JP2021066574A - Sheet conveyance device and image formation device - Google Patents

Abstract

To provide a sheet conveyance device capable of suppressing erroneous detection of an optical sensor and arranging a member on an opposite side of a second guide member, and an image formation device.SOLUTION: A sheet conveyance device includes: a first guide member 62; a second guide member 63 facing the first guide member 62; and an optical sensor 80 which is arranged on the first guide member side to optically detect a sheet conveyed in a sheet conveyance path formed between the first guide member 62 and the second guide member 63. Further, a through hole 63a is provided in a facing region to the optical sensor 80 of the second guide member 63, and a cross-sectional recessed shape part 174 or a through hole is provided at the part, facing the through hole 63a, of a member 71 arranged on the opposite side to the conveyance path side of the second guide member 63 so that a part of which faces the through hole 63a of the second guide member 63.SELECTED DRAWING: Figure 6

Description

The present invention relates to a sheet transfer device and an image forming device.

Conventionally, in the sheet transport path formed between the first guide member, the second guide member facing the first guide member, and the first guide member side, and formed between the first guide member and the second guide member. There is known a sheet transfer device having an optical sensor that optically detects the sheet that has been transported.

In Patent Document 1, as the sheet transport device, a concave portion recessed on the side opposite to the optical sensor side is provided in a region of the second guide member facing the optical sensor for the purpose of suppressing false detection of the optical sensor. The concave portion provided with the light reflection preventing means is described.

However, in the sheet transport device of Patent Document 1, the member cannot be arranged on the side opposite to the transport path side of the second guide member due to the concave portion of the second guide member.

In order to solve the above-mentioned problems, the present invention comprises a first guide member, a second guide member facing the first guide member, and the first guide member and the first guide member arranged on the first guide member side. In a sheet transfer device having an optical sensor that optically detects a sheet conveyed in a sheet transfer path formed between the second guide member and the second guide member, a region of the second guide member facing the optical sensor. Is provided with a through hole, and a portion of the member is arranged so as to face the through hole of the second guide member on the side opposite to the transport path side of the second guide member. It is characterized in that a portion or a through hole is provided.

According to the present invention, it is possible to suppress erroneous detection of the optical sensor and arrange the member on the opposite side of the second guide member.

The schematic block diagram of the printer which concerns on this embodiment. The perspective view which shows the state which the drawer unit of this embodiment is located at the storage position inside the printer main body which is a device main body. The perspective view which shows the state which the drawer unit was pulled out to the drawer position which is the non-storage position outside the printer main body. A cross-sectional view showing a locked resist unit in a cross section orthogonal to the axial direction of a pair of resist rollers. A cross-sectional view showing a resist unit in an unlocked state in a cross section orthogonal to the axial direction of a pair of resist rollers. FIG. 4A is a sectional view taken along the line AA of FIG. The schematic block diagram which shows the example which arranged the lock lever shaft on the downstream side in the paper transport direction with respect to the paper detection sensor. The side view which shows the method of fixing the 1st shaft member and the 2nd shaft member to the connecting member.

Hereinafter, as an image forming apparatus including the sheet transporting apparatus according to the present invention, an electrophotographic printer (hereinafter, simply referred to as a printer) that forms an image by an electrophotographic method will be described.
In the present embodiment, a color laser printer will be described as an example of the image forming apparatus. However, the image forming apparatus is not limited to a color one and may be a monochrome one. Other image forming apparatus may be used. Further, the image forming apparatus provided with the sheet transporting apparatus according to the present invention is not limited to the electrophotographic method, and may be an image forming device of another type such as an inkjet method.

FIG. 1 is a schematic configuration diagram of a printer 100 according to this embodiment.
The printer 100 is provided with an intermediate transfer belt 16 arranged in the intermediate transfer unit at substantially the center of the printer main body 1. Above the intermediate transfer belt 16, four image forming units 2Y, 2M, 2C, and 2K that image with toners of each color of yellow (Y), cyan (C), magenta (M), and black (K) are provided. They are arranged side by side. Since the configurations and operations of the four image forming units 2Y, 2M, 2C, and 2K are substantially the same, the image forming units will be described here by omitting the reference numerals indicating colors.

The image forming unit 2 includes a photoconductor 12 which is a latent image carrier facing the upholstery surface of the upper part of the intermediate transfer belt 16, and a charging device 11 which is a charging means and a latent image forming are formed around the photoconductor 12. It includes a laser scanning unit 10 which is a means, a developing device 13 which is a developing means, and the like. Further, a primary transfer roller 14 is provided so as to face the photoconductor 12 with the intermediate transfer belt 16 interposed therebetween, and a primary transfer nip is formed.

