JP4689537B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying apparatus or a printer, and more particularly to an image forming apparatus having peripheral devices such as a mass feeding apparatus or a post-processing apparatus.

  In the image forming apparatus such as a copying apparatus or a printer, when the recording sheets are separated and fed one by one from the inside of the paper feeding cassette, the highest level recording loaded in the paper feeding cassette by pushing up the bottom plate of the paper feeding cassette. It is known that the recording paper is separated and fed by pressing the paper against the paper feed roller and rotating the paper feed roller in this state. In such an image forming apparatus, a feed failure occurs because the upper end of the front end fence of the paper feed cassette and the position of the uppermost recording paper differ depending on the amount of recording paper loaded in the paper feed cassette. Etsuimau. Therefore, in order to solve this problem, a sensor for detecting the position of the uppermost recording paper is provided, and this sensor is supported by a sensor holder supported by the cassette mounting portion so as to be movable up and down. A technique for providing a positioning hole for positioning and maintaining a constant distance between the upper end of the front end fence of the paper feed cassette and the sensor in a state where the positioning pin provided in the paper feed cassette is inserted into the positioning hole is, for example, `` Patent Document 1 ”discloses.

Japanese Utility Model Publication No. 2-97331

  In recent image forming apparatuses, recording paper on which an image is formed is diversified, and thereafter, processing, large-volume feeding, and the like are performed. Such operations such as post-processing and mass feeding are not performed by the apparatus main body of the image forming apparatus, but are performed by peripheral devices connected to the apparatus main body.

  The image forming operation in the image forming apparatus is provided with an intermediate sensor that detects when the recording paper fed from the paper feeding unit passes a predetermined position, and starts the image forming operation based on a signal from the intermediate sensor. However, when a peripheral device such as a large-volume feeder that feeds paper is installed, if the paper feed path from the peripheral device is different from the paper feed path from the inside of the main body, If an intermediate sensor cannot be provided inside the apparatus main body due to a problem, it is necessary to arrange the intermediate sensor inside the peripheral device. If the intermediate sensor is placed inside the peripheral device, the distance from the pair of registration rollers and the registration sensor placed in the main body of the device to the intermediate sensor increases, and the variation in distance increases, resulting in a shift in timing during recording paper conveyance. This is likely to cause problems such as misalignment of the leading edge, skew failure due to insufficient slack formation at the registration roller pair, and recording paper conveyance jam due to detection timing deviation. In addition, if control is performed so as not to cause the above-described problems, it is necessary to provide a margin for the control, and narrow control between papers cannot be performed and productivity cannot be improved. is there. This problem may also occur in peripheral devices that perform post-processing operations such as sorting and stapling.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of improving productivity without causing problems even when peripheral devices are connected.

  According to a first aspect of the present invention, there is provided an image forming apparatus in which a peripheral device is connected to the apparatus main body, and transfer paper is transported between the apparatus main body and the peripheral apparatus. The peripheral device has transfer paper detection means that can move the transfer paper in the transfer paper conveyance direction, and the transfer paper detection means is positioned when the peripheral device is connected to the apparatus body. Is performed.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the transfer paper detecting means is supported by a transfer paper guide member provided in the peripheral device.

  According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the transfer paper detecting means is further attached to a support member that is movable in the transfer paper conveyance direction, and the peripheral device is attached to the apparatus body The transfer paper detecting means is positioned by the support member coming into contact with a stationary member provided in the apparatus main body.

  According to a fourth aspect of the present invention, there is provided an image forming apparatus in which a peripheral device is connected to the apparatus main body, and transfer paper is transported between the apparatus main body and the peripheral apparatus, between the peripheral device and the apparatus main body. The apparatus main body has transfer paper detecting means that can move the transfer paper in the thickness direction, and the transfer paper detecting means is positioned when the peripheral device is connected to the apparatus main body. Is performed.

  According to a fifth aspect of the present invention, in the image forming apparatus according to the fourth aspect, the transfer paper detecting means is supported by a stationary member provided in the apparatus main body.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth or fifth aspect, the transfer paper detection means is attached to a support member that is movable in the transfer paper thickness direction and has a fitting hole. When the peripheral device is connected to the apparatus main body, the transfer paper detecting means is positioned by fitting a positioning member provided in the peripheral device into the fitting hole. .

