JP6535255B2 - Medium detection device and image forming apparatus - Google Patents

Description

  The present invention relates to a medium detection apparatus and an image forming apparatus, and is suitably applied to, for example, an electrophotographic printer.

  Conventionally, as an image forming apparatus, for example, a toner image is generated by an exposure device, and the intermediate image transfer belt is caused to carry the toner image, and a transport unit including rollers transports a sheet as a medium along a transport path. There is a printer which prints an image by transferring a toner image from an intermediate transfer belt to a sheet and fixing the sheet by applying heat or pressure.

  When printing an image on a sheet, the image forming apparatus may transfer a toner image from the intermediate transfer belt after detecting, for example, the leading end position of the sheet. The image forming apparatus may print an image on sheets of various widths, and the positions of these sheets also need to be detected correctly.

  Therefore, in the image forming apparatus, for example, a carriage movable along the width direction is provided on one side of the sheet conveyance path, and a reflection sensor including a light emitting element and a light receiving element is mounted on the carriage. There has been proposed one that detects the position of the leading edge of a sheet of paper (see, for example, Patent Document 1).

Japanese Utility Model Application Publication 6-7950 (FIG. 1)

  The image forming apparatus may print an image on a so-called label sheet. This label sheet has, for example, a configuration in which a plurality of label sheet pieces having a small area and a high tackiness on the back surface are pasted along a sheet conveyance direction with respect to a base sheet having a large area and a high removability on the surface.

  In this label sheet, it is necessary to print an image in alignment with the position of the label sheet. Therefore, in the image forming apparatus, the light emitting element is disposed on one side of the label sheet and the light receiving element is disposed on the other side to constitute a transmission type sensor, and light is generated by only the mount and the mount and the label sheet By utilizing the fact that the transmittance of the sheet is different, it is possible to detect the tip position of the label sheet.

  In addition, as this label paper, those of various widths are used as well as ordinary paper. Therefore, in the image forming apparatus, it is conceivable to provide carriages movable in the width direction on both sides of the sheet conveyance path, and mount the light emitting element and the light receiving element on these carriages. In this case, in the image forming apparatus, when moving the carriages respectively provided on both sides of the conveyance path in the width direction, it is necessary to perform position adjustment so that the positions of the light emitting element and the light receiving element are aligned with each other. Therefore, in the image forming apparatus, it is conceivable to incorporate an interlocking mechanism that interlocks the movements of the carriages in the width direction with each other.

  By the way, in the image forming apparatus, when jamming of the sheet occurs in the sheet conveyance path, or foreign matter such as paper dust may adhere to the surface of the light receiving element, a maintenance operation is required to remove these. In this maintenance operation, in the image forming apparatus, the opening and closing operation of the conveyance path is performed such that both sides of the conveyance path in the conveyance unit are temporarily separated from each other and returned to their original state after the maintenance operation.

  However, in the image forming apparatus, if the interlocking of the respective carriages in the interlocking mechanism is temporarily released when the opening / closing operation is performed in the conveyance unit, the detection accuracy is lowered. Further, in the image forming apparatus, in order to re-set the positions of the carriages with each other, an adjustment operation is required, and there is a problem that a great deal of labor is required.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose a medium detection apparatus and an image forming apparatus capable of achieving both the maintenance of the medium detection accuracy and the maintenance of the workability in maintenance.

In order to solve the problems, in the medium detection device according to the present invention, the first main body portion disposed on one side of the conveyance path for conveying the medium along the predetermined conveyance direction, and the other body side of the conveyance path A second body portion, and a body rotation portion configured to rotate the first body portion relative to the second body portion around a body rotation axis parallel to the one surface and along a cross direction crossing the transport direction; The first screw shaft is formed such that the central axis extends in the cross direction, a thread groove is formed on the circumferential side, and the first main body rotatably supports the first screw shaft about the central axis, and the central axis extends in the cross direction A screw groove is formed on the circumferential side surface, and has a second screw shaft rotatably supported centering on the central axis by the second main body portion, and a first insertion hole through which the first screw shaft is inserted, the first insertion The screw of the first screw shaft on the inner circumferential surface of the hole A screw groove is formed to be screwed into the groove, and has a first carriage that moves in a cross direction as the first screw shaft rotates, and a second insertion hole through which the second screw shaft is inserted, the second insertion hole And a second carriage that moves in a cross direction with rotation of the second screw shaft, and a first carriage and a second carriage. A transmitting element provided on one side for transmitting light or an electromagnetic wave to the transport path, a receiving element provided on the other of the first carriage and the second carriage for receiving the light or the electromagnetic wave from the transport path An interlocking portion that interlocks the rotation of the first screw shaft and the rotation of the second screw shaft is provided via the intermediary rotating body that rotates around the intermediary central axis that coincides with the angle.

  Further, in the image forming apparatus of the present invention, development is performed according to the above-described medium detection device, a control unit that determines the position of the medium based on the detection result by the medium detection device, and the position of the medium determined by the control unit. An image forming section for transferring and fixing an image formed by the agent is provided.

  The present invention can move both in the cross direction while maintaining the relative position between the transmitting element and the receiving element, and also when the second main body is rotated with respect to the first main body. , Can maintain its relative position.

  According to the present invention, it is possible to realize a medium detection device and an image forming apparatus capable of achieving both the maintenance of the accuracy of detecting the medium and the securing of the workability in the maintenance.