Further, a secondary transfer roller 15 is provided below the intermediate transfer belt 16, and a secondary transfer opposed roller 16a facing the secondary transfer roller 15 with the intermediate transfer belt 16 interposed therebetween is provided to form a secondary transfer nip. ..

At the bottom of the printer main body 1, a paper feed device 200 in which the first to third three-stage paper feed trays 5 can be pulled out from the device main body is provided, and each paper feed tray 5 is provided with transfer paper or resin. Paper P as a recording material made of a film or the like is accommodated.

When the printing operation is started by the printer 100, the photoconductor 12 is rotationally driven in the counterclockwise direction in FIG. 1, and the intermediate transfer belt 16 is rotationally driven in the clockwise direction in FIG. At this time, the surface of the photoconductor 12 is uniformly charged to a predetermined polarity by the charging device 11. Next, the surface of the uniformly charged photoconductor 12 is irradiated with laser light based on image information from the laser scanning unit 10 of each color, whereby an electrostatic latent image is formed on the photoconductor 12. Then, the electrostatic latent image formed on the surface of the photoconductor 12 is visualized as a toner image by the developing device 13, and the toner image is transferred to the intermediate transfer belt 16 by the primary transfer roller 14 at the primary transfer nip. .. The transfer residual toner adhering to the surface of the photoconductor 12 after the toner image is transferred is removed by the photoconductor cleaning device.

At the time of color image formation, the above-mentioned image forming operation is performed in all the image forming units 2, and the yellow toner image, the cyan toner image, the magenta toner image, and the black toner image formed on the individual photoconductors 12 are intermediate. It is sequentially stacked and transferred on the transfer belt 16.

On the other hand, the paper P is fed from the paper feed device 200. When the user selects the paper feed tray 5 to be used from the three-stage paper feed tray 5 using an input terminal such as an operation panel 3 or a personal computer, the paper P stored in the selected paper feed tray 5 is released. It is fed.
The broken line indicated by the reference numeral “19” in FIG. 1 indicates a transport path through which the paper P passes through the printer 100.

The paper P that has been fed is sent out toward the resist roller pair 18, and the tip of the paper is abutted against the resist roller pair 18 in the stopped pressure contact state. After the skew correction (skew correction) of the paper P is performed by this, the resist roller pair 18 feeds the paper P toward the secondary transfer nip at a timing that matches the toner image on the intermediate transfer belt 16.

A paper detection sensor 80 composed of a reflective optical sensor is arranged near the downstream side of the resist roller pair 18 in the paper transport direction. The tip of the paper pulled out from the resist roller pair 18 is detected by the paper detection sensor 80, and the deceleration timing of the paper transport speed is determined based on the detection result. Then, the transfer speed is reduced to a predetermined paper transfer speed at the determined timing, and the transfer residual toner adhering to the surface of the intermediate transfer belt 16 after the toner image is transferred at the secondary transfer nip is removed by the intermediate transfer belt cleaning device. ..

The paper P on which the toner image is transferred by the secondary transfer nip is sent to the fixing device 17, and after the toner image is fixed on the paper P, it is discharged to the paper ejection tray 4 in the case of single-sided printing. In the case of double-sided printing, the paper P on which the image is formed on the first surface is conveyed to the double-sided path by switching the conveying path by the branch claw 40. The paper P fed to the reversing roller pair 41 by the branch claw 40 is conveyed to the double-sided roller pair 42 by the forward / reversal of the reversing roller pair 41. At this time, the front and back sides of the paper P with respect to the transport direction are reversed from those at the time of forming the first surface image. Then, after the paper P is conveyed to the relay roller pair 43 and the resist roller pair 18, the image is formed on the second surface by the same process as described above, and then the paper P is discharged to the paper ejection tray 4.

A bypass tray 201 is provided on the right side surface in the drawing of the apparatus, and the paper fed from the bypass tray 201 is carried in from the carry-in unit D and is conveyed toward the resist roller pair 18 by the carry-in roller pair 44. .. As an option, the user can connect a paper feed bank capable of feeding a large amount of paper P to the printer main body 1 to the right side surface in the drawing of the apparatus. In this case, the side cover provided with the bypass tray 201 is removed, and the side cover to which the paper feed bank can be connected is attached. The paper fed from the paper feed bank is carried in from the carry-in portion D provided on the right side surface in the drawing of the apparatus main body as in the case of the manual feed tray 201, and is carried toward the resist roller pair 18 by the carry-in roller pair 44. Will be done. Further, instead of the output tray 4, it is also possible to connect a finisher capable of stitch binding and folding.