  According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, a first paper feed unit that feeds transfer paper from the apparatus main body, and image formation on the transfer paper An image forming unit that performs transfer, a first transport roller pair that transports transfer paper from the first paper feed unit toward the image forming unit, and a second paper feed unit that feeds transfer paper from the peripheral device And a second transport roller pair for transporting transfer paper from the second paper feed unit toward the image forming unit, and the first transport roller pair and the second transport roller pair are common to each other. It is characterized by being driven to rotate by the driving means.

  According to an eighth aspect of the present invention, in the image forming apparatus according to the seventh aspect of the present invention, the driving unit is capable of forward and reverse rotation, and when the driving unit rotates forward, the first sheet feeding unit is provided by the first conveying roller pair. The transfer sheet is conveyed from the second sheet feeding unit to the image forming unit by the second conveyance roller pair when the driving unit is rotated in the reverse direction. Features.

  According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect, each of the conveying roller pairs further has a one-way clutch, and each of the conveying roller pairs rotates only in a direction in which the transfer paper is conveyed toward the image forming unit. The transfer sheet is configured such that the transfer sheet is not temporarily stopped in a state in which the transfer sheet enters the contact portion of each roller in each of the transport roller pairs.

  According to a tenth aspect of the present invention, in the image forming apparatus according to the ninth aspect, the transfer paper detecting means is further arranged on the upstream side in the transfer paper conveyance direction of the second conveyance roller pair.

  According to the present invention, it is possible to accurately position the transfer paper detection unit that determines the latent image formation timing in the image forming unit with respect to the registration roller pair and the registration sensor. The position can be detected with high accuracy, and if the transfer paper position is not detected with high accuracy, the registration sensor detection timing misalignment, leading edge registration misalignment, and skew due to insufficient slack formation in the pair of registration rollers Occurrence of a defect such as a correction failure can be prevented.

  FIG. 1 shows an image forming apparatus employing the first embodiment of the present invention. In FIG. 1, an image forming apparatus 1 has an image forming apparatus main body 2 as an apparatus main body and a large-capacity paper feeding device 3 as a peripheral device.

  A photoconductive drum 4 constituting an image forming unit is arranged inside the image forming apparatus main body 2, and a charging device, a developing device, a static eliminating device, a cleaning device, etc. (not shown) are arranged around the photoconductive drum 4, respectively. Has been. An exposure device (not shown) is disposed above the photosensitive drum 4, and an electrostatic latent image is formed on the peripheral surface of the photosensitive drum 4 by the light 5 emitted from the exposure device.

  Below the image forming apparatus main body 2, paper feed cassettes 6, 7, and 8 that store a large number of transfer sheets P are detachably attached to the image forming apparatus main body 2. , 7 and 8, in the vicinity of the paper feed cassettes 6, 7, and 8, paper feed rollers 9, 10, and 11 for pulling out the transfer paper P from the paper feed cassettes 6, 7 and 8, and separation roller pairs 12 and 13 for separating and feeding the drawn transfer paper P. , 14 are arranged. Conveying roller pairs 15, 16, and 17 are disposed downstream of the separating roller pairs 12, 13, and 14 in the transfer sheet conveying direction. , 10, 11, the separation roller pairs 12, 13, and 14, and the transport roller pairs 15, 16, and 17 constitute a first paper feeding unit 18.

  A transfer paper transport roller pair 19 that is a first transport roller pair is disposed downstream of the transport roller pair 15 in the transfer paper transport direction, and a transfer paper transport roller pair 19 is disposed downstream of the transfer paper transport direction. Is provided with a transfer paper detection sensor 20 for detecting the transfer paper P conveyed by the. The configuration of the transfer paper transport roller pair 19 will be described later. Based on a detection signal from the transfer paper detection sensor 20, light 5 is irradiated from the exposure device toward the photosensitive drum 4.

  On the downstream side of the transfer paper conveyance roller pair 19 in the transfer paper conveyance direction, a registration roller pair 21 is disposed that temporarily stops the transfer paper P and then feeds it at a predetermined timing. A registration sensor 22 for detecting that the leading edge of the transfer paper P has reached 21 is disposed. The registration roller pair 21 is driven based on a signal from the registration sensor 22.

