being provided in.
[0026]
The operation of the electrophotographic printer according to claim 4 will be described.
[0027]
In the case of printing on both sides of the paper, after printing on one side, it is printed on the opposite side with the transport direction reversed. Therefore, when the paper breakage detection mechanism is provided only in the storage unit, it is possible to detect the corner breakage at the leading end of one of the sheets, but it is impossible to detect the corner breakage at the other end of the sheet. However, in the present invention, since the paper folding detection mechanism is also provided in the double-sided printing tray that temporarily stores the paper on which single-sided printing has been performed, the presence or absence of the corner folding is detected before the conveyance direction is reversed. It can detect with the said accommodating part. That is, in the double-sided printing mode in which the transport direction is reversed, it is possible to reliably detect the corner breakage of the paper at the front and rear ends in the transport direction.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
An electrophotographic printer provided with a paper breakage detection mechanism according to an embodiment of the present invention will be described below. The electrophotographic printer according to the present invention is characterized in that it has a paper breakage detection mechanism, so only the part where the paper breakage detection mechanism is provided will be described, and the description of the other parts will be omitted. To do.
[First Embodiment]
A paper breakage detection mechanism and an electrophotographic printer according to a first embodiment of the present invention will be described with reference to FIGS.
[0029]
As shown in FIG. 2, the paper breakage detection mechanism 10 of the present embodiment includes a storage tray (hereinafter referred to as a stacker) on which printed paper 16 conveyed by a guide 12 and a conveyance roller 14 in an electrophotographic printer is stacked. 18 is disposed inside.
[0030]
On the top surface 20 of the stacker 18, stoppers 22 are disposed at both end positions of the sheet on a straight line corresponding to the stop position of the sheet 16 and orthogonal to the transport direction (arrow X) (see FIG. 1A). Further, a line sensor 24 is disposed on the top surface 20 between the pair of stoppers 22.
[0031]
The paper breakage detection mechanism 10 according to the first embodiment configured as described above detects the corner breakage of the paper as follows.
[0032]
When a sheet 16 (hereinafter referred to as a sheet 16A) that has not been bent is transported to the stacker 18, both ends of the leading end 26 abut against the stopper 22, and the leading end 26 is in the transport direction (arrow X direction). Stop in an orthogonal state (see FIG. 1A). Therefore, the leading edge 26 of the paper 16A is not detected by the line sensor 24.
[0033]
On the other hand, when the paper 16 with the corner breakage (hereinafter referred to as the paper 16B) is conveyed, the tip end 26 of the sheet 16B is brought into contact with the stopper 22 by the corner bend portion 28 of the tip 26 abutting against the stopper 22. It protrudes forward in the transport direction from the straight line connecting the two. As a result, the leading edge 26 of the paper 16B is detected by the line sensor 24. That is, when the line sensor 24 detects the paper 16B (projection thereof), the corner break of the paper 16B can be detected.
[0034]
Note that the sheet 16B can be prevented from being stacked and used on the stacker 18 by stopping printing and warning the user based on the detection of the corner break of the sheet break detection mechanism 10.
[0035]
In the case of a high-speed printer in which the speed of the paper 16 entering the stacker 18 is very high, in order to prevent the paper 16 from rebounding, the stopper 22 can be displaced in the transport direction and a damper mechanism 30 is provided. It is conceivable that the stopper 22 is formed of a shock absorbing material such as rubber, or the stacker 18 is inclined to use the weight of the paper 16 (see FIG. 4).
[Second Embodiment]
Next, a paper breakage detection mechanism according to a second embodiment and an electrophotographic printer provided with the paper breakage detection mechanism will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0036]
As shown in FIGS. 5 and 6, in the paper breakage detection mechanism 40, the stopper 22 </ b> A and the line sensor 24 </ b> A can be moved in the width direction perpendicular to the transport direction by the drive mechanism 42. That is, the drive mechanism 42 moves the stopper 22A and the line sensor 24A in the width direction by transmitting the driving force of the motor 44 through the gear mechanism 46. On the other hand, the stopper 22B and the line sensor 24B are fixed to the top surface 20.
[0037]
The paper breakage detection mechanism 40 configured as described above detects the corner breakage of the paper 16 as follows.
[0038]
When the size of the paper set in the electrophotographic printer is detected, the motor 44 is driven to move the stopper 22A and the line sensor 24A to the end positions in the width direction corresponding to the paper size. As a result, the conveyed paper 16 comes into contact with the stoppers 22A and 22B at both ends of the leading end 26. Hereinafter, corner breakage can be detected in the same manner as in the first embodiment.
[0039]
As described above, the one set of stoppers 22A and 22B and the line sensors 24A and 24B can favorably detect the corner breaks of the sheets 16 of different sizes (for example, B4, A4, and B5 sizes).
[0040]
In this embodiment, only the stopper 22A and the line sensor 24A are moved. However, the stopper 22B and the line sensor 24B can also be moved.
[Third Embodiment]
An electrophotographic printer that prints on both sides prints the first side and then prints the second side with the paper transport direction opposite. Accordingly, there is a possibility that corner breaks that generally occur in front of the transport direction may occur before and after the transport direction of the paper. Therefore, there is a disadvantage that only one corner break before and after the sheet conveyance direction can be detected only by disposing the sheet break detection mechanisms 10 and 40 in the stacker 18 of the electrophotographic printer. In view of this, an electrophotographic printer that performs double-sided printing is proposed that reliably detects corner breaks in the front and rear directions of the paper.
[0041]
The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The feature of this embodiment is that the paper breakage detection mechanism 10 is not only in the stacker 18 of the electrophotographic printer, but also in the case of double-sided printing, a double-sided tray 50 for temporarily storing paper in order to reverse the conveyance direction after printing on the first side. It is also arranged inside.
[0042]
The sheet 16 on which the first surface stored in the double-sided tray 50 is printed by the guide 52 and the conveying roller 54 is stopped by the stopper 22 and then conveyed in the opposite direction by the driving roller 58 driven by the solenoid 56. The roller 60 and the guide 62 are used to print the second surface.
[0043]
At this time, the paper break detection mechanism 10 is provided in the double-sided tray 50, and detects a corner break at the leading end portion (hereinafter referred to as the first end portion) 16C in the transport direction in a state where the first surface is printed. Further, after reversing the transport direction, the corner break of the transport direction leading end (hereinafter referred to as the second end) 16D is detected by the corner break detection mechanism 10 disposed in the stacker 18 during the second surface printing. can do.
[0044]
As described above, in the electrophotographic printer according to the present embodiment, since the paper breakage detection mechanism 10 is provided in each of the double-sided tray 50 and the stacker 18, even in the double-sided printing mode in which the conveyance direction is reversed, the corner folding that can be formed at the front and rear ends in the conveyance direction. Can be reliably detected.
[0045]
Although the paper breakage detection mechanism 10 is provided in the present embodiment, the detection mechanism 40 may be provided.
[Fourth Embodiment]
Subsequently, a paper breakage detection mechanism according to a fourth embodiment and an electrophotographic printer including the mechanism will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0046]
The paper breakage detection mechanism according to the present embodiment incorporates an impact sensor that detects vibration when a paper collides with a stopper, instead of the line sensor of the paper breakage detection mechanism according to the first embodiment.
[0047]
That is, the paper breakage detection mechanism 70 incorporates an impact sensor 72 that detects an impact (vibration) when the paper 16 comes into contact with the stopper 22, and an output (vibration waveform) of each impact sensor 72 is detected by the detection circuit 74. To enter. The detection circuit 74 detects a corner break of the paper 16 depending on whether or not the difference t between the output timings of the impact sensors 72A and 72B is equal to or greater than a predetermined value.
[0048]
The operation of the paper breakage detection mechanism 70 configured as described above will be described.
[0049]
When the sheet 16A without corner breakage contacts the stoppers 22A and 22B, the timing of the impact (vibration) waveform detected by the impact sensor 72 of both the stoppers 22A and 22B is almost the same. Therefore, the difference in timing between the vibration waveforms (see FIG. 9B) of the impact sensors 72A and 72B input to the detection circuit 74 is less than a predetermined value, and it is determined that there is no corner break.
[0050]
On the other hand, when the paper 16B having the corner bent portion 28 comes into contact with the stoppers 22A and 22B, output waveforms of the impact sensors 72A and 72B input to the detection circuit 74 are as shown in FIG. In other words, the leading end 26 of the sheet 16B on the side where the corner is not bent comes into contact with the stopper 22B first, and the corner bent portion 28 comes into contact with the stopper 22A with a delay. As a result, the shift (difference) t between the output timings of the impact sensors 72A and 72B exceeds a predetermined value, and the detection circuit 74 determines that the corner is broken. In this case, the operation of the electrophotographic printer is stopped, and the user is notified by a display or a warning sound that corner breakage has occurred.
[0051]
As described above, in the paper breakage detection mechanism 70 according to the present embodiment, the impact sensor 72 is built in the stopper 22, and the corner breakage of the paper 16 can be detected based on the deviation of the output timing of the impact sensor 72.
[0052]
In addition, by using together with the line sensor 24 used in the paper breakage detection mechanism 10 of the first embodiment, the corner breakage of the paper 16 can be detected with higher accuracy.
[Fifth Embodiment]
Subsequently, a paper breakage detection mechanism 80 according to a fifth embodiment of the present invention will be described. The same components as those in the fourth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0053]
As shown in FIGS. 11A and 12A, the paper breakage detection mechanism 80 includes a stopper 22C having a built-in impact sensor 72C at the center of the sheet in addition to the stoppers 22A and 22B provided at both ends of the sheet. Prepare.
[0054]
The operation of the paper breakage detection mechanism 80 configured as described above will be described.
[0055]
When the paper 16A that is not bent is in contact with the stoppers 22A to 22C, the outputs of the impact sensors 72A to 72C that are input to the detection circuit 74 substantially coincide (see FIG. 11B).
[0056]
On the other hand, when the paper 16B having a corner fold contacts the stoppers 22B and 22C, the leading edge 26 of the paper 16B contacts two points (stoppers 22B and 22C), and therefore the corner fold portion 28 moves in the transport direction (arrow X). Direction) and does not contact the stopper 22A. As a result, the detection circuit 74 receives outputs only from the impact sensors 72B and 72C (see FIG. 12B). Therefore, in the detection circuit 74, when there is an input from one of the impact sensors 72A and 72B, when there is no input from the other impact sensor 72B and 72A, or there is an output difference between the impact sensors 72A and 72B and the impact sensor 72C. When the value exceeds a predetermined value, it is detected that the sheet 16 has been bent.
[Sixth Embodiment]
Next, a paper breakage detection mechanism according to a sixth embodiment of the present invention will be described. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0057]
As shown in FIGS. 13 and 14, the paper breakage detection mechanism 90 is tiltable suspended from the top surface 20 via a ball joint 92 at both end positions in the width direction orthogonal to the transport direction (arrow X direction). Type detection rod 94, a contact detection plate 96 that is disposed outside the detection rod 94 and detects the contact of the detection rod 94, and a corner break of the paper 16 is detected based on a detection signal of the contact detection plate 96. And a detection circuit 98. The detection rod 94 is configured to return to the original position by the spring 100.
[0058]
The operation of the paper breakage detection mechanism 90 configured as described above will be described.
[0059]
When the sheet 16A having no corner breakage is conveyed, both ends of the leading end 26 of the sheet 16A are in contact with the detection rods 94A and 94B, and the folding type detection rods 94A and 94B are tilted in the conveyance direction into the stacker 18. enter in. Therefore, the detection rods 94A and 94B do not come into contact with the contact detection plate 96, and it is confirmed that the paper 16A is not bent at a corner.
[0060]
On the other hand, when the paper 16B having a corner fold is conveyed, the leading end 26 (the side without the corner fold) of the paper 16B comes into contact with the detection rod 94A, and the detection rod 94A is tilted in the conveyance direction. However, when the corner bent portion 28 comes into contact with the detection rod 94B, the detection rod 94B is tilted in a direction inclined in the direction of the arrow Y from the conveyance direction to the sheet outer side. As a result, the detection rod 94B comes into contact with the contact detection plate 96, and the detection signal from the contact detection plate 96 is input to the detection circuit 98, whereby the corner break of the paper 16B is detected.
[0061]
As described above, in the paper folding detection mechanism 90 according to the present embodiment, the corner folding portion 28 of the paper 16 tilts the detection rod 94 outward and makes contact with the contact detection plate 96. It can be detected reliably.
[0062]
Note that the paper breakage detection mechanism 90 can be disposed not only on the stacker 18 but also on a double-sided tray 50 of an electrophotographic printer that performs double-sided printing.
[0063]
By the way, in the paper break detection mechanism of the fourth and fifth embodiments, it is possible to dispose a stopper or a sensor so as to be displaceable in accordance with the size of the paper as in the first embodiment.
[0064]
【The invention's effect】
The paper breakage detection mechanism according to the present invention can accurately detect the corner breakage of the paper. In addition, in the electrophotographic printer according to the present invention, the paper breakage detection mechanism is disposed in the storage portion for storing the printed paper, so that it is possible to satisfactorily detect the corner breakage occurring anywhere in the conveyance path. be able to. In addition, since no detection means is provided in the conveyance path, good traveling performance of the sheet is ensured. Furthermore, in an electrophotographic printer that performs double-sided printing, the paper breakage detection mechanism is also provided in a double-sided printing tray that temporarily stores paper that has already been printed on one side, so that the corners at the front and rear ends in the carrying direction that can be achieved in double-sided printing are provided. Breakage can be detected reliably.
[Brief description of the drawings]
FIGS. 1A and 1B are explanatory diagrams illustrating a detection state of a paper break detection mechanism according to a first embodiment of the present invention, in which FIG. 1A is a state in which a sheet without corner breakage is in contact with a stopper, and FIG. This is a state where a sheet of paper is in contact with the stopper.
FIG. 2 is a schematic explanatory diagram illustrating a paper breakage detection mechanism disposed in the electrophotographic printer according to the first embodiment of the present invention.
FIG. 3 is a schematic explanatory view showing a variation of the paper breakage detection mechanism according to the first embodiment of the present invention.
FIG. 4 is a schematic explanatory view showing a variation of the paper breakage detection mechanism according to the first embodiment of the present invention.
FIG. 5 is a schematic explanatory diagram of a paper breakage detection mechanism according to a second embodiment of the present invention.
FIG. 6 is an explanatory diagram of a movement state of a paper breakage detection mechanism according to a second embodiment of the present invention.
FIG. 7 is a schematic explanatory diagram of a paper breakage detection mechanism according to a third embodiment of the present invention.
FIG. 8 is a schematic explanatory diagram of a paper breakage detection mechanism according to a fourth embodiment of the present invention.
FIGS. 9A and 9B are diagrams illustrating a paper breakage detection mechanism according to a fourth embodiment of the present invention, in which FIG. 9A is an explanatory diagram of a state in which a sheet without corner breakage is in contact, and FIG. The output waveform is shown.
FIGS. 10A and 10B are diagrams for explaining a paper break detection mechanism according to a fourth embodiment of the present invention, in which FIG. The output waveform is shown.
FIGS. 11A and 11B are diagrams for explaining a paper break detection mechanism according to a fifth embodiment of the present invention, in which FIG. The output waveform is shown.
FIGS. 12A and 12B are diagrams for explaining a paper breakage detection mechanism according to a fifth embodiment of the present invention, in which FIG. The output waveform is shown.
FIG. 13 is a schematic explanatory diagram of a paper breakage detection mechanism according to a sixth embodiment of the present invention.
FIGS. 14A and 14B are diagrams for explaining a paper break detection mechanism according to a sixth embodiment of the present invention, in which FIG. 14A is a diagram illustrating a state in which a sheet without corner breakage is in contact, and FIG. FIG.
FIG. 15 is a schematic explanatory diagram of a paper breakage detection mechanism according to another example of the sixth embodiment of the present invention.
[Explanation of symbols]
10, 40, 70, 80, 90 Paper breakage detection mechanism 22 Stopper 24 Line sensor (paper breakage detection means)
72 Impact sensor (paper breakage detection means)
74 Detection circuit (paper breakage detection means)
94 Detection rod (detection member)
96 Contact detection plate (detection plate)

Claims (4)

A paper breakage detection mechanism for detecting corner breakage of paper,
A plurality of stoppers arranged on a straight line perpendicular to the paper transport direction and stopping the paper by contacting both ends of the paper;
A paper fold detection means for detecting a corner fold of the paper by detecting that the paper in contact with the plurality of stoppers protrudes forward in the transport direction from the stopper;
A paper breakage detection mechanism characterized by comprising: The paper breakage detecting means, Sukunakumo To one of claim 1, wherein the paper bending detection mechanism, characterized in that it is displaceably configured in the sheet width direction orthogonal to the conveying direction of the stopper. An electrophotographic printer, wherein the paper breakage detection mechanism according to claim 1 or 2 is provided in a storage portion for storing printed paper. 3. The electrophotographic printer according to claim 3, wherein the paper breakage detecting mechanism according to claim 1 or 2 is provided in a double-sided printing tray for temporarily storing a sheet on which single-sided printing has been performed in the double-sided printing mode.

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