Further, in the present embodiment, a drawer unit 30 that can be pulled out from the front of the printer main body 1 is provided in order to enable paper jam processing when paper jam occurs. The drawer unit 30 is arranged between the resist unit 60 as a sheet transfer device including the resist roller pair 18, the secondary transfer roller 15, the fixing device 17, the secondary transfer roller 15, and the fixing device 17, and holds the paper P. It holds a transport belt 45, a branch claw 40, a transport path 19, and the like for transport.

Next, the drawer unit 30 in this embodiment will be described.
FIG. 2 is a perspective view showing a state in which the drawer unit 30 of the present embodiment is located at a storage position inside the printer main body 1 which is the main body of the apparatus.
FIG. 3 is a perspective view showing a state in which the drawer unit 30 is pulled out to a drawer position which is a non-storage position outside the printer main body 1.

In the present embodiment, the drawer unit 30 is provided on the printer main body 1 so as to be slidable along the front-rear direction of the device by the slide rail 6 which is a holding means. When a jam of paper P occurs in the vicinity of the registration roller pair 18, the user moves the drawer unit 30 from the storage position in the printer main body 1 shown in FIG. 2 to the front side of the device, and the drawer position (non-storage) shown in FIG. Pull it out to the position) and perform paper jam processing. At the drawer position, the user can perform a paper jam process on the paper P sandwiched between the resist rollers 18 by releasing the pressure contact state of the resist rollers 18 and switching to the non-pressure contact state. it can. After the paper jam processing is completed, the user performs an operation of switching the resist roller pair 18 to the pressure welding state again, and then pushes the drawer unit 30 to the storage position shown in FIG. As a result, skew correction (skew correction) and paper transfer by the resist roller pair 18 in the pressure-welded state can be performed again.

4 and 5 are cross-sectional views showing a resist unit 60 as a sheet transfer device provided with a resist roller pair 18 in a cross section orthogonal to the axial direction of the resist roller pair 18.

The resist roller pair 18 of the present embodiment is composed of a resist driving roller 18A and a resist driven roller 18B as a pair, and in addition to a function of sandwiching and transporting paper, the tip of the paper abuts on the nip portions of both rollers. In that state, a certain amount of paper is fed to form slack, which also has a function of correcting the skew of the paper. The resist roller pair 18 of the present embodiment is mounted on the drawing unit 30 in a state of being mounted on the resist unit 60.

The resist unit 60 of the present embodiment includes a resist drive roller 18A and a resist driven roller 18B constituting a resist roller pair 18, unit side plates 61A and 61B (see FIG. 6 for the unit side plate 61A on the front side in the drawing), and a unit side plate 61A. A swing guide plate 62 that is a first guide member that can be opened and closed with respect to 61B, a fixed guide plate 63 that is a second guide member fixed to unit side plates 61A and 61B, a paper detection sensor 80, a lock mechanism 70, and the like. Have.

The resist drive roller 18A is rotatably supported by two unit side plates 61A and 61B, respectively, and is rotationally driven by a resist motor 91 and a drive transmission mechanism as drive means installed in the printer main body 1. On the other hand, both ends of the resist driven roller 18B in the roller axial direction are rotatably supported by the swing guide plate 62. The gears attached to the resist driven roller 18A and the resist driven roller 18B are in mesh with each other, and the resist driven roller 18B is also rotationally driven as the resist driven roller 18A is rotationally driven. The power transmission to the resist driven roller 18B is not limited to this configuration, and for example, the resist driven roller 18B may be rotated by frictional resistance at the nip portion with the resist driven roller 18A.

The swing guide plate 62 has a hinge 62a and is rotatably supported by a stud 61a on the unit side plates 61A and 61B via the hinge 62a. As a result, the swing guide plate 62 is in a state in which the swing guide plate 62 is closed as shown in FIG. 4 and locked by the lock mechanism 70 described later (locked state), and the swing guide plate 62 is as shown in FIG. Can be in an unlocked state (unlocked state). In the locked state in which the swing guide plate 62 is closed, the resist driven roller 18B supported by the swing guide plate 62 is pressed by the resist drive roller 18A supported by the unit side plates 61A and 61B, and the resist roller The pair 18 is in a pressure contact state. On the other hand, in the unlocked state in which the rocking guide plate 62 is unlocked, the resist driven roller 18B releases the pressure on the resist drive roller 18A, so that the resist roller pair 18 is in a non-pressure contact state.