  A transfer belt 23 for transferring the toner image formed on the photoconductor 4 onto the transfer paper P is disposed downstream of the registration roller pair 21 in the transfer paper conveyance direction and below the photoconductor drum 4. . A bias from a bias applying unit (not shown) is applied to the transfer belt 23, and the toner image formed on the photoreceptor 4 is electrostatically transferred onto the transfer paper P by this bias. A fixing device 24 is disposed downstream of the transfer belt 23 in the conveyance direction of the transfer paper. The fixing device 24 includes a heating roller having a heat source therein and a pressure roller pressed against the heating roller, and fixes the transfer image electrostatically transferred onto the transfer paper P by heating and pressing. .

  On the downstream side of the fixing device 24 in the transfer sheet conveyance direction, a discharge roller pair 25 for discharging the fixed transfer sheet to the outside of the image forming apparatus main body 2 is disposed. The transfer paper discharged by the discharge roller pair 25 is discharged onto a discharge tray 26 disposed outside the image forming apparatus main body 2. A transfer paper reversing device 27 is disposed below the transfer belt 23 and the fixing device 24. The transfer paper reversing device 27 includes a roller 28 and a roller pair 29 that can be rotated forward and backward, a pair of reverse conveying rollers 30, 31, 32, and the like, and a roller 28 that normally rotates the transfer paper P on which image formation has been performed on one side. Then, the roller 28 and the roller pair 29 are reversed and sent to the conveyance path 34 to join the conveyance path 35 from the first paper supply unit 18.

  The large capacity sheet feeding device 3 attached to the side surface of the image forming apparatus main body 2 is positioned in the left and right direction and the depth direction in FIG. 1 with respect to the image forming apparatus main body 2 by a positioning member and a lock member (not shown). And mechanically connected by an interface cable (not shown).

  Inside the large-capacity paper feeder 3, a stock unit 36 capable of storing transfer paper P in units of several thousand sheets is disposed. Above the stock unit 36, the transfer paper stored on the stock unit 36 is disposed. A paper feed roller 37 for pulling out P and a separation roller pair 38 for separating and feeding the drawn transfer paper P are provided. A conveyance roller pair 39 is disposed on the downstream side of the separation roller pair 38 in the conveyance direction of the transfer paper. The stock unit 36, the paper supply roller 37, the separation roller pair 38, and the conveyance roller pair 39 serve as a second paper supply unit. 40 is configured.

  A transfer paper transport roller pair 41, which is a second transport roller pair, is disposed at a position located downstream of the transport roller pair 39 in the transfer paper transport direction and upstream of the registration roller pair 21 in the transfer paper transport direction. A transfer paper detection sensor 42 as a transfer paper detection means for detecting the transfer paper P conveyed to the transfer paper conveyance roller pair 41 is disposed upstream of the transfer paper conveyance direction. The configuration of the transfer paper transport roller pair 41 and the support configuration of the transfer paper detection sensor 42 will be described later. Based on the detection signal from the transfer paper detection sensor 42, the light 5 is irradiated from the exposure device toward the photosensitive drum 4.

  Here, the configuration of the transfer paper transport roller pair 19, 41 will be described. As shown in FIG. 2, the image forming apparatus main body 2 is provided with a motor 43 as a drive means capable of forward and reverse rotation, and a pulley 44 is attached to the output shaft thereof. The pair of transfer paper transport rollers 19 includes a driving roller 19a and a driven roller 19b pressed against the driving roller 19a. A driving gear 45 is mounted on the same axis as the driving roller 19a. An idle gear 46 meshing with the drive gear 45 is rotatably disposed in the image forming apparatus main body 2 located in the vicinity of the drive gear 45, and a pulley 47 is attached on the same axis. The pair of transfer paper transport rollers 41 includes a driving roller 41a and a driven roller 41b pressed against the driving roller 41a. A pulley 48 is attached on the same axis as the driving roller 41a. An idle pulley 49 is disposed between the pulleys 44 and 47, an idle pulley 50 is disposed between the pulleys 47 and 48, and an idle pulley 51 is disposed between the pulleys 44 and 48, respectively. Reference numerals 50 and 51 are rotatably supported by the image forming apparatus main body 2, and only the idle pulley 50 is configured to be movable. A timing belt 52 is wound around the pulleys 44, 47, 48 and the idle pulleys 49, 50, 51, and a predetermined tension is applied to the timing belt 52 by moving the timing pulley 50.