FIG. 1 is a schematic diagram showing the configuration of an image forming apparatus. FIG. 2 is a schematic diagram illustrating the configuration of a sheet. It is an approximate line perspective view showing composition of a conveyance main part. It is a basic diagram which shows the structure of a conveyance main-body part. It is a schematic diagram which shows the left view and sectional drawing of a conveyance main-body part. It is an approximate line perspective view showing composition of a conveyance main part. It is a schematic diagram which shows opening and closing of a conveyance main-body part. FIG. 6 is a schematic diagram showing the configuration of a sheet detection sensor unit. It is a basic diagram which shows opening and closing of the structure of an interlocking | linkage part, and a main body upper part. It is an approximate line perspective view showing composition of an upper sensor part and a lower sensor part. FIG. 6 is a schematic perspective view showing the engagement of the lock lever in the closed state. It is a schematic diagram which shows rotation and engagement of a lock lever.

  Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described using the drawings.

[1. First embodiment]
[1-1. Configuration of image forming apparatus]
As shown in FIG. 1, the image forming apparatus 1 according to the first embodiment is configured as an electrophotographic printer, and can print a desired color image on a long sheet P, for example. ing. The image forming apparatus 1 is roughly divided into a main unit 2 that performs printing processing, a conveyance cutting unit 3 that conveys and cuts the sheet P, and a roll feeder unit 4 that supplies the sheet P. Further, inside the main body 2, a control unit 5 is provided which performs overall control of the whole.

  The control unit 5 is configured mainly of a CPU (Central Processing Unit) not shown, and reads out and executes a predetermined program from a ROM (Read Only Memory) or a flash memory etc. not shown to execute various processing related to printing. I do. The control unit 5 internally includes a storage unit such as a random access memory (RAM), a hard disk drive, a flash memory, etc., and stores various information in the storage unit.

  The control unit 5 is wirelessly or wiredly connected to a host apparatus (not shown) such as a personal computer via a communication processing unit (not shown). The control unit 5 starts printing processing for forming an image on the surface of the sheet P when image data representing an image to be printed is given from the host apparatus and printing of the image data is instructed.

  For convenience of explanation, in the following, the roll feeder unit 4 side is the front side, the main body 2 side is the rear side, the near side of the sheet in FIG. 1 is the left side, the back side is the right side, and the upper side and the lower side are defined. I will explain.

  The sheet P as a medium is wound so as to wrap around the circumferential side surface of a core material (not shown) along the left-right direction and has a roll shape (hereinafter, this portion is referred to as a roll portion PR). One end is pulled away from the outermost circumference, and travels along a conveyance path described later. As shown in FIGS. 2A and 2B, the sheet P is a so-called label sheet, and is configured of a mount PM and a plurality of label sheet pieces PL. The backing sheet PM is elongated along the traveling direction, and the removability of the surface is enhanced. The label sheet PL has a relatively small rectangular shape and has enhanced adhesion on the back surface, and is attached to the front surface of the backing sheet PM at predetermined intervals along the traveling direction.

  The roll feeder unit 4 (FIG. 1) is mounted on the front side of the transport cutting unit 3 by the mounting arm 11, and the roll holder 12 provided on the front side rotatably holds the roll portion PR of the sheet P. There is. When one end of the sheet P is pulled away from the outermost periphery of the roll portion PR, the sheet P is pulled back and downward along the arrow E1.

  The conveyance cutting unit 3 includes a guide roller 21 and a conveyance unit 22 in the housing 20. The guide roller 21 is provided on the lower side on the front side of the housing 20 and is formed in a cylindrical shape with the central axis along the left-right direction, and can rotate around the central axis with respect to the housing 20 It is supported by The guide roller 21 guides the sheet P pulled out of the roll portion PR while bringing the sheet P into contact with the lower side portion of the circumferential side, advances the sheet P obliquely rearward and upward along the arrow E2, and delivers it to the transport portion 22.

  A conveyance path 22Y is formed in the conveyance section 22 along the front-rear direction, and along the conveyance path 22Y, a conveyance roller pair 23, a sheet detection sensor section 26, and a sheet cutting section 28 are provided in order from the front. There is. The transport roller pair 23 is configured by transport rollers 24 and 25 disposed so as to sandwich the transport path 22Y from above and below.

  The conveyance roller 24 is disposed below the conveyance path 22Y, is formed in a cylindrical shape with a central axis along the left-right direction, and rotates counterclockwise in FIG. 1 by a driving force supplied from a conveyance motor (not shown). To rotate. The conveyance roller 25 is disposed on the lower side of the conveyance path 22Y, is formed in a cylindrical shape similar to the conveyance roller 24, and can be freely rotated and biased downward. Therefore, when the sheet P advances along the transport path 22Y, the transport roller pair 23 sandwiches the sheet P between the transport rollers 24 and 25 and transmits the rotational driving force of the transport roller 24 to the sheet P. Thus, the sheet P is advanced backward.

  The sheet detection sensor unit 26 has a transmission sensor and a reflection sensor, and detects the presence or absence of the sheet P, the leading end position of the label sheet PL (FIG. 2) on the sheet P, etc. using reflection or transmission of light. And notifies the control unit 5 of the obtained detection result. The sheet cutting unit 28 incorporates therein a cutter for cutting the sheet P, a conveyance roller pair for conveying the sheet P, and the like. The sheet cutting unit 28 cuts the sheet P based on the control of the control unit 5 in accordance with the position of the label sheet PL detected by the sheet detection sensor unit 26 or the like.