When the rocking guide plate 62 is opened during paper jam processing or the like, the rocking guide plate 62 is set to be unlocked, and the rocking guide plate 62 is rotated clockwise with the stud 61a as a fulcrum. Then, it swings from the guide position shown in FIG. 4 to the retracted position shown in FIG. As a result, the paper transport path is opened and the jam paper can be easily removed.

In the present embodiment, since the rotation fulcrum of the swing guide plate 62 is provided on the upstream side in the paper transport direction, the jam paper accumulated between the resist roller pair 18 and the secondary transfer nip is easily removed. be able to.

Further, a paper detection sensor 80 made of a reflective optical sensor is attached to the swing guide plate 62. The paper detection sensor 80 is arranged downstream of the resist roller pair 18 in the paper transport direction, and light is emitted from the paper detection sensor 80 through the opening 62b formed in the swing guide plate 62. When there is paper in the detection area (light irradiation area) of the paper detection sensor 80, the paper reflects the light of the paper detection sensor 80, and the reflected light is detected by the light receiving element of the paper detection sensor 80. As a result, the presence of paper is detected by the paper detection sensor 80.

Further, an opening hole 63a is formed in the region of the fixed guide plate 63 facing the paper detection sensor 80 (the detection region of the paper detection sensor 80). As a result, the light from the paper detection sensor 80 passes through the opening hole 63a of the fixed guide plate 63. Therefore, the light receiving element of the paper detection sensor 80 receives the reflected light from the fixed guide plate 63, and it is prevented from erroneously detecting that there is paper even though there is actually no paper.

Further, in the present embodiment, as will be described later, the lock lever shaft 71 of the lock mechanism 70 is provided on both sides of the device in the front-rear direction on the side opposite to the transport path 19 side of the fixed guide plate 63. 71b (see FIG. 6 for the shaft member 71b on the front side in the drawing) and a connecting member 74 having a concave concave portion 174 in a cross section cut parallel to the axial direction and connecting the two shaft members. Have. The concave portion 174 is provided so as to face the opening hole 63a of the fixed guide plate 63. As a result, the lock lever shaft 71 can be prevented from being within the detection distance of the paper detection sensor 80. As a result, the light receiving element of the paper detection sensor 80 receives the reflected light from the lock lever shaft 71, and it is prevented from erroneously detecting that there is paper even though there is actually no paper.

Further, the concave portion 174 may have a concave cross section cut in parallel with the axial direction (see FIG. 6), and in the present embodiment, the concave portion 174 cut in the paper transport direction as shown in FIG. The cross section of is L-shaped. Further, the present invention is not limited to this, and the concave portion 174 may have a notch shape in which only the bottom surface portion is left. Further, it is preferable that the concave portion 174 has a concave shape even in the cross section cut in the paper transport direction, because the strength of the concave portion 174 can be increased.

The paper detection sensor 80 is connected to the control unit 90, and the control unit 90 controls the drive of the resist motor 91 based on the detection result of the paper detection sensor 80. Specifically, in the present embodiment, the paper transport speed of the paper that has passed through the resist roller pair 18 is reduced to allow the paper to enter the transfer nip. Before transporting the paper toward the transfer nip, the tip of the paper is brought into contact with the resist roller pair 18 to perform skew correction, but depending on the paper type, the contact with the resist roller pair 18 is completely complete. The skew may not be corrected and the skew may remain slightly, or the contact position with respect to the resist roller pair 18 may differ depending on the paper thickness and the like. Therefore, the timing at which the center of the paper in the width direction reaches the transfer nip may vary from paper to paper.

Therefore, the control unit 90 measures the time from the start of driving the resist roller pair 18 until the paper detection sensor 80 detects the tip of the paper, and controls the deceleration timing of the paper based on the measured time. doing. When the time from the start of driving the resist roller pair 18 to the detection of the tip of the paper by the paper detection sensor 80 is shorter than the specified time, the deceleration timing of the paper transport speed is accelerated and the registration roller pair 18 is decelerated. When the time from the start of driving to the detection of the leading edge of the paper by the paper detection sensor 80 is shorter than the specified time, the deceleration timing of the paper transport speed is delayed. As a result, the paper can be conveyed to the transfer nip at a specified timing.

FIG. 6 is a cross-sectional view taken along the line AA of FIG.
The lock mechanism 70 of the present embodiment is locked in a locked state (see FIG. 6) in which the swing guide plate 62 is locked in a closed state (the resist driving roller 18A and the resist driven roller 18B constituting the resist roller pair 18 are in a pressure contact state). ) And the non-locked state in which the lock is released and the resist driving roller 18A and the resist driven roller 18B are brought into a non-pressure contact state.