  With the above configuration, when the motor 43 rotates forward and the pulley 44 rotates clockwise in FIG. 2, the drive roller 19a rotates counterclockwise in FIG. 2 via the pulley 47, idle gear 46, and drive gear 45. The transfer paper P fed from the first paper feed unit 18 is conveyed in the direction of arrow A. When the motor 43 reverses and the pulley 44 rotates counterclockwise in FIG. 2, the drive roller 41 a rotates counterclockwise in FIG. 2 via the pulley 48 and feeds from the second paper feed unit 40. The transferred transfer paper P is conveyed in the direction of arrow B.

  In the above configuration, when the motor 43 is rotating forward, the driving roller 41a rotates clockwise in FIG. 2, and when the motor 43 is rotating backward, the driving roller 19a rotates clockwise in FIG. As a result, the transfer paper P is transported in the direction opposite to the transfer paper transport direction, so that the rotational force in the counterclockwise direction with respect to the drive roller 19a is provided between the drive roller 19a and the drive gear 45. Between the drive roller 41a and the pulley 48, a one-way clutch 53 that transmits only the counterclockwise rotational force to the drive roller 41a is interposed. Thus, when the motor 43 rotates in the forward direction, only the transfer sheet conveying roller pair 19 is driven to transfer the transfer sheet P fed from the first sheet feeding unit 18 in the direction of arrow A, and when the motor 43 rotates in the reverse direction, the transfer sheet is transferred. Only the transport roller pair 41 is operated, and the transfer paper P fed from the second paper feed unit 40 is transported in the direction of arrow B.

  However, when the timing belt 52 to which a tension of a predetermined value or more is applied for driving transmission as in the configuration shown in the present embodiment, the driving is transmitted by the radial load, which is opposite to the intended one. There is a risk that the transfer paper P will be fed back by driving the transfer paper conveyance roller pair on the side. Therefore, in the present invention, when the transfer paper P enters between the rollers 19a, 19b and 41a, 41b constituting the transfer paper transport roller pairs 19, 41, the operation of the transfer paper transport roller pairs 19, 41 is temporarily performed. Control so as not to stop. Thereby, even if each transfer paper conveyance roller pair 19 and 41 reverse | inverts, generation | occurrence | production of the malfunction by which the transfer paper P is sent back can be prevented. In the present embodiment, the transfer paper detection sensor 42 is disposed upstream of the transfer paper transport roller pair 41 in the transfer paper transport direction in order to reliably perform the transfer paper stop control. Below, the support structure of the transfer paper detection sensor 42 is demonstrated.

  As shown in FIG. 3, a transfer paper detection sensor is provided at the outlet of the large capacity sheet feeding device 3 on the downstream side in the transfer paper transport direction of the pair of transport rollers 39 and the transfer paper P is delivered to the image forming apparatus main body 2. 42 is disposed. The transfer paper detection sensor 42 is attached to a bracket 55 as a support member by a snap fit method. The bracket 55 is inserted into a long hole formed in an attachment member 56 fixed to the large-capacity paper feeding device 3 and a step screw 57. Is supported so as to be movable in the transfer paper conveyance direction. Also, as shown in FIG. 4, two compression springs 58 are disposed between the wall surface of the attachment member 56 and the wall surface of the bracket 55 in the transfer paper transport direction, and the bracket 55 transports the transfer paper. It is always urged toward the downstream side.

  On the other hand, in the image forming apparatus main body 2, a receiving member 61 is disposed as a stationary member fixedly supported between the front side plate 59 and the rear side plate 60 of the image forming apparatus main body 2. Since the receiving member 61 is fixedly supported between the front side plate 59 and the rear side plate 60 similarly to the registration roller pair 21 and the registration sensor 22, the registration roller pair 21, the registration sensor 22, and the receiving member 61 in the transfer paper transport direction. Are configured with high accuracy.