  Further, the transport unit 22 transports the sheet P along the transport path 22Y by the transport roller pair 23 and the transport roller pair in the sheet cutting unit 28, and advances the sheet P into the rear main body 2.

  The main body portion 2 is disposed on the upper side in the interior of the housing 30 formed in a rectangular parallelepiped shape so that the plurality of primary transfer portions 31 are aligned along the front-rear direction. Each primary transfer portion 31 corresponds to each color such as yellow (Y), magenta (M), cyan (C), black (K) and white (W), for example.

  The primary transfer portions 31 are different only in color, and all are configured in the same manner. The primary transfer portion 31 includes a toner cartridge, an LED (Light Emitting Diode) head, a photosensitive drum, and the like, and the toner image based on the image data supplied from the control unit 5 is used as the circumferential side surface of the photosensitive drum. To the intermediate transfer belt 41 of the intermediate transfer section 32.

  Inside the housing 30, the intermediate transfer portion 32 is disposed below the primary transfer portion 31, and further below the intermediate transfer portion 32, that is, approximately in the vertical center of the housing 30. In the portion, the transport path 30Y for the sheet P is formed along the front-rear direction. Further, in the housing 30, along the transport path 30Y, the central transport portion 33, the secondary transfer portion 34, the fixing portion 35, and the rear transport portion 36 are sequentially disposed from the front to the rear.

  The intermediate transfer unit 32 includes an intermediate transfer belt 41 and a plurality of belt rollers 42 for causing the intermediate transfer belt 41 to travel. Each belt roller 42 is formed in a cylindrical shape in which the central axis is in the left-right direction, and is rotated by a driving force supplied from a belt driving motor (not shown). The intermediate transfer belt 41 is an endless belt made of a flexible material, and surrounds the plurality of belt rollers 42 and the backup roller 46 (described in detail later) of the secondary transfer portion 34. It is stretched as it is. The intermediate transfer unit 32 causes the intermediate transfer belt 41 to travel by the rotation of each of the belt rollers 42 and the backup roller 46, and causes the toner image transferred from the primary transfer unit 31 to reach the secondary transfer unit 34.

  The central conveyance unit 33 includes three pairs of conveyance rollers 43A, 43B and 43C discretely disposed along the conveyance path 30Y, and a detection sensor group 44 formed of a plurality of detection sensors. Conveying roller pairs 43A, 43B, and 43C are configured in the same manner as the conveying roller pair 23 of the conveyance cutting unit 3, and rotate in a predetermined direction by the driving force supplied from the conveyance motor (not shown). The sheet P is conveyed backward along the line.

  The detection sensor group 44 is a transmission sensor, a reflection sensor, etc. similar to the paper detection sensor unit 26 of the conveyance / cutting unit 3, and the presence or absence of the paper P and the label paper piece PL on the paper P The tip position and the like shown in FIG. 2) are detected, and the obtained detection result is notified to the control unit 5. The control unit 5 controls the conveyance roller pairs 43A, 43B, and 43C according to the detection result supplied, to thereby position the label sheet PL on the sheet P by the position of the toner image carried on the intermediate transfer belt 41. To reach the secondary transfer portion 34.

  The secondary transfer portion 34 includes a secondary transfer roller 45 and a backup roller 46 disposed on the lower side and the upper side of the conveyance path 30Y. Each of the secondary transfer roller 45 and the backup roller 46 is formed in a cylindrical shape with the central axis along the left and right direction, and rotates in a predetermined direction by the driving force from a motor (not shown). Further, a predetermined bias voltage is applied to the secondary transfer roller 45. The secondary transfer portion 34 rotates the secondary transfer roller 45 and the backup roller 46 in a state where the intermediate transfer belt 41 and the sheet P are sandwiched therebetween, whereby the toner image is transferred from the intermediate transfer belt 41 to the sheet P. Transfer to

  The fixing unit 35 includes fixing rollers 47 and 48 disposed on the lower side and the upper side of the conveyance path 30Y, respectively. Each of the fixing rollers 47 and 48 is formed in a cylindrical shape in which the central axis is in the left-right direction, and rotates in a predetermined direction by a driving force from a motor (not shown). Each of the fixing rollers 47 and 48 has a heater provided therein. The fixing unit 35 heats the fixing rollers 47 and 48 and rotates the fixing rollers 47 in a predetermined direction under the control of the control unit 5 to apply heat and pressure to the sheet P to fix the toner image. Deliver to the transport unit 36. As a result, an image based on the image data is formed on the sheet P.

  The rear conveyance unit 36 conveys the sheet P rearward by rotating the conveyance rollers of the conveyance roller pair disposed so as to sandwich the conveyance path 30Y from above and below. Incidentally, the sheet P discharged rearward from the main unit 2 is taken up by a sheet winding unit (not shown) disposed on the rear side of the main unit 2.

[1-2. Configuration of Central Transport Unit]
The central conveyance portion 33 is roughly divided into the front upper portion, and a conveyance front upper portion 33F constituting the upper conveyance roller and its peripheral portion of the conveyance roller pair 43A, and the conveyance main portion 33M occupying the other portion It is composed of

  3A is a perspective view, FIG. 4 is a plan view, FIG. 5 is a left side view and a cross-sectional view of a part thereof, and FIG. 6 is a schematic exploded perspective view of a part thereof. As schematically shown, the lower part of the conveyance main body 33ML below the conveyance path 30Y and the upper part of the conveyance main body 33MU above the conveyance path 30Y are included. For the convenience of explanation, some parts are simplified or omitted in each drawing.