In the lock mechanism 70 of the present embodiment, the lock lever shaft 71 is arranged on the front side of the device, one end is arranged on the first shaft member 71a supported by the unit side plate 61A on the front side, and the lock lever shaft 71 is arranged on the back side of the device. It has a second shaft member 71b whose one end is supported by the unit side plate 61B on the back side, and a connecting member 74 that connects the first shaft member 71a and the second shaft member 71b. A first mounting hole 171a into which the other end of the first shaft member 71a is inserted and mounted, a second mounting hole 171b into which the other end of the second shaft member 71b is inserted and mounted, and a fixing guide It has a concave portion 174 provided so as to face the opening hole 63a of the plate.

The first lock claw 72A and the lock lever 73 are fixed to the first shaft member 71a of the lock lever shaft 71. A second lock claw 72B is fixed to the second shaft member 71b. The lock lever shaft 71 is supported so as to be movable in the roller axial direction with respect to the unit side plates 61A and 61B. An urging force is applied to the lock lever shaft 71 on the front side (right side in the drawing) by an urging means such as a spring. By performing the operation of moving the lock lever 73 in the direction indicated by the reference numeral C in FIG. 6, the lock lever shaft 71 can be moved in the direction indicated by the reference numeral C in FIG. 6 against the above-mentioned urging force. As a result, the two lock claws 72A and 72B can be moved in the direction indicated by reference numeral C in FIG.

When the swing guide plate 62 is closed, as shown in FIG. 6, the tips (claw-shaped portions) of the lock claws 72A and 72B are inside the swing guide plate 62 (with the transport path 19 of the swing guide plate 62). Is on the other side). At this time, since the lock lever shaft 71 is urged in the direction opposite to the direction indicated by the reference numeral C in FIG. 6, the lock claws 72A and 72B are urged in the direction in contact with the swing guide plate 62. As a result, the tip portions (claw-shaped portions) of the lock claws 72A and 72B are caught by the swing guide plate 62, the rotation of the swing guide plate 62 in the opening direction is restricted, and the lock state is set.

When the swing guide plate 62 is opened during paper jam processing or the like, the user operates the lock lever 73 in the direction indicated by the reference numeral C in FIG. 6, so that the lock claws 72A and 72B also move in the same direction. , The hooking of the tip portions (claw-shaped portions) of the lock claws 72A and 72B with respect to the swing guide plate 62 is released. As a result, the restriction on the rotation of the swing guide plate 62 in the opening direction is released, and the rocking guide plate 62 is in an unlocked state.

In the unlocked state, the resist roller pair 18 that was in the pressure contact state becomes a non-pressure contact state, so that the distance between the axes of the resist drive roller 18A and the resist driven roller 18B that constitute the resist roller pair 18 is in the pressure contact state. Spread more than. As a result, the swing guide plate 62 that supports the resist driven roller 18B is pushed up from the unit side plates 61A and 61B. In this state, since the swing guide plate 62 is located above the tip portions (claw-shaped portion) of the lock claws 72A and 72B, the tip portion (claw-shaped portion) is located outside the swing guide plate 62. Therefore, the user stops the operation of moving the lock lever 73 in the direction indicated by the reference numeral C in FIG. 6, and the lock lever shaft 71 and the lock claws 72A and 72B are indicated in the direction opposite to the reference numeral C in FIG. Even if the lock claws 72A and 72B are moved to, the tip portions (claw-shaped portions) of the lock claws 72A and 72B are not caught by the swing guide plate 62, and the unlocked state is maintained.

When the swing guide plate 62 is closed, the swing guide plate 62 is pushed down so that the swing guide plate 62 comes into contact with the upper surface of the tip portions (claw-shaped portions) of the lock claws 72A and 72B. As shown in FIG. 6, the upper surface of the tip portions (claw-shaped portions) of the lock claws 72A and 72B has an inclined surface, and the swing guide plate 62 locks as the swing guide plate 62 moves downward. It slides on the inclined surface of the claws 72A and 72B, whereby the lock claws 72A and 72B move in the direction indicated by reference numeral C in FIG. 6 against the above-mentioned urging force. After that, when the swing guide plate 62 moves downward until the tips (claw-shaped portions) of the lock claws 72A and 72B enter the inside of the swing guide plate 62 (positioned above the swing guide plate 62), The lock lever shaft 71 and the lock claws 72A and 72B move in the direction opposite to the direction indicated by the reference numeral C in FIG. 6, and the tips (claw shape portions) of the lock claws 72A and 72B are caught by the swing guide plate 62. , The swing guide plate 62 is locked so that its rotation in the opening direction is restricted.