  With the above configuration, when the large-capacity sheet feeding device 3 is connected to the image forming apparatus main body 2, the bracket 55 is brought into contact with the outer surface of the receiving member 61 as shown in FIG. 55 is pushed against the urging force of the compression spring 58 in the direction opposite to the transfer sheet conveyance direction, and the positioning of the bracket 55 and the transfer sheet detection sensor 42 attached thereto in the transfer sheet conveyance direction is performed. Accordingly, the transfer paper detection sensor 42 that determines the latent image formation timing in the image forming unit can be accurately positioned with respect to the registration roller pair 21 and the registration sensor 22, and thus is conveyed from the large-capacity paper feeding device 3. The position of the transfer paper P to be detected can be accurately detected. As a result, when the position of the transfer paper P is not detected accurately, the registration sensor detection timing misalignment, the tip registration misalignment, the registration roller pair 21 It is possible to prevent the occurrence of a problem such as a skew correction failure due to insufficient slack formation. In addition, since the position of the transfer paper P fed from a peripheral device such as the large-capacity paper feeder 3 can be accurately detected, it is possible to control the feeding between the transfer papers. Even at the paper conveyance speed, the number of transfer sheets on which image formation is possible can be increased, and productivity can be improved.

  FIG. 6 shows a second embodiment of the present invention. Compared with the first embodiment shown in FIG. 3, the second embodiment uses an attachment member 62 instead of the attachment member 56, and is formed on the attachment member 62 by a step screw 57 instead of the bracket 55. The bracket 63 as a support member supported so as to be movable in the transfer paper conveyance direction in the elongated hole is used, the transfer paper detection sensor 42 is attached to the bracket 63 by a snap fit method, The difference is that a tension spring 64 is provided between the wall surface and the wall surface of the bracket 63 in the transfer paper conveyance direction.

  According to the second embodiment, when the large capacity sheet feeding device 3 is connected to the image forming apparatus main body 2, the outer surface of the bracket 63 comes into contact with the outer surface of the receiving member 61. Is pushed against the urging force of the tension spring 64 in the direction opposite to the transfer sheet conveyance direction, and the bracket 63 and the transfer sheet detection sensor 42 attached thereto are positioned in the transfer sheet conveyance direction. Thereby, the same effect as 1st Embodiment can be acquired.

  In each of the above embodiments, a reflective sensor is used as the transfer paper detection sensor 42, but a transmissive sensor having a filler may be used. In the configuration described above, as shown in FIG. 7, the distance a of the transfer sheet detection sensor 42 to the transfer sheet P fed from the large capacity sheet feeder 3 is determined by a small number of parts on the large capacity sheet feeder 3 side. Therefore, the distance accuracy is increased, and for example, special paper whose format is pre-printed on the surface such as label paper, delivery slip, and pressure-sensitive paper can be reliably detected. When the reflection type sensor is used, the distance a between the transfer paper P and the transfer paper detection sensor 42 must be within a certain range (3 to 7 mm in this embodiment) due to its characteristics, and has a filler. When the transmissive sensor is used, if the distance between the transfer paper P and the transmissive sensor varies, the on-timing of the sensor by the filler varies even at the same transfer paper position.

  FIG. 8 shows a third embodiment of the present invention. Compared with the first embodiment shown in FIG. 3, the third embodiment uses a receiving member 61 as an attachment member instead of the attachment member 56, and has a slotted hole instead of the bracket 55. A bracket 67 as a support member supported so as to be movable in the thickness direction of the transfer paper on the receiving member 61 by 65, 66, a point that the transfer paper detection sensor 42 is attached to the bracket 67 by a snap-fit method, The large-capacity paper feeding device 3 is different in that it includes a positioning member 68 having a tapered portion at a tip end that can be fitted into a fitting hole 67 a formed in the bracket 67.

  According to the third embodiment, when the large capacity sheet feeding device 3 is connected to the image forming apparatus main body 2, the positioning member 68 is fitted into the fitting hole 67a as shown in FIG. The bracket 67 moves in the transfer sheet thickness direction, and the transfer sheet detection sensor 42 is positioned in the transfer sheet thickness direction. In the third embodiment, since the position of the transfer paper detection sensor 42 in the transfer paper conveyance direction is determined by the receiving member 61, the position accuracy of the transfer paper detection direction of the transfer paper detection sensor 42 in the transfer paper conveyance direction is accurately determined. At the same time, the position of the transfer paper detection sensor 42 in the thickness direction of the transfer paper is moved in the transfer paper thickness direction while the fitting hole 67a is scooped by the taper portion of the positioning member 68. Thus, the transfer paper P can be reliably detected by keeping the distance a constant with respect to the distance a between the distance and the distance a.