[1-2-1. Configuration of lower part of transport main body]
The conveyance main body lower portion 33ML (FIG. 3) is configured such that various components are sandwiched between the lower left side plate 51L and the lower right side plate 51R, and a rectangular parallelepiped which is short in the vertical direction as a whole is formed. The lower left side plate 51L is generally in the form of a rectangular plate which is thin in the left-right direction and long in the front-rear direction, the upper end vicinity of the rear side protrudes rearward, and the rear end vicinity of the upper side protrudes upward.

  In the lower left side plate 51L (FIG. 6), a rotational hole 51H1 having a round hole penetrating in the left and right direction is formed near the rear upper end, and a lower screw shaft hole 51H2 is formed below the rotational hole 51H1. Further, an operation knob hole 51H3 is bored in front of the rotation hole 51H1. The lower right side plate 51R is configured the same as the lower left side plate 51L except for the operation knob hole 51H3.

  Lower conveyance rollers 43AL, 43BL and 43CL of the conveyance roller pairs 43A, 43B and 43C are arranged between the lower left side plate 51L and the lower right side plate 51R so as to be spaced in the front-rear direction. Further, a guide member or the like for guiding the sheet P is attached between the lower left side plate 51L and the lower right side plate 51R and at a portion other than the transport rollers 43AL, 43BL and 43CL.

  The lower screw shaft 52 is inserted through the lower screw shaft hole 51H2 of the lower left side plate 51L and the lower right side plate 51R. The lower screw shaft 52 is formed in an elongated cylindrical shape in which the central axis extends in the left-right direction, and a spiral groove (i.e., a screw groove) is incised on the circumferential side surface thereof.

  The lower carriage 53, the lower interlocking gear 54, and the knob interlocking gear 55 are inserted through the lower screw shaft 52 as the first screw shaft. As shown in FIGS. 5C and 6, the lower carriage 53 as the first carriage is formed in a rectangular parallelepiped shape sufficiently smaller than the lower transport main body 33ML as a whole. In the vicinity of the rear end of the lower carriage 53, a through hole 53H penetrating in the left-right direction is bored. The through hole 53H has a spiral groove (i.e., a screw groove) cut on the inner circumferential side surface, and is screwed with the screw groove of the lower screw shaft 52.

  In the vicinity of the center in the vertical direction on the front surface of the lower carriage 53, a guide groove 53D extending in the left-right direction is formed. On the other hand, a rear side plate 56 is provided in front of the lower carriage 53 so as to connect the lower left side plate 51L and the lower right side plate 51R. On the rear surface of the rear side plate 56, a guide rail 56R extending in the left-right direction is erected toward the rear.

  When the lower carriage 53 is assembled to the lower transport body lower portion 33ML, the lower screw shaft 52 is inserted through the through hole 53H and the guide rail 56R is inserted into the guide groove 53D to vertically move the lower transport lower portion 33ML. Movement in the back and forth direction is restricted. At this time, the lower carriage 53 has its upper surface positioned slightly lower than the transport path 30Y. When the lower screw shaft 52 is rotated in either direction, the lower carriage 53 has the screw groove mutually screwed with the through hole 53H, whereby the lower screw shaft 52 and the guide rail 56R are engaged. Move along the left or right direction.

  Furthermore, in the lower carriage 53, a reflection sensor 57 and a light receiving element 58, which are a part of the detection sensor group 44 (FIG. 1), are respectively incorporated at the rear and front positions on the upper side. The reflection sensor 57 incorporates a light emitting element and a light receiving element, emits light upward from the light emitting element and receives light traveling from above by the light receiving element, and controls the light reception result by the light receiving element. Notify Part 5 (FIG. 1). The light receiving element 58 as a receiving element receives light from above and notifies the control unit 5 of the obtained light reception result.

  In the lower carriage 53, a positioning hole 53J penetrating in the vertical direction is formed near the right end. The alignment hole 53J is a round hole having a relatively small hole diameter, and the distance between the center point thereof and the light receiving center point of the light receiving element 58 is adjusted to a predetermined distance.

  Further, a lower guide plate 59 is disposed between the upper surface of the lower carriage 53 and the transport path 30Y. The lower guide plate 59 is transparent at least at a position immediately above the reflection sensor 57 and immediately above the light receiving element 58, so that foreign matter such as paper dust and dust is reflected without inhibiting the progress of light. 57 and the light receiving element 58 can be prevented from adhering. Incidentally, the lower guide plate 59 is provided with a scale or a number indicating relative position at predetermined intervals along the left-right direction. The user can easily adjust the position of the sheet P to a suitable position by moving the lower carriage 53 with reference to the scale and the number attached to the lower guide plate 59.

  The lower interlocking gear 54 is formed in a disk shape with the central axis oriented in the left-right direction, and is a gear (gear) in which teeth are formed on the circumferential side surface. The lower interlocking gear 54 has an insertion hole 54H at its center, and when the lower screw shaft 52 is inserted into the insertion hole 54H, the lower interlocking gear 54 is positioned adjacent to the right side (ie, the inner side) of the lower left side plate 51L. And fixed to the lower screw shaft 52 and integrally rotate.

  The knob interlocking gear 55 is a gear similar to the lower interlocking gear 54, and an insertion hole 55H is bored at the center. The knob interlocking gear 55 is fixed to the lower screw shaft 52 by inserting the lower screw shaft 52 into the insertion hole 55H at a position adjacent to the left side (i.e., the outer side) of the lower left side plate 51L. Do.