In the present embodiment, the lock lever shaft 71 is arranged at the same position as the arrangement position of the paper detection sensor 80 in the paper transport direction. Further, the distance Ls from the shaft members 71a and 71b of the lock lever shaft 71 to the paper detection sensor 80 is shorter than the maximum detection distance Lmax at which the paper detection sensor 80 can detect the member (Ls <Lmax). Therefore, when the lock lever shaft 71 does not have the concave portion 174, the light emitted from the paper detection sensor 80 passes through the opening hole 63a of the second guide member and is reflected by the lock lever shaft 71. Then, the reflected light is received by the light receiving element of the paper detection sensor 80. As a result, there is a risk of erroneously detecting that there is paper even though there is no paper.

Therefore, as shown in FIG. 7, it is conceivable to provide the lock lever shaft 71 on the downstream side in the paper transport direction with respect to the paper detection sensor 80 so that the lock lever shaft 71 does not face the paper detection sensor 80. However, in the configuration shown in FIG. 7, the resist unit 60 becomes large in the paper transport direction. It is also conceivable that the distance Ls from the lock lever shaft 71 to the paper detection sensor 80 is longer than the maximum detection distance Lmax of the paper detection sensor 80. However, in this case, the resist unit 60 becomes large in the vertical direction.

Further, the rocking fulcrum of the swing guide plate 62 is set on the downstream side in the paper transport direction, and the lock lever shaft 71 is provided on the upstream side in the paper transport direction so that the lock lever shaft 71 does not face the paper detection sensor 80. be able to. However, in this configuration, it becomes difficult to remove the jam paper accumulated between the resist roller pair 18 and the secondary transfer nip.

Therefore, in the present embodiment, a concave portion 174 recessed on the side opposite to the fixed guide plate 63 side is provided in the region of the fixed guide plate 63 of the lock lever shaft 71 facing the opening hole 63a, and is recessed from the paper detection sensor 80. The distance L to the bottom surface 174a of the shape portion 174 is made longer than the maximum detection distance Lmax of the paper detection sensor 80 (Lmax <L). As a result, even if the distance Ls from the lock lever shaft 71 to the paper detection sensor 80 is shorter than the maximum detection distance Lmax of the paper detection sensor 80 (Ls <Lmax), the lock lever shaft 71 is irradiated from the paper detection sensor 80. It is possible to suppress the arrival of light, and it is possible to suppress erroneous detection of the paper detection sensor 80 due to the reflected light from the lock lever shaft 71.

Further, a sheet having a low light reflectance may be attached to the bottom surface 174a of the concave portion 174. As a result, the reflected light from the lock lever shaft 71 can be further suppressed from being incident on the light receiving element of the paper detection sensor 80. Further, as compared with the case where a sheet having a low light reflectance is not attached, it is possible to suppress erroneous detection of the paper detection sensor 80 even if the bottom surface 174a of the concave portion is closer to the paper detection sensor 80. Therefore, the size of the resist unit 60 can be further reduced.

Next, attachment of the first shaft member 71a and the second shaft member 71b to the connecting member 74 will be described.
FIG. 8 is a side view showing a method of fixing the first shaft member 71a and the second shaft member 71b to the connecting member 74.
The connecting member 74 has a first mounting hole 171a into which the other end of the first shaft member 71a is inserted and mounted, and a second mounting hole 171b into which the other end of the second shaft member 71b is inserted and mounted. ing. Further, the connecting member 74 is formed with a first screw through hole 172a that is formed in a direction orthogonal to the insertion direction of the shaft member into the mounting hole and communicates with the first mounting hole 171a, and an insertion direction of the shaft member into the mounting hole. It has a second screw through hole 172b that is opened in a direction orthogonal to the second mounting hole 171b and communicates with the second mounting hole 171b.

Further, the first shaft member 71a is provided with a screw hole 173a having a screw groove on the inner peripheral surface at a position facing the first screw through hole 172a when the first shaft member 71a is inserted into the first mounting hole 171a. Has been done. Similarly, the second shaft member 71b has a screw hole 173b having a screw groove on the inner peripheral surface at a position facing the second screw through hole 172b when the second shaft member 71b is inserted into the second mounting hole 171b. It is provided.

By passing a screw through the screw through holes 172a and 172b and screwing the screw into the screw holes 173a and 173b of each shaft member, the shaft members 71a and 71b are screwed to the connecting member 74.