  FIG. 10 shows a fourth embodiment of the present invention. Compared with the first embodiment shown in FIG. 3, the fourth embodiment uses an attachment member 70 fixed to the transfer paper guide member 69 of the large-capacity paper feeder 3 in place of the attachment member 56. Is different.

  According to the fourth embodiment, when the large-capacity paper feeding device 3 is connected to the image forming apparatus main body 2, the outer surface of the bracket 55 contacts the outer surface of the receiving member 61 as shown in FIG. By contact, the bracket 55 is pushed in the direction opposite to the transfer sheet conveyance direction against the urging force of the compression spring 58, and the bracket 55 and the transfer sheet detection sensor 42 attached thereto are positioned in the transfer sheet conveyance direction. Done. Thereby, the configuration of the transfer paper detection sensor 42 and the transfer paper P can be improved in accuracy by simplifying the configuration as compared with the first embodiment, and the detection accuracy of the transfer paper P can be improved as compared with the first embodiment. Can be improved.

  FIG. 12 shows a fifth embodiment of the present invention. Compared with the fourth embodiment shown in FIG. 10, the fifth embodiment uses an attachment member 71 fixed to the transfer paper guide member 69 instead of the attachment member 70, and is long in place of the bracket 55. A transfer paper detection sensor 42 is attached to the bracket 73 by a snap-fit method, using a bracket 73 as a support member that has a hole and is supported on the attachment member 71 by a step screw 72 so as to be movable in the transfer paper conveyance direction. In addition, a bracket 73 and a compression spring 74 that urges the transfer paper detection sensor 42 toward the downstream side in the transfer paper conveyance direction are disposed between the wall surface of the attachment member 71 and the transfer paper detection sensor 42. Is different.

  According to the fifth embodiment, when the large-capacity sheet feeding device 3 is connected to the image forming apparatus main body 2, the tip 73 a of the bracket 73 comes into contact with the outer surface of the receiving member 61, thereby the bracket 73. Is pushed against the urging force of the compression spring 74 in the direction opposite to the transfer sheet conveyance direction, and the bracket 73 and the transfer sheet detection sensor 42 attached thereto are positioned in the transfer sheet conveyance direction. Thereby, the same effect as the fourth embodiment can be obtained.

  As shown in the first, second, fourth, and fifth embodiments described above, when the transfer paper detection sensor 42 is disposed in the large-capacity paper feeder 3 that is an optional peripheral device, the third As shown in the embodiment, since it is not necessary to provide the transfer paper detection sensor 42 on the image forming apparatus main body 2 side, the components on the image forming apparatus main body 2 side can be simplified, and the size and the space can be saved. Can be achieved.

  In each of the above embodiments, an example in which the large-capacity paper feeding device 3 is used as a peripheral device connected to the image forming apparatus main body 2 has been described. However, peripheral devices to which the present invention can be applied are not limited thereto, and the image forming apparatus The present invention can also be applied to post-processing devices such as finishers and other peripheral devices in which the transfer direction of the transfer paper P is downstream with respect to the main body 2.

1 is a schematic front view of an image forming apparatus employing a first embodiment of the present invention. It is the schematic explaining the drive structure of the 1st and 2nd conveyance roller pair used for each 1st thru | or 5th embodiment of this invention. It is the schematic explaining the attachment structure of the transfer paper detection sensor used for the 1st Embodiment of this invention. It is a schematic plan view explaining the positional relationship of the bracket used for the 1st Embodiment of this invention, an attachment member, a step screw, and a compression spring. FIG. 3 is a schematic diagram illustrating a positioning mode of a transfer paper detection sensor when a large-capacity paper feeding device is connected to the image forming apparatus main body according to the first embodiment of the present invention. It is the schematic explaining the attachment structure of the transfer paper detection sensor used for the 2nd Embodiment of this invention. It is the schematic explaining the space | interval of the transfer paper detection sensor and transfer paper used for each embodiment of this invention. It is the schematic explaining the attachment structure of the transfer paper detection sensor and positioning member used for the 3rd Embodiment of this invention. FIG. 10 is a schematic diagram illustrating a positioning mode of a transfer paper detection sensor when a large-capacity paper feeding device is connected to an image forming apparatus main body according to a third embodiment of the present invention. It is the schematic explaining the attachment structure of the transfer paper detection sensor used for the 4th Embodiment of this invention. FIG. 10 is a schematic diagram illustrating a positioning mode of a transfer paper detection sensor when a large-capacity paper feeding device is connected to an image forming apparatus main body according to a fourth embodiment of the present invention. It is the schematic explaining the attachment structure of the transfer paper detection sensor used for the 5th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Apparatus main body (image forming apparatus main body)
3 Peripheral devices (large capacity paper feeder)
4 Image forming unit (photosensitive drum)
18 First paper feeding section 19 First transport roller pair (transfer paper transport roller pair)
40 Second paper feed section 41 Second transport roller pair (transfer paper transport roller pair)
42 Transfer paper detection means (transfer paper detection sensor)
43 Drive means (motor)
53, 54 One-way clutch 55, 63, 67, 73 Support member (bracket)
61 Immovable member (receiving member)
67a Fitting hole 68 Positioning member 69 Transfer paper guide member P Transfer paper