  As described above, the lower screw shaft 52 is inserted into the lower screw shaft hole 51H2 of the lower left side plate 51L and the lower right side plate 51R, and integrally rotates with the lower interlocking gear 54 and the knob interlocking gear 55. It is made to move in the direction.

  Furthermore, the operation knob shaft 60 is inserted into the operation knob hole 51H3 of the lower left side plate 51L. The operation knob shaft 60 is formed in a thin cylindrical shape whose central axis is in the left-right direction, and the length in the left-right direction is also relatively short. The operation knob shaft 60 is attached to the lower left side plate 51L so as to protrude in the left direction. The operation knob 61 is inserted into the left side of the operation knob shaft 60.

  The operation knob 61 is formed in a thin disc shape in the left-right direction, and the radius thereof is sufficiently larger than the knob interlocking gear 55. Like the knob interlocking gear 55 and the like, the operation knob 61 is a gear (gear) in which teeth are formed on the circumferential side surface, and in the state of being inserted into the operation knob shaft 60 Engage with your teeth. Therefore, when the operation knob 61 is rotated by the operation of the user, the lower transport main body 33ML can rotate the lower screw shaft 52 and the lower interlock gear 54 via the knob interlock gear 55.

  Further, a lever shaft hole 51H4 is bored in front of and below the operation knob hole 51H3 in the lower left side plate 51L (FIG. 3A). The pivot shaft 65 is inserted into the lever shaft hole 51H4. The rotation shaft 65 is formed in a short cylindrical shape in which the central axis is in the left-right direction, and is configured to freely rotate with respect to the lower left side plate 51L. The control lever 66 and the lock claw 67 (FIG. 3B) are fixed to the left side (outside) and the right side (inner side) of the lower left side plate 51L of the pivot shaft 65, respectively.

  The lock claw 67 has an inclined surface such that the upper rear portion is obliquely cut off, and the lower side thereof is formed in a claw shape by being notched forward. The lock claw 67 is urged counterclockwise as viewed from the left by the spring 68 and abuts against the stopper 69 attached to the lower left side plate 51L, as shown in FIG. 3B. It is stationary.

1-2-2. Configuration of upper part of transport main body]
On the other hand, the transport main body upper portion 33MU (FIG. 3A) has a configuration in which various components are sandwiched between the upper left side plate 71L and the upper right side plate 71R, and a rectangular parallelepiped short in the vertical direction as a whole is formed. There is. The upper transport body upper portion 33MU has a length in the front-rear direction of about 2/3, a length in the vertical direction of about 1⁄2, and a length in the left-right direction slightly smaller than the lower transport body lower portion 33ML. It is short.

  The upper left side plate 71L is generally in the form of a rectangular plate which is thin in the left-right direction and long in the front-rear direction, the rear upper side portion is cut off obliquely, and the vicinity of the rear end of the lower side protrudes downward. In the upper left side plate 71L (FIG. 6), a rotation hole 71H1 formed by a round hole penetrating in the left and right direction is formed near the rear lower end, and an upper screw shaft hole 71H2 is formed in front of and above the rotation hole 71H1. It is done. The upper right side plate 71R is configured in the same manner as the upper left side plate 71L.

  The upper transport rollers 43BU and 43CU of the transport roller pairs 43B and 43C are arranged between the upper left side plate 71L and the upper right side plate 71R to be spaced apart in the front-rear direction. Further, a guide member or the like for guiding the sheet P is attached between the upper left side plate 71L and the upper right side plate 71R and at portions other than the transport rollers 43BU and 43CU.

  The upper screw shaft 72 is inserted through the upper screw shaft hole 71H2 of the upper left side plate 71L and the upper right side plate 71R. The upper screw shaft 72 as the second screw shaft is configured substantially the same as the lower screw shaft 52, and a thread groove is cut on the circumferential side surface.

  An upper carriage 73 and an upper interlocking gear 74 are inserted into the upper screw shaft 72. As shown in FIGS. 5C and 6, the upper carriage 73 as the second carriage is generally configured in a rectangular shape sufficiently smaller than the upper transport main body 33MU as a whole, and similar to the upper left side plate 71L and the like, the rear upper side The part is cut off diagonally. In the vicinity of the rear end of the upper carriage 73, a through hole 73H penetrating in the left-right direction is bored. Similar to the through holes 53 H of the lower carriage 53, the through holes 73 H have a spiral groove (i.e., a screw groove) cut in on the inner circumferential side, and screw with the screw groove of the upper screw shaft 72.

  In the vicinity of the center of the front surface of the upper carriage 73 in the vertical direction, a guide projection 73G is provided so as to project rearward. On the other hand, a rear side plate 76 is provided in front of the upper carriage 73 so as to connect the upper left side plate 71L and the upper right side plate 71R. In the rear surface of the rear side plate 76, a guide groove 76D extending in the left-right direction is formed.

  When the upper carriage 73 is assembled to the upper transport body portion 33MU, the upper screw shaft 72 is inserted through the through hole 73H, and the guide projection 73G is inserted into the guide groove 76D of the rear side plate 76, thereby the upper transport body upper portion. The movement in the vertical direction and the longitudinal direction with respect to the MU is restricted. At this time, the upper carriage 73 positions its lower surface slightly above the transport path 30Y. Similarly to the lower carriage 53, when the upper screw shaft 72 is rotated in any direction, the upper carriage 73 has the screw groove mutually screwed with the through hole 73H, thereby It moves leftward or rightward along the screw shaft 72 and the guide groove 76D.