Further, in the present embodiment, the lock lever shaft 71 is composed of the first shaft member 71a, the second shaft member 71b, and the connecting member 74 having the concave portion 174 to form one lock lever shaft 71. The strength of the lock lever shaft 71 can be increased as compared with the case where the shaft member is provided with a concave portion by cutting a portion of the fixed guide plate 63 facing the opening hole 63a. As a result, it is possible to prevent the lock lever shaft 71 from being deformed when the user operates the lock lever shaft 71 against the urging force of the urging means such as a spring.

Further, in the present embodiment, the concave portion 174 is provided in the portion of the lock lever shaft 71 facing the opening hole 63a of the fixed guide plate 63, and the concave portion 174 penetrates the facing portion in the optical axis direction of the paper detection sensor 80. A through hole may be provided. Even with such a configuration, the lock lever shaft 71 can be prevented from being present within the maximum detection distance Lmax of the paper detection sensor 80, and erroneous detection due to the reflected light from the lock lever shaft 71 can be prevented.

What has been described above is an example, and has a unique effect in each of the following aspects.
(Aspect 1)
The first guide member such as the swing guide plate 62, the second guide member such as the fixed guide plate 63 facing the first guide member, and the first guide member and the second guide member arranged on the first guide member side. In a sheet transfer device such as a resist unit 60 having an optical sensor such as a paper detection sensor 80 that optically detects a sheet such as paper conveyed in a sheet transfer path formed between the two guides. A lock lever provided with a through hole such as an opening hole 63a in a region facing the optical sensor of the member, and arranged so that a part of the second guide member faces the through hole of the second guide member on the opposite side to the transport path side. A concave-shaped portion or a through hole is provided in a portion facing the through hole of a member such as the shaft 71.
According to this, the light emitted from the optical sensor is generated by providing a through hole such as an opening hole 63a in the region facing the optical sensor such as the paper detection sensor 80 of the second guide member such as the fixed guide plate 63. It passes through the through hole of the second guide member. As a result, erroneous detection due to reflected light from the second guide member can be suppressed.
Further, by providing a through hole in the second guide member to suppress erroneous detection due to reflected light from the second guide member, a concave portion is provided in the second guide member, and the reflected light from the second guide member is provided. The member can be arranged on the side opposite to the transport path side of the second guide member, unlike the one that suppresses the false detection due to the above.
Further, in the first aspect, a concave cross-sectional portion or a through hole is provided in a portion facing the through hole of the member such as the lock lever shaft 71 arranged on the side opposite to the transport path side of the second guide member. As a result, in the configuration in which the concave portion of the cross section is provided in the portion of the member arranged on the side opposite to the transport path side of the second guide member and facing the through hole of the second guide member, the second guide member of the above member The portion facing the through hole can be separated from the optical sensor more than the other portion of the member. This makes it possible to make the portion of the member facing the through hole of the second guide member out of the detectable range of the optical sensor. Further, in the configuration in which the through hole is provided in the portion facing the through hole of the second guide member, the light from the optical sensor that has passed through the second guide member passes through the through hole of the member. As a result, erroneous detection due to reflected light from the member arranged on the second guide member can be suppressed.

(Aspect 2)
In the first aspect, a concave portion having a concave shape such as a concave portion 174 is provided in a portion facing a through hole such as an opening hole 63a of a member such as a lock lever shaft 71 arranged on the side opposite to the transport path side of the second guide member. The maximum detection distance of an optical sensor such as the paper detection sensor 80 is Lmax, the distance from the optical sensor to a member such as the lock lever shaft 71 is Ls, and the distance from the optical sensor to the bottom surface 174a of the concave cross section. When L is set, Ls <Lmax <L is satisfied.
According to this, as described in the embodiment, the device can be made smaller by making the distance Ls from the optical sensor to the member such as the lock lever shaft 71 shorter than the maximum detection distance Lmax of the optical sensor such as the paper detection sensor 80. Can be achieved. Further, the light emitted from the optical sensor is emitted by making the distance L from the optical sensor to the bottom surface 174a of the concave portion of the cross section such as the concave portion 174 longer than the maximum detection distance Lmax of the optical sensor such as the paper detection sensor 80. However, it does not reach the bottom surface 174a of the concave cross-section portion, and it is possible to prevent the reflected light from being generated from the bottom surface 174a of the concave cross-section portion. As a result, erroneous detection due to reflected light from a member such as the lock lever shaft 71 can be suppressed.

(Aspect 3)
In aspects 1 or 2, a portion of a member such as a lock lever shaft 71 arranged on the side opposite to the transport path side of the second guide member such as the fixed guide plate 63 and facing a through hole such as an opening hole 63a of the second guide member. A sheet having a concave cross-sectional shape such as a concave cross-section portion 174 is provided on the bottom surface 174a of the concave cross-section portion and has a lower light reflectance than the bottom surface 174a.
According to this, as described in the embodiment, the reflected light from the bottom surface 174a can be further suppressed, and the false detection due to the reflected light from the member such as the lock lever shaft 71 can be further suppressed.