Claims (10)

In an image forming apparatus in which peripheral devices are connected to the apparatus main body, and transfer paper is transported between the apparatus main body and the peripheral devices.
The peripheral device has transfer paper detecting means that can detect transfer paper conveyed between the peripheral device and the apparatus main body and is movable in the transfer paper conveyance direction, and the peripheral device is connected to the apparatus main body. The image forming apparatus is characterized in that the transfer paper detecting means is positioned when the image forming apparatus detects the transfer paper. The image forming apparatus according to claim 1.
The image forming apparatus, wherein the transfer paper detecting means is supported by a transfer paper guide member provided in the peripheral device. The image forming apparatus according to claim 1 or 2,
The transfer paper detecting means is attached to a support member movable in the transfer paper transport direction, and the support member contacts a stationary member provided in the apparatus main body when the peripheral device is connected to the apparatus main body. By doing so, the transfer sheet detecting means is positioned. In an image forming apparatus in which peripheral devices are connected to the apparatus main body, and transfer paper is transported between the apparatus main body and the peripheral devices.
The apparatus main body has transfer paper detection means that can detect transfer paper conveyed between the peripheral device and the apparatus main body, and is movable in the transfer paper thickness direction, and the peripheral apparatus is connected to the apparatus main body. The image forming apparatus is characterized in that the transfer paper detecting means is positioned when the image forming apparatus detects the transfer paper. The image forming apparatus according to claim 4.
The image forming apparatus, wherein the transfer sheet detecting means is supported by a stationary member provided in the apparatus main body. The image forming apparatus according to claim 4 or 5, wherein:
The transfer paper detection means is movable to the transfer paper thickness direction and is attached to a support member having a fitting hole, and when the peripheral device is connected to the apparatus main body, An image forming apparatus, wherein a positioning member provided in a peripheral device is fitted to position the transfer paper detecting means. The image forming apparatus according to any one of claims 1 to 6,
A first paper feeding unit that feeds transfer paper from the apparatus main body; an image forming unit that forms an image on the transfer paper; and a first paper feeding unit that transfers the transfer paper from the first paper feeding unit toward the image forming unit. A pair of conveying rollers, a second sheet feeding unit that feeds transfer paper from the peripheral device, and a second pair of conveying rollers that conveys the transfer sheet from the second sheet feeding unit toward the image forming unit. An image forming apparatus characterized in that the first transport roller pair and the second transport roller pair are rotationally driven by a common driving unit. The image forming apparatus according to claim 7.
The driving means is capable of forward and reverse rotation. When the driving means rotates forward, the transfer paper is conveyed from the first paper feeding unit to the image forming unit by the first conveying roller pair, and the driving unit is rotated in reverse. In this case, the transfer paper is conveyed from the second paper feeding unit to the image forming unit by the second conveyance roller pair. The image forming apparatus according to claim 8.
Each of the conveying roller pairs has a one-way clutch and is configured to be rotatable only in the direction of conveying the transfer sheet toward the image forming unit. An image forming apparatus, wherein the transfer paper is not temporarily stopped in a state where the transfer paper enters. The image forming apparatus according to claim 9.
The image forming apparatus, wherein the transfer paper detecting means is disposed upstream of the second transport roller pair in the transfer paper transport direction.

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