JP2005231838A - Edge fold detection device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect edge fold of various recording mediums having different sizes using a small number of sensors. <P>SOLUTION: This edge fold detection device has a pair of jogger fences 42, 43 holding both side parts along the direction of conveyance of the recording medium S conveyed on a conveyance path and movable in the direction in which opposing intervals are changed in accordance with size of the recording medium S to be conveyed, a pair of first sensors 45a, 45b provided on the jogger fences 42, 43 to detect both side parts in the direction of lateral width of the recording medium S to be conveyed, a second sensor 46 deteting a center position in substantially central part in the direction of lateral width of the recording medium S to be conveyed, and a means for detecting whether edge fold occurs in the recording medium S or not based on the results of detection of the first sensors 45a, 45b and the second sensor 46. Consequently, edge fold of various recording mediums S having different sizes can be detected using the results of detection from three sensors 45a, 45b, and 46. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ear fold detection device that detects an ear fold of a recording medium conveyed in an image forming apparatus, and an image forming device including the ear fold detection device.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a recording medium fed from a paper feeding unit is transported on a transport path, and an image is formed on the recording medium in the transport process. In the case of an electrophotographic image forming apparatus, a fixing process of a toner image transferred onto a recording medium is performed in the conveyance process.

  In the process in which the recording medium is transported on the transport path, so-called ear folding, in which a corner portion of the recording medium in the transport direction, is bent may occur. Such a corner fold is likely to occur after the recording medium is curled by the fixing process.

  If the ear break occurs in the recording medium, it may cause a jam, or inconveniences such as an image not being formed at the ear break when double-sided printing is performed.

  As an invention that can detect such a bending of the recording medium, an invention is known in which a plurality of detection sensors are provided in a direction orthogonal to the conveyance direction of the recording medium (see, for example, Patent Document 1).

JP-A-6-183601

  In the invention described in Patent Document 1, in order to detect the ear folds of various types of recording media having different sizes (particularly, the size in the direction orthogonal to the conveyance direction), a large number of the recording media in the direction orthogonal to the conveyance direction of the recording medium. The number of sensors (for example, several or more) must be arranged, which increases the cost.

  In addition, it is difficult to determine whether the recording medium is skewed or whether the ear is broken.

  An object of the present invention is to detect an ear break of various recording media having different sizes using a small number of sensors.

  Another object of the present invention is to improve the detection accuracy of the broken ear.

  The ear fold detection device according to the first aspect of the invention holds both side portions along the transport direction of the recording medium transported on the transport path, and varies the facing distance according to the size of the transported recording medium. A pair of jogger fences movable in the direction, and a pair of first sensors that are provided on the jogger fence so as to be movable together with these jogger fences and detect both sides in the widthwise direction of the recording medium to be conveyed A second sensor for detecting a center position of a substantially central portion of the recording medium in a lateral width direction, and a means for detecting whether or not the recording medium is bent from a detection result of the first sensor and the second sensor. And having.

  Therefore, the recording medium transported on the transport path is held by the jogger fence on both sides in the width direction in the transport process, and enters the holding position or exits from the holding position. The front end portion of the recording medium entering the holding position can be detected by the three sensors, the first sensor and the second sensor. Based on the detection timings of these three sensors, it is possible to detect whether or not the recording medium is broken. The broken ears that can be detected in this way are the broken ears on one side and the broken ears on both sides.

  The pair of jogger fences can move in a direction in which the facing distance varies according to the size of the recording medium conveyed on the conveyance path, and the pair of first sensors provided on the jogger fence moves together with the jogger fence. Therefore, even when various types of recording media having different sizes are transported, it is only necessary to provide three sensors for detecting the ear folds of the recording media, and various types having different sizes using a small number of sensors. Can be detected.

  According to a second aspect of the present invention, in the ear fold detection device according to the first aspect, the pair of the first sensor and the second sensor are arranged on a straight line in a direction perpendicular to the conveyance direction of the recording medium. .

  Therefore, it is possible to detect whether or not the recording medium is broken by simply comparing the timings of the outputs from the three sensors, and the configuration for detecting the broken ear can be simplified.

  According to a third aspect of the present invention, in the ear fold detection device according to the first aspect, the second sensor is disposed at a position where the recording medium enters and exits a holding position by the jogger fence.

  Therefore, the second sensor can also be used as a sensor for detecting a jam of the recording medium conveyed on the conveying path, and the number of dedicated parts for detecting the ear breakage of the recording medium is reduced to simplify the structure. Can be achieved.