  Furthermore, in the upper carriage 73, a light emitting element 78 which is a part of the detection sensor group 44 (FIG. 1) is incorporated near the center on the lower side. The light emitting element 78 as a light emitting element emits light downward. The light emitting element 78 emits light to the sheet P conveyed on the conveyance path 30Y in combination with the light receiving element 58 incorporated in the lower carriage 53, and serves as a transmission type sensor that receives the light transmitted through the sheet P. It is supposed to work.

  Further, similarly to the lower carriage 53, the upper carriage 73 is provided with a positioning hole 73J penetrating in the vertical direction in the vicinity of the right end. Similar to the alignment hole 53J, the alignment hole 73J is a round hole having a relatively small hole diameter, and the distance between the central point thereof and the light emission central point of the light emitting element 78 is adjusted to a predetermined distance equivalent to the lower carriage 53. ing.

  Incidentally, an upper guide plate 79 is disposed between the lower surface of the upper carriage 73 and the conveyance path 30Y. The upper guide plate 79 is transparent at least at a position immediately above the light emitting element 78, and as in the case of the lower guide plate 59, foreign matter such as paper dust and dust does not inhibit the progress of light. It is possible to prevent adhesion to the light emitting element 78.

  The upper interlocking gear 74 as the second gear is a gear (gear) similar to the lower interlocking gear 54, and an insertion hole 74H is formed at the center. When the upper screw shaft 72 is inserted into the insertion hole 74H, the upper interlocking gear 74 is positioned adjacent to the left side (i.e., the outer side) of the upper left side plate 71L and is fixed to the upper screw shaft 72 to be integrated. Rotate.

  Thus, the upper screw shaft 72 is inserted into the upper screw shaft hole 71H2 of the upper left side plate 71L and the upper right side plate 71R and rotates integrally with the upper interlocking gear 74, and at this time, the upper carriage 73 is moved in the left and right direction. It has become.

  Further, on the right side (inner side) of the upper left side plate 71L, a lock post (not shown) is provided at a position corresponding to the lock claw 67 of the lower part 33ML of the transport main body. The upper transport body upper portion 33MU is biased upward by a spring (not shown) with respect to the lower transport body lower portion 33ML.

1-2-3. Opening and closing the transport body]
As shown in FIG. 6, in the vicinity of the left rear end, the conveyance main body 33M is provided in the rotation hole 51H1 formed in the lower left side plate 51L of the conveyance main body lower portion 33ML and the upper left side plate 71L of the conveyance main body upper portion 33MU. The left pivoting shaft 81L is inserted through the pivoting hole 71H1 formed. The left pivoting shaft 81L has a short cylindrical shape in which the central axis is in the left-right direction, and can freely pivot with respect to any of the pivoting holes 51H1 and 71H1.

  Further, also near the rear end on the right side, the transport main body 33M is pivoted in the rotation hole 51H1 bored in the lower right side plate 51R of the transport body lower portion 33ML and in the upper right side 71R of the transport body upper portion 33MU. The right turning shaft 81R is inserted into the hole 71H1. The right turning shaft 81R, like the left turning shaft 81L, has a short cylindrical shape with the central axis along the left and right direction, and can freely turn to any of the turning holes 51H1 and 71H1. . Incidentally, the central axis of the right pivot shaft 81R is located on the extension of the central axis of the left pivot shaft 81L.

  With such a configuration, the transport main body 33M transports the left transport shaft 81L and the right pivot 81R (hereinafter collectively referred to as a pivot shaft 81) as a transport center relative to the transport lower portion 33ML. The upper body 33MU can be turned. As a result, as shown in FIG. 3A, the conveyance main body 33M is in a state in which the lower surface of the upper conveyance main body 33MU is opposed to the upper surface of the lower conveyance main body 33ML (hereinafter referred to as a closed state); And the lower surface of the upper transfer body portion 33MU is pulled away from the upper surface of the lower transfer body portion 33ML (hereinafter referred to as an open state).

  Specifically, in the transport body 33M, in the closed state, the closed state is maintained by the lock claws 67 of the transport lower portion 33ML engaging with the lock posts (not shown) of the transport upper portion 33MU. When the forward force is applied to the control lever 66 in the closed state, the transport body 33M rotates with the lock claw 67 to release the engagement with the lock post, and the spring causes the upper portion of the transport body to move. 33MU is turned upward to be open.

  Further, when the upper transport body upper portion 33MU is pivoted downward in the open state, the transport main body portion 33M brings the lock post of the upper transport body upper portion 33MU into contact with the inclined surface of the lock claw 67 and slides on the inclined surface In particular, after being pivoted forward, by entering the lower side of the claw shape, the lock claw 67 is engaged again to return to the closed state.

  Further, an intermediary gear 82 is provided in the vicinity of the left rear end of the transport main body 33M. The intermediary gear 82 is a gear similar to the lower interlocking gear 54 and the upper interlocking gear 74, and an insertion hole 82H is formed at the center. Incidentally, the intermediate gear 82 has a radius larger than that of the lower interlocking gear 54 and the upper interlocking gear 74.

  The intermediate gear 82 is incorporated in the transport main body 33M such that the left rotation shaft 81L is inserted into the insertion hole 82H, and can freely rotate with respect to the left rotation shaft 81L. . Furthermore, as shown in FIG. 5B, when the intermediate gear 82 is inserted into the left pivot shaft 81L, the intermediate gear 82 meshes with the lower interlocking gear 54 and the upper interlocking gear 74 in the closed state.