(Aspect 4)
In any of aspects 1 to 3, a transport roller pair such as a resist roller pair 18 is provided.
The member arranged on the side opposite to the transport path side of the second guide member is in a locked state in which the transport roller is locked between the two rollers in a pressure contact state, and is released from the lock so that the two rollers are in a non-pressure contact state. A lock shaft such as a lock lever shaft 71 for switching to the unlocked state.
According to this, as described in the embodiment, it is possible to suppress erroneous detection due to the reflected light from the lock shaft such as the lock lever shaft 71.

(Aspect 5)
In the fourth aspect, the lock shaft such as the lock lever shaft 71 is the first shaft such as the first shaft member 71a and the second shaft such as the second shaft member 71b arranged coaxially with the first shaft. It is composed of a connecting member such as a connecting member 74 that connects the shaft and the second shaft, and the connecting member is provided with a concave cross-sectional portion or a through hole.

(Aspect 6)
An image forming apparatus for forming an image on a sheet conveyed by the sheet conveying device, and the sheet conveying device according to any one of aspects 1 to 5 was used as the sheet conveying device.
According to this, it is possible to reduce the size of the device and suppress erroneous detection of the sheet.

18: Resist roller pair 18A: Resist drive roller 18B: Resist driven roller 19: Conveyance path 30: Drawer unit 60: Resist unit 61A: Unit side plate 61B: Unit side plate 61a: Stud 62: Swing guide plate 62a: Hinge 62b: Open Part 63: Fixed guide plate 63a: Opening hole 70: Lock mechanism 71: Lock lever shaft 71a: First shaft member 71b: Second shaft member 72A: First lock claw 72B: Second lock claw 73: Lock lever 74: Connection Member 80: Paper detection sensor 90: Control unit 91: Resist motor 100: Printer 171a: First mounting hole 171b: Second mounting hole 172a: First screw through hole 172b: Second screw through hole 173a: Screw hole 173b: Screw Hole 174: Concave portion 174a: Bottom surface L: Distance from bottom surface to paper detection sensor Lmax: Maximum detection distance Ls: Distance from shaft member of lock lever shaft to paper detection sensor P: Paper

Japanese Unexamined Patent Publication No. 2006-306609

Claims (6)

First guide member and
The second guide member facing the first guide member and
A sheet arranged on the first guide member side and having an optical sensor that optically detects a sheet conveyed in a sheet conveying path formed between the first guide member and the second guide member. In the transport device
A through hole is provided in the area of the second guide member facing the optical sensor.
A concave cross-sectional portion or a through hole is provided in a portion of the member arranged so that a part thereof faces the through hole of the second guide member on the side opposite to the transport path side of the second guide member. A sheet transfer device characterized by the fact that. In the sheet transport device according to claim 1,
A member arranged on the side opposite to the transport path side of the second guide member has a concave cross-sectional portion at a portion facing the through hole of the second guide member.
The maximum detection distance of the optical sensor is Lmax,
The distance from the optical sensor to the member is Ls,
When the distance from the optical sensor to the bottom surface of the concave cross-section is L.
Ls <Lmax <L
A sheet transfer device characterized by satisfying the above conditions. In the sheet transport device according to claim 1 or 2.
A member arranged on the side opposite to the transport path side of the second guide member has a concave cross-sectional portion at a portion facing the through hole of the second guide member.
A sheet transporting device characterized in that a sheet having a light reflectance lower than that of the bottom surface is provided on the bottom surface of the concave cross-sectional portion. In the sheet transport device according to any one of claims 1 to 3.
Has a pair of transport rollers
The members arranged on the side opposite to the transport path side of the second guide member are in a locked state in which the two rollers of the transport roller pair are locked in a pressure-welded state, and in a locked state in which the lock is released and the two rollers are not pressure-welded. A sheet transfer device characterized by being a lock shaft for switching to a non-locked state. In the sheet transport device according to claim 4,
The lock shaft includes a first shaft, a second shaft coaxially arranged with the first shaft, and a connecting member connecting the first shaft and the second shaft.
A sheet transfer device characterized in that the connecting member is formed with the concave cross-sectional portion or the through hole. An image forming apparatus that forms an image on a sheet conveyed by a sheet conveying device.
An image forming apparatus according to any one of claims 1 to 5, wherein the sheet conveying device according to any one of claims 1 to 5 is used as the sheet conveying device.

Images