  According to a fourth aspect of the present invention, in the ear fold detection device according to any one of the first to third aspects, the detection of whether or not the ear fold has occurred is performed in a process in which the recording medium enters the holding position by the jogger fence. This is performed based on detection results of the first sensor and the second sensor.

  Therefore, it is possible to detect the ear break of the recording medium in the process of entering the holding position by the jogger fence. For this reason, after the recording medium is held by the jogger fence, when the recording medium is sent out from the holding position by the jogger fence, the recording medium can be discharged to the discharge tray.

  According to a fifth aspect of the present invention, in the ear fold detection device according to any one of the first to third aspects, the detection as to whether or not an ear fold has occurred is made by detecting the jogger fence after the recording medium is jogged by the jogger fence. This is performed based on the detection results of the first sensor and the second sensor in the process of exiting from the holding position.

  Therefore, since the detection of the folding of the recording medium is performed after the jogger process using the jogger fence, the erroneous detection of the folding of the ear caused by the skew of the recording medium can be prevented, and the accuracy of the detection of the folding of the ear is increased.

  According to a sixth aspect of the present invention, in the ear fold detection device according to any one of the first to fifth aspects, at least one of the first sensor and the second sensor is a reflective sensor.

  Therefore, a reflective sensor can be used as the first sensor and the second sensor for detecting broken ears.

  According to a seventh aspect of the present invention, in the ear fold detection device according to any one of the first to fifth aspects, at least one of the first sensor and the second sensor is a transmissive sensor.

  Therefore, a transmissive sensor can be used as the first sensor and the second sensor for detecting broken ears.

  According to an eighth aspect of the present invention, in the ear fold detection device according to the sixth aspect, the reflective sensor is disposed at a position where the recording medium is detected from the lower side of the recording medium.

  Since the recording medium moves downward due to its own weight, the distance between the reflection type sensor and the recording medium conveyed above the reflection type sensor is maintained constant, and the accuracy of detection of the broken ear is increased.

  According to a ninth aspect of the present invention, in the ear fold detection device according to the eighth aspect, the reflective sensor is covered with a light transmissive member.

  Therefore, dust such as paper dust is prevented from adhering to the reflective sensor, and the detection accuracy of the reflective sensor is maintained.

  According to a tenth aspect of the present invention, in the ear fold detection device according to the ninth aspect, the surface of the light transmissive member and the conveyance surface on which the recording medium is conveyed are located in the same plane.

  Therefore, the transported recording medium does not interfere with the light transmissive member, and the transport is smoothly performed when the recording medium is transported above the reflective sensor.

  According to an eleventh aspect of the present invention, in the ear fold detection device according to the sixth aspect, the reflective sensor is arranged at a position where the recording medium is detected from above the recording medium.

  Therefore, dust such as paper dust is prevented from adhering to the reflective sensor, and the detection accuracy of the reflective sensor is maintained.

  According to a twelfth aspect of the present invention, in the ear fold detection device according to the eleventh aspect, the reflective sensor is covered with a light transmissive member.

  Accordingly, dust such as paper dust is further prevented from adhering to the reflective sensor, and the detection accuracy of the reflective sensor is maintained.

  According to a thirteenth aspect of the present invention, in the ear fold detection device according to the seventh aspect, either one of the light emitting unit and the light receiving unit constituting the transmissive sensor is located below the recording medium to be conveyed, The light emitting part or the light receiving part located below the recording medium to be recorded is covered with a light transmissive member.

  Therefore, dust such as paper dust is prevented from adhering to the light emitting unit or the light receiving unit located on the lower side of the conveyed recording medium, and the detection accuracy of the transmission type sensor is maintained.

  According to a fourteenth aspect of the present invention, in the ear fold detection device according to the thirteenth aspect, the surface of the light transmissive member and the conveyance surface on which the recording medium is conveyed are located in the same plane.

  Therefore, the transported recording medium does not interfere with the light transmissive member, and the transport is smoothly performed when the recording medium is transported above the reflective sensor.

  According to a fifteenth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to fourteenth aspects, and a printer that forms an image in accordance with image data input to a conveyed recording medium. An engine.

  Therefore, by forming an image only on a recording medium in which no ear breakage has occurred based on the detection result of the ear break detection device, it is possible to realize a high-quality image formation.

  According to a sixteenth aspect of the present invention, in the image forming apparatus according to the fifteenth aspect, the image forming apparatus includes a fixing device, and the ear fold detection device is provided on the downstream side of the fixing device along the conveyance direction of the recording medium.

  Accordingly, the corner break of the recording medium is likely to occur during the fixing process in the fixing device, and the ear break detection of the recording medium is efficiently performed by providing the ear break detection device on the downstream side of the fixing device along the conveyance direction of the recording medium. Can do well.