  Therefore, for example, when the lower interlocking gear 54 rotates integrally with the lower screw shaft 52 in the closed state, the intermediary gear 82 is rotated by transmitting the driving force from the lower interlocking gear 54, and is driven to the upper interlocking gear 74. The force can be transmitted to rotate, and the upper screw shaft 72 integral with the upper interlocking gear 74 can also be rotated.

  Here, the lower interlocking gear 54 and the upper interlocking gear 74 have the same radius as each other, and the shape and the number of formed teeth are also equivalent. The lower screw shaft 52 and the upper screw shaft 72 have the same pitch of screw grooves, that is, the same number and diameter of grooves cut per unit length in the left-right direction along the rotation axis. For this reason, the conveyance main body 33M interlocks the lower carriage 53 and the upper carriage 73 simultaneously in the same direction and by the same distance by meshing the lower interlocking gear 54 and the upper interlocking gear 74 with the intermediary gear 82. It can be done. Hereinafter, the lower interlocking gear 54, the upper interlocking gear 74, and the intermediary gear 82 are collectively referred to as the interlocking portion 80.

  By the way, in the conveyance main body 33M, in the assembling operation and the adjustment operation before shipment, the light receiving and aligning operation for aligning the mutual positions of the light emitting element 78 and the light receiving element 58 forming the transmission type sensor To be done. In this light receiving and emitting alignment operation, the lower interlocking gear 54 is first moved to the right with respect to the lower screw shaft 52 by the operator or the like, and the meshing between the lower interlocking gear 54 and the intermediary gear 82 is temporarily released. . Thus, the lower carriage 53 and the upper carriage 73 can be moved in the lateral direction independently of each other in the transport main body 33M.

  Subsequently, in the transport main body portion 33M, the alignment hole 53J of the upper carriage 73 and the alignment hole 53J of the lower carriage 53 are penetrated in a state where the positions of the upper carriage 73 and the lower carriage 53 in the horizontal direction are substantially aligned. An alignment pin (not shown) elongated in the vertical direction is inserted. Thus, the transport body 33M can position the light reception center point of the light receiving element 58 of the lower carriage 53 directly below the light emission center point of the light emitting element 78 of the upper carriage 73.

  Thereafter, in the transport body 33M, the lower interlocking gear 54 is moved in the left direction to restore the engagement with the intermediate gear 82, and the alignment pin is pulled out. Thereby, the transport main body 33M can rotate the lower screw shaft 52 and the upper screw shaft 72 equally when the operation knob 61 is rotated by the user or the like, and the lower carriage 53 and the upper carriage 73 can be turned leftward or The same distance can be moved in the right direction. That is, the transport main body 33M can move both of the light emitting element 78 and the light receiving element 58, which form the transmission type sensor, in the left and right direction while keeping the mutual position constant.

  Here, as shown in FIG. 7A, a point representing the center of rotation of the transport body upper portion 33MU with respect to the transport body lower portion 33ML and representing the center of the pivot shaft 81 is a point P, and the lower screw shaft 52 and the lower interlocking gear A point representing the center of rotation of 54 is a point Q, and a point representing the center of rotation of the upper screw shaft 72 and the upper interlocking gear 74 is a point R. Further, the distance between the points PQ is taken as a distance LPQ, and the distance between the points PR is taken as a distance LPR. The positions of the respective holes in the lower left side plate 51L and the upper left side plate 71L are not changed without further explanation.

  For this reason, as shown in FIG. 7 (B) corresponding to FIG. 7 (A), in the transport body 33M, regardless of the rotation angle of the transport body upper portion 33MU with respect to the transport body lower portion 33ML, the distance LPQ and the distance LPR are any Is also immutable. That is, in the conveyance main body 33M, the distance from the point P to the lower interlocking gear 54 is always constant, and the distance from the point P to the upper interlocking gear 74 is also constant.

  Further, the center of rotation of the intermediary gear 82 coincides with the point P which is the center of the pivot shaft 81. For this reason, in the conveyance main body 33M, regardless of the rotation angle of the conveyance main body upper portion 33MU with respect to the conveyance main body lower portion 33ML, a state in which the intermediate gear 82 and the lower interlocking gear 54 are engaged, and the intermediate gear 82 and the upper interlocking gear 74 The meshed state can always be maintained.

  As a result, in the conveyance main body 33M, even when the conveyance main body upper part 33MU is opened and closed with respect to the conveyance main body lower part 33ML, the position where the lower carriage 53 and the upper carriage 73 are aligned in the left and right direction can be maintained, and a transmission type sensor is formed. The relative positions of the light emitting element 78 and the light receiving element 58 can be kept constant.

  Incidentally, when the lower interlocking gear 54 and the intermediary gear 82 are considered to be fixed in the transport main body 33M, when transitioning from the closed side state shown in FIG. 7A to the open state shown in FIG. 7B. The upper interlocking gear 74 meshing with the intermediary gear 82 is rotated. Therefore, even if the mutual positions of the light emitting element 78 and the light receiving element 58 are aligned in the closed state, the upper carriage 73 rotates because the upper interlocking gear 74 and the upper screw shaft 72 rotate when transitioning to the open state. It will move slightly in the left-right direction, and this mutual position will shift slightly.

  However, in the transport main body 33M, when the open state is again changed to the closed state, the upper interlocking gear 74 meshing with the intermediation gear 82 is rotated by the same amount of rotation in the opposite direction. As a result, in the transport main body 33M, the relative positions of the light emitting element 78 and the light receiving element 58 are set in order to rotate the upper interlocking gear 74 and the upper screw shaft 72 in the opposite direction to that in opening to return the upper carriage 73 to the original position. It can be aligned again.

[1-3. Effect etc]
In the above configuration, in the conveyance main body 33M of the image forming apparatus 1 according to the first embodiment, the lower carriage 53 on which the light receiving element 58 is mounted is moved in the left and right direction by the rotation of the lower screw shaft 52. The upper carriage 73 mounted thereon is moved in the left-right direction by the rotation of the upper screw shaft 72. Further, in the conveyance main body 33M, the lower interlocking gear 54 and the upper interlocking gear 74 attached to the lower screw shaft 52 and the upper screw shaft 72 respectively mesh with the intermediary gear 82 to configure the interlocking unit 80, interlocking their rotations I let it go.

  Thus, in the transport main body 33M, the light emitting element 78 and the light receiving element 58 positioned opposite to each other with respect to the sheet P can be moved by the same distance in the left direction or the right direction. While maintaining the position, the detection position can be freely displaced to the left and right.

  Further, in the conveyance main body portion 33M, the conveyance main body lower portion 33ML and the conveyance main body upper portion 33MU are connected via the left rotation shaft 81L and the right rotation shaft 81R. Therefore, during the operation of transporting the sheet P, the transport body portion 33M causes the transport rollers of the transport roller pairs 43A, 43B, and 43C to move up and down, with the lower surface of the transport upper portion 33MU and the upper surface of the transport lower portion 33ML facing each other. Adjacent one another allows the sheet P to be properly transported along the transport path 30Y (FIG. 3A). On the other hand, during the operation of transporting the sheet P, the transport body 33M separates the transport path 30Y by removing the transport body upper portion 33MU and the transport body lower portion 33ML, and removes the lower guide plate 59 and the upper guide plate. The efficiency of maintenance work such as cleaning of 79 can be improved (FIG. 3 (B)).

  Further, in the transfer main body portion 33M, the rotation center of the transfer main body upper portion 33MU with respect to the transfer main body lower portion 33ML and the rotation center of the intermediation gear 82 are aligned (FIG. 7). Thereby, in the conveyance main body portion 33M, even if the conveyance main body upper portion 33MU is rotated with respect to the conveyance main body lower portion 33ML, meshing of the gears in the interlocking portion 80, that is, meshing of the lower interlocking gear 54 and the intermediary gear 82 and the intermediary gear Both the engagement of the gear 82 and the upper interlocking gear 74 can be maintained. For this reason, the transport body portion 33M can maintain the mutual position in the lateral direction between the upper carriage 73 and the lower carriage 53 regardless of the opening and closing of the transport body upper portion 33MU with respect to the transport body lower portion 33ML. The detection accuracy of the transmission type sensor by the element 58 can be maintained.

  By the way, in the conveyance main body portion 33M, even if the rotation center of the conveyance main body upper portion 33MU with respect to the conveyance main body lower portion 33ML, that is, the center of the rotation shaft 81 coincides with the rotation center of the lower screw shaft 52, Maintain gear meshing. However, in this case, with the lower interlocking gear 54 fixed to the lower screw shaft 52, the load of the upper transport body upper part 33MU is applied to the lower screw shaft 52, so that the lower screw shaft 52 and the lower interlocking gear 54 are difficult to rotate. turn into.

  At this point, the conveyance main body 33M causes the rotation center of the conveyance main body upper portion 33MU with respect to the conveyance main body lower portion 33ML to coincide with the rotation center of the intermediate gear 82, and rotates the intermediate gear 82 81 L) can be freely rotated. Therefore, even if the load on the upper part 33MU of the transfer body is applied to the rotating shaft 81, the transfer body 33M can easily rotate the intermediation gear 82 and smoothly interlock the upper carriage 73 and the lower carriage 53. .

  Further, the transport main body 33M has the knob interlocking gear 55 attached to the lower screw shaft 52, and the knob interlocking gear 55 and the operation knob 61 are engaged (FIG. 5A). Therefore, the conveyance main body 33M can rotate the gears of the interlocking unit 80, the lower screw shaft 52, and the upper screw shaft 72 only by rotating the operation knob 61 by the operation of the user. The upper carriage 73 can be easily interlocked and moved.

  According to the above configuration, the transport main body 33M is screwed with the lower interlocking gear 54 attached to the lower screw shaft 52 screwed with the lower carriage 53 having the light receiving element 58 and the upper carriage 73 having the light receiving element 58 The upper interlocking gear 74 attached to the upper screw shaft 72 and the intermediate gear 82 are engaged with each other to constitute an interlocking portion 80. Further, the conveyance main body 33M causes the rotation center of the conveyance main body upper portion 33MU with respect to the conveyance main body lower portion 33ML to coincide with the rotation center of the intermediation gear 82. Thereby, in the conveyance main body 33M, even if the conveyance main body upper part 33MU is rotated with respect to the conveyance main body lower part 33ML, meshing of each gear in the interlocking part 80 can be maintained, and a transmission type sensor by the light emitting element 78 and the light receiving element 58 Can maintain the detection accuracy of

[2. Second embodiment]
The image forming apparatus 101 (FIG. 1) according to the second embodiment is different from the image forming apparatus 1