  According to the ear break detection device of the first aspect of the invention, it is possible to detect the ear breaks of various types of recording media having different sizes using the three sensors of the pair of first sensor and second sensor.

  According to the ear break detection device of the invention described in claim 2, it is possible to detect whether or not an ear break has occurred in the recording medium simply by comparing the timings of the outputs from the three sensors. The configuration for detection can be simplified.

  According to the third aspect of the invention, the second sensor can be used as a sensor for detecting a jam of the recording medium conveyed on the conveying path, and for detecting the broken ear of the recording medium. The number of dedicated parts can be reduced and the structure can be simplified.

  According to the fourth aspect of the present invention, it is possible to detect the folding of the recording medium while the recording medium enters the holding position by the jogger fence.

  According to the jam detecting device of the fifth aspect of the invention, since the detection of the folding of the recording medium is performed after the jogger processing using the jogger fence, it is possible to prevent erroneous detection of the folding of the ears caused by the skew of the recording medium. The accuracy of detection of broken ears can be increased.

  According to the ear break detection device of the invention described in claim 6, a reflection type sensor can be used as the first sensor and the second sensor for ear break detection.

  According to the ear break detection device of the seventh aspect of the invention, a transmission type sensor can be used as the first sensor and the second sensor for ear break detection.

  According to the ear break detection device of the invention described in claim 8, since the distance between the reflection type sensor and the recording medium conveyed above the reflection type sensor is kept constant, the accuracy of the ear break detection is improved. Can do.

  According to the ear break detection device of the ninth aspect of the invention, it is possible to prevent the dust such as paper dust from adhering to the reflection type sensor, and to maintain the detection accuracy of the reflection type sensor.

  According to the ear fold detection device of the tenth aspect of the present invention, it is possible to prevent the recording medium being conveyed from interfering with the light transmissive member, and smooth conveyance when the recording medium is conveyed above the reflective sensor. Can be done.

  According to the ear fold detection device of the invention of the eleventh aspect, it is possible to prevent adhesion of dust such as paper dust to the reflection type sensor, and to maintain the detection accuracy of the reflection type sensor.

  According to the ear break detection device of the twelfth aspect of the present invention, it is possible to further prevent the dust such as paper dust from adhering to the reflection type sensor and maintain the detection accuracy of the reflection type sensor.

  According to the ear break detection device of the thirteenth aspect of the present invention, it is possible to prevent adhesion of dust such as paper dust to the light emitting unit or the light receiving unit located below the conveyed recording medium, and the detection accuracy of the transmission type sensor. Can be maintained.

  According to the ear fold detection device of the fourteenth aspect of the invention, it is possible to prevent the recording medium being conveyed from interfering with the light transmissive member, and smooth conveyance when the recording medium is conveyed over the reflective sensor. Can be done.

  According to the image forming apparatus of the fifteenth aspect of the present invention, since the ear fold detection device according to any one of the first to fourteenth aspects is provided, the ear fold is not generated based on the detection result of the ear fold detection device. Image formation can be performed only on the recording medium, and high-quality image formation can be realized.

  According to the image forming apparatus of the sixteenth aspect of the invention, since the folding of the recording medium is likely to occur during the fixing process in the fixing device, the folding of the ear is detected downstream of the fixing device along the conveyance direction of the recording medium. By providing this, it is possible to efficiently detect the folding of the recording medium.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic front view showing an internal structure of a tandem type color copying machine 1 which is an image forming apparatus provided with the ear break detection device of the present invention.

  The color copying machine 1 houses a printer engine 3, an intermediate transfer belt 4, a fixing device 5, a reversing unit 6 and the like in the upper part of the apparatus main body 2. A paper feed cassette 7 on which the recording medium S is loaded is detachably attached to the lower part in the apparatus main body 2. On the upper part of the apparatus main body 2, an ADF 8 that automatically feeds a document to be read, a contact glass 9 on which the document to be read is placed, and a document automatically fed by the ADF 8 or placed on the contact glass 9. An image reading device 10 for reading a document is disposed.

  In the apparatus main body 2, the recording medium S fed from the paper feed cassette 7 passes through the printer engine 3 and the fixing device 5 to the paper discharge tray 11, and the recording medium S is transported in the transport path 12. The conveyance path 13 branched at a position downstream of the fixing device 5 along the direction and directed to the reversing unit 6, and the recording medium S reversed in the reversing unit 6 is a printer along the conveyance direction of the recording medium S in the conveyance path 12. A conveyance path 14 that is conveyed upstream of the engine 3 is formed. On the conveyance path 12, a conveyance roller 15, a registration roller 16, a transfer roller 17, a conveyance belt 18, and the like are arranged.

  The printer engine 3 includes four drum-shaped photoconductors 19 that are spaced apart at equal intervals and arranged in parallel in the horizontal direction, a motor (not shown) that drives the photoconductors 19 to rotate around the center line, A charging roller 20 that uniformly charges the outer peripheral surface, an optical writing device 21 that writes an electrostatic latent image by exposing the outer peripheral surface of each photoconductor 19 charged by the charging roller 20 according to image data, A developing device 22 that visualizes the electrostatic latent image as a toner image by supplying toner to the latent image, and a cleaning that cleans the toner remaining on the photoreceptor 19 after the toner image is transferred onto the intermediate transfer belt 4. It is comprised by the apparatus 23 grade | etc.,. In order to transfer the toner image on the photoconductor 19 onto the intermediate transfer belt 4, a transfer roller 24 disposed opposite the photoconductor 19 so as to sandwich the intermediate transfer belt 4 is used. The toners housed in the developing devices 22 arranged around the four photoconductors 19 have different colors, and therefore, toner images (Y; Yellow, M; magenta, C; cyan, B; black). By sequentially transferring these different color toner images onto the intermediate transfer belt 4, a color toner image is formed on the intermediate transfer belt 4, and this color toner image is transferred onto the recording medium S.

  The image reading device 10 includes first and second traveling bodies 25 and 26 that can travel at a speed of 2: 1 in parallel with the contact glass 9, a lens 27, a CCD 28, and the like. The first traveling body 25 includes a light source 29 for illuminating the original surface of the original document conveyed by the ADF 8 or the original document placed on the contact glass 9, and is reflected by the original surface along the reading optical axis. And a first mirror 30 that reflects the reading light that travels in this manner. The second traveling body 26 is mounted with a second mirror 31 and a third mirror 32 that further reflect the light reflected by the first mirror 30. A lens 27 and a CCD 28 are arranged in front of the reading light sequentially reflected by the first to third mirrors 30, 31, and 32 in the traveling direction.

  In such a configuration, in the color copying machine 1, an original is set on the ADF 8, or the original is placed on the contact glass 9, and a start key provided on an operation panel (not shown) is pressed. Then, the image reading device 10 reads the image of the document, and image formation by the printer engine 3 is started according to the reading result. In the image formation by the printer engine 3, image data is created based on the reading result of the image reading device 10, light is emitted from the optical writing device 21 according to the image data, and the photoconductor is generated by the emitted light. 19 surfaces are exposed and scanned. By this exposure scanning, an electrostatic latent image is formed on the surface of the photoconductor 19, and this electrostatic latent image is visualized as a toner image by the toner supplied from the developing device 22. The toner image formed on each photoconductor 19 is transferred onto the intermediate transfer belt 4 that rotates in synchronization with the photoconductor 19, and a color toner image is formed on the intermediate transfer belt 4.

  On the other hand, when the start key is pressed, the recording medium S of the designated size or the recording medium S of the size automatically selected according to the document size or the like is separated and fed from the inside of the paper feed cassette 7, and the conveyance path 12 is conveyed toward the printer engine 3. The recording medium S conveyed on the conveyance path 12 is sent to the transfer position by the transfer roller 17 in accordance with the timing of the image forming operation in the printer engine 3, and the color toner image on the intermediate transfer belt 4 is recorded on the recording medium S. Is transcribed. The recording medium S to which the toner image has been transferred is conveyed to the fixing device 5 by the conveying belt 18, and is subjected to fixing processing by applying heat and pressure in the fixing device 5.

  The recording medium S on which the toner image is fixed after the fixing process is completed is discharged onto the discharge tray 11 as it is, or is sent to the conveyance path 13 toward the reversing unit 6 for double-side printing. Switching between whether the recording medium S that has passed through the fixing device 5 is discharged onto the discharge tray 11 or sent into the transport path 13 is performed by switching the rotation of the switching claw 33. The recording medium S transported on the transport path 13 and sent to the reversing unit 6 is reversed in the traveling direction in the reversing unit 6, and after the traveling direction is reversed, the recording medium S is joined on the transport path 14 with the transport path 12. It is conveyed toward. The recording medium S sent from the conveyance path 14 to the conveyance path 12 is reversed so that the back surface on which the toner image is not formed faces the photoconductor 19. Image formation by the engine 3 is performed. The recording medium S having the toner image transferred on the back surface is subjected to a fixing process again by the fixing device 5 and then discharged onto the discharge tray 11.

  Under such a configuration, characteristic portions of the present embodiment will be described in order. As shown in FIGS. 2 to 4, the reversing unit 6 detects a paper jam of the bottom plate 41, a pair of jogger fences 42 and 43 located on both sides of the bottom plate 41, and the recording medium S conveyed through the conveyance path 13. A jam sensor 44, a pair of first sensors 45a and 45b for detecting an ear break of the recording medium S, a second sensor 46 for detecting an ear break of the recording medium S, a switching claw 48, and the like. Yes.

  The jogger fence 42 is formed in a U-shaped cross section having a lower piece portion 42a and an upper piece portion 42b. The jogger fence 43 has the same shape as the jogger fence 42 and is formed in a U-shaped cross-sectional shape having a lower piece portion 43a and an upper piece portion 43b. The jogger fences 42 and 43 are arranged so that the U-shaped opening portions are opposed to each other, and both sides along the transport direction of the recording medium S transported on the transport path 13 are held by the U-shaped opening portions. It is positioned as follows. The surfaces of the lower pieces 42a and 43a and the surface of the bottom plate 41 are positioned so as to be the same surface, and these surfaces serve as the conveyance surface of the recording medium S fed between the jogger fences 42 and 43.

  Racks 49 a and 49 b disposed below the bottom plate 41 are connected to the jogger fences 42 and 43, and the racks 49 a and 49 b mesh with the pinion 50. By these racks 49a, 49b and the pinion 50, the pair of jogger fences 42, 43 can be moved by the same size in the direction of contacting and separating from each other. In one rack 49b, a drive mechanism for performing jogger processing for moving the jogger fences 42, 43 in the approaching / separating direction according to the size (width size) of the recording medium S to be conveyed and reciprocating with a short stroke. (Not shown) are connected.

  The first sensor 45 a is housed in a notch hole 51 formed in the lower piece portion 42 a of the jogger fence 42, and the upper portion of the first sensor 45 a in the notch hole 51 is covered with a light transmissive member 52. The surface of the light transmissive member 52 and the surface of the lower piece portion 42a are the same surface. Similarly, the first sensor 45 b is housed in a notch hole 51 formed in the lower piece 43 a of the jogger fence 43, and the upper part of the first sensor 45 b in the notch hole 51 is covered with a light transmissive member 52. The surface of the light transmissive member 52 and the surface of the lower piece 43a are the same surface.

  The second sensor 46 is housed in a notch hole 53 formed in the bottom plate 41, and the upper part of the second sensor 46 in the notch hole 53 is covered with a light transmissive member 54. The surface of the light transmissive member 54 and the surface of the bottom plate 41 are the same surface.

  The first sensors 45a and 45b and the second sensor 46 are both reflective sensors, and a light emitting portion and a light receiving portion are disposed adjacent to each other. By receiving the light emitted from the light emitting unit and reflected by the detection target (here, the recording medium S) by the light receiving unit, the presence of the detection target can be detected.

  The second sensor 46 is disposed at a substantially intermediate position between the pair of jogger fences 42 and 43. The second sensor 46 and the pair of first sensors 45 a and 45 b are arranged on a straight line in a direction perpendicular to the conveyance direction of the recording medium S held on both sides by the jogger fences 42 and 43.

  FIG. 5 is a block diagram showing an electrical connection of each part provided in the color copying machine 1 of the present embodiment. The color copying machine of the present embodiment is provided with a main control unit 55 having a microcomputer configuration, and this main control unit 55 drives and controls each unit. The main control unit 55 includes a ROM (Read Only Memory) 58 that stores in advance fixed data such as a program via a bus line 57 in a CPU (Central Processing Unit) 56 that executes various calculations and drive control of each unit. A RAM (Random Access Memory) 59 functioning as a work area for storing data in a rewritable manner is connected. The main engine 55 is connected to the printer engine 3, the ADF 8, the image reading device 10, the jam sensor 44, the first sensors 45a and 45b, the second sensor 46, and the like.

  In the color copying machine 1 of the present embodiment, when the detection result from the pair of first sensors 45a and 45b and the detection result of the second sensor 46 are input to the main control unit 55, the jogger fence is based on the detection result. It is detected whether or not the recording medium S sent to the holding position by 42 and 43 has been folded. As a result, a function as means for detecting whether or not the recording medium S is broken is executed.

  FIG. 6 shows a case where an ear fold (ear fold width dimension X) occurs at one end of the recording medium S passing through the fixing device 5 and being conveyed on the conveyance path 13 in the conveyance direction. . When the recording medium S in which the ear breakage has occurred on one end side is conveyed in the direction of arrow A toward the holding position by the jogger fences 42, 43, in the conveyance process, as shown in FIG. 45b and the second sensor 46 are turned on at the same timing, but the timing at which the first sensor 45a is turned on is delayed by a time T. Assuming that the conveyance speed of the recording medium S is V, X = V × T, and it is possible to detect the occurrence of an edge fold having a width dimension of X on one end side (jogger fence 42 side) of the recording medium S. .

  In FIG. 7, the ear folds (ear fold width dimensions X and Y, where X <Y) occur at both ends of the recording medium S passing through the fixing device 5 on the transport path 13 in the transport direction. It shows the case. When the recording medium S in which the ear folds are generated is conveyed toward the holding position by the jogger fences 42 and 43, in the conveyance process, as shown in FIG. It is turned on, and then turned on in the order of the first sensor 45a and the first sensor 45b. The timing at which the first sensors 45a and 45b are turned on differs according to the width dimensions X and Y of the ear fold, the timing at which the first sensor 45a is turned on is delayed by time T, and the timing at which the first sensor 45b is turned on is time. Delayed by T1. Assuming that the conveyance speed of the recording medium S is V, X = V × T and Y = V × T1, and an edge fold with a width dimension of X occurs on one end side (jogger fence 42 side) of the recording medium S. It is possible to detect that an ear break having a width dimension of Y has occurred on the other end side of S (the jogger fence 43 side).

  Based on the detection result of the edge break, the image formation on the back surface in the process of transporting the recording medium S on which the ear break has occurred on the transport path 12 is stopped, or the transport path 13 is reversely fed. Thus, it is possible to execute processing such as discharging onto the discharge tray 11.

  Here, the pair of jogger fences 42, 43 can move in a direction in which the facing distance varies depending on the size of the recording medium S conveyed on the conveyance paths 12, 13, 14. The pair of first sensors 45 a and 45 b provided on the side move together with the jogger fences 42 and 43. For this reason, even when various types of recording media S of different sizes are transported, only three sensors 45a, 45b, 46 need to be provided to detect the ear breaks of those recording media S, and a small number The sensors 45a, 45b, and 46 can detect the folding of various recording media S having different sizes.

  In the ear break detection device of the present embodiment, the pair of first sensors 45a and 45b and the second sensor 46 are arranged on a straight line in a direction orthogonal to the conveyance direction of the recording medium S. , 45b, and 46, it is possible to detect whether or not the recording medium S is broken by simply comparing the output timings, and the configuration for detecting the broken ear can be simplified.

  Since the pair of first sensors 45a and 45b and the second sensor 46, which are reflective sensors, are disposed at positions where the recording medium S is detected from the lower side of the recording medium S, the transported recording medium S has its own weight. Therefore, the distance between the sensors 45a, 45b, 46 and the recording medium S conveyed above the sensors 45a, 45b, 46 is kept constant, and the accuracy of detecting the ear breakage is increased.

  These sensors 45a, 45b, and 46 are covered with the light transmissive members 52 and 54, so that the adhesion of dust such as paper dust is prevented, and the detection accuracy is not lowered due to the adhesion of dust. Is maintained.

  Further, the surfaces of the light transmissive members 52 and 54 and the surfaces of the lower pieces 42a and 43a, which are transport surfaces on which the recording medium S is transported, are flush with each other, and the surface of the light transmissive member 54 and the bottom plate 41 are provided. Since the recording medium S to be conveyed does not interfere with the light transmissive members 52 and 54, the recording medium S is conveyed above the sensors 45a, 45b, and 46. Is done smoothly.

  A second embodiment of the present invention will be described with reference to FIG. The same portions as those described in FIGS. 1 to 7 are denoted by the same reference numerals, and description thereof is omitted (the same applies to the following embodiments).

  The external structure of the present embodiment is the same as that of the first embodiment, and the difference is the timing of detection of broken ears by the sensors 45a, 45b, and 46. In the present embodiment, detection by the sensors 45a, 45b, and 46 is performed in the process in which the recording medium S exits the holding position by the jogger fences 42 and 43.

  As shown in FIG. 8A, in the process in which the recording medium S located at the holding position by the jogger fences 42 and 43 exits from the holding position in the direction of arrow B, the ear breakage of the recording medium S is detected. .

  When the recording medium S in which the edge fold (ear fold width dimension X) is generated at one end is stopped at the holding position by the jogger fences 42, 43, the outputs of the three sensors 45a, 45b, 46 are turned on. It has become. When the recording medium S is conveyed in the direction of arrow B, the first sensor 45a is turned off first, and then the first sensor 45b and the second sensor 46 are turned off at a timing delayed by T time. Assuming that the conveyance speed of the recording medium S is V, X = V × T, and it is detected that an edge break having a width dimension of X has occurred on one end side (jogger fence 42 side) of the recording medium S. it can.

  Therefore, even when the recording medium S is transported to the holding position by the jogger fences 42 and 43 in a state where the recording medium S is skewed, the recording medium S is detected after the jogger processing by the jogger fences 42 and 43 is performed. Since the broken ear detection is performed after the skew state is resolved by the jogger process, it is possible to prevent the erroneous detection of the broken ear caused by the skew and improve the accuracy of the broken ear detection.

  Next, a third embodiment of the present invention will be described with reference to FIG. The basic structure of the present embodiment is the same as that of the first embodiment, and this embodiment is different from the first embodiment in that the second sensor 46 described in the first embodiment is used. The jam sensor 44, which is omitted and is disposed at a position where the recording medium S enters and exits the holding position by the jogger fences 42 and 43, is also used as a second sensor for detecting a broken ear. The jam sensor 44 is a reflective sensor.

  As shown in FIG. 9A, in the process in which the recording medium S located at the holding position by the jogger fences 42 and 43 exits from the holding position in the direction of arrow B, the ear breakage of the recording medium S is detected. .

  When the recording medium S in which the ear fold (ear fold width dimension X) is generated at one end is stopped at the holding position by the jogger fences 42 and 43, the outputs of the first sensors 45a and 45b are on. The jam sensor (second sensor) 44 is off. When the recording medium S is conveyed in the direction of arrow B, the jam sensor (second sensor) 44 is turned on, the first sensor 45a is turned off, and then the first sensor 45b is delayed by T time. Turns off. Assuming that the conveyance speed of the recording medium S is V, X = V × T, and it is possible to detect the occurrence of an edge break having a width dimension of X on one end side (jogger fence 42 side) of the recording medium S. .

  According to the present embodiment, since the jam sensor 44 is also used as the second sensor, the number of dedicated parts for detecting the ear breakage of the recording medium S can be reduced, the structure is simplified, and the cost is reduced. Can be achieved.

  A fourth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the first sensors 45 a and 45 b are provided on the upper pieces 42 b and 43 b of the jogger fences 42 and 43 so that the recording medium S is detected from the upper side of the recording medium S. The first sensors 45a and 45b are housed in the notch holes 60 formed in the upper pieces 42b and 43b of the jogger fences 42 and 43, and the lower portions of the first sensors 45a and 45b in the notch holes 60 are formed by the light transmitting member 61. Covered.

  According to the present embodiment, dust such as paper dust is prevented from adhering to the first sensors 45a and 45b located above the recording medium S being conveyed, and the detection accuracy of the first sensors 45a and 45b is maintained. The Furthermore, by covering with the light transmissive member 61, adhesion of dust such as paper dust to the first sensors 45a and 45b is further prevented.

  A fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, transmissive sensors are provided on the jogger fences 42 and 43 as the first sensors 62 and 63. The first sensors 62 and 63 are respectively composed of light emitting parts 62a and 63a and light receiving parts 62b and 63b. The light emitting parts 62a and 63a are attached to the upper pieces 42b and 43b of the jogger fences 42 and 43, and the light receiving part 62b. 63b are attached to the lower pieces 42a and 43a of the jogger fences 42 and 43, respectively.

  The light emitting portions 62a and 63a and the light receiving portions 62b and 63b are attached to the jogger fences 42 and 43 by forming the cutout holes 51 and 60 and storing them. Further, the light emitting parts 62a, 63a and the light receiving parts 62b, 63b are covered with light transmissive members 52, 61.

  The surface of the light transmissive member 52 attached to the lower piece portions 42a and 43a and the surface of the lower piece portions 42a and 43a that are conveyance surfaces on which the recording medium S is conveyed are flush with each other. For this reason, the recording medium S to be conveyed does not interfere with the light transmissive member 52, and the conveyance when the recording medium S is conveyed above the light receiving parts 62b and 63b is performed smoothly.

  In the present embodiment, the light emitting units 62a and 63a are attached to the upper piece portions 42b and 43b, and the light receiving portions 62b and 63b are attached to the lower piece portions 42a and 43a. 63a may be attached to the lower pieces 42a and 43a, and the light receiving parts 62b and 63b may be attached to the upper pieces 42b and 43b.

1 is a schematic front view showing an internal structure of a color copying machine according to a first embodiment of the present invention. It is a perspective view which shows the part of the inversion unit containing a jogger fence. It is a top view which shows the part of the inversion unit containing a jogger fence. It is the sectional view on the AA line in FIG. It is a block diagram which shows the electrical connection of each part. It is explanatory drawing about an ear break detection, (a) is a top view which shows the positional relationship of a recording medium and a sensor, (b) is a timing chart which shows the output of a sensor. It is explanatory drawing about an ear break detection, (a) is a top view which shows the positional relationship of a recording medium and a sensor, (b) is a timing chart which shows the output of a sensor. It is explanatory drawing about the ear break detection in the 2nd Embodiment of this invention, (a) is a top view which shows the positional relationship of a recording medium and a sensor, (b) is a timing chart which shows the output of a sensor. . It is explanatory drawing about the ear break detection in the 3rd Embodiment of this invention, (a) is a top view which shows the positional relationship of a recording medium and a sensor, (b) is a timing chart which shows the output of a sensor. . It is sectional drawing which shows the part of the inversion unit containing the jogger fence in the 4th Embodiment of this invention. It is sectional drawing which shows the part of the inversion unit containing the jogger fence in the 4th Embodiment of this invention.

Explanation of symbols

3 Printer Engine 5 Fixing Device 12, 13, 14 Transport Paths 42, 43 Jogger Fence 44 Second Sensor, Reflective Sensors 45a, 45b First Sensor, Reflective Sensor 46 Second Sensor, Reflective Sensor 52 Light Transmissible Member 54 Light transmissive member 61 Light transmissive members 62, 63 First sensor, transmissive sensors 62a, 63a Light emitting part 62b, 63b Light receiving part S Recording medium

Claims (16)

A pair of jogger fences that can move in a direction in which the opposing distance is changed according to the size of the recording medium to be conveyed, holding both sides along the conveyance direction of the recording medium to be conveyed on the conveyance path,
A pair of first sensors that are provided on the jogger fence so as to be movable together with these jogger fences and detect both sides in the width direction of the recording medium to be conveyed,
A second sensor for detecting a center position of a substantially central portion in the width direction of the recording medium to be conveyed;
Means for detecting whether or not an ear fold has occurred in the recording medium from detection results of the first sensor and the second sensor;
A broken ear detection device.   The pair of first sensors and the second sensors are ear break detection devices according to claim 1, which are arranged on a straight line in a direction orthogonal to a recording medium conveyance direction.   The ear break detection device according to claim 1, wherein the second sensor is arranged at a position where the recording medium enters and exits a holding position by the jogger fence.   The detection as to whether or not an ear break has occurred is performed based on a detection result of the first sensor and the second sensor in a process in which a recording medium enters a holding position by the jogger fence. The broken ear detection device according to claim 1.   The detection of whether or not the ear break has occurred is based on the detection result of the first sensor and the second sensor in the process in which the recording medium goes out of the holding position by the jogger fence after the jogger processing by the jogger fence. The ear break detection device according to any one of claims 1 to 3, which is performed.   The ear break detection device according to any one of claims 1 to 5, wherein at least one of the first sensor and the second sensor is a reflective sensor.   The ear break detection device according to any one of claims 1 to 5, wherein at least one of the first sensor and the second sensor is a transmissive sensor.   The ear break detection device according to claim 6, wherein the reflection type sensor is arranged at a position for detecting the recording medium from below the recording medium.   9. The broken ear detection device according to claim 8, wherein the reflective sensor is covered with a light transmissive member.   The ear break detection device according to claim 9, wherein a surface of the light transmissive member and a transport surface on which the recording medium is transported are located in the same plane.   The ear break detection device according to claim 6, wherein the reflective sensor is disposed at a position where the recording medium is detected from above the recording medium.   The broken ear detection device according to claim 11, wherein the reflective sensor is covered with a light transmissive member.   One of the light emitting unit and the light receiving unit constituting the transmissive sensor is positioned below the recording medium to be transported, and the light emitting unit or the light receiving unit positioned below the transported recording medium is light transmissive. The ear break detection device according to claim 7 covered with a member.   The ear break detection device according to claim 13, wherein a surface of the light transmissive member and a transport surface on which the recording medium is transported are located in the same plane. Ear breakage detection device according to any one of claims 1 to 14,
A printer engine for forming an image in accordance with image data input to a recording medium to be conveyed;
An image forming apparatus. The image forming apparatus according to claim 15, further comprising a fixing device, wherein the ear fold detection device is provided downstream of the fixing device along a conveyance direction of the recording medium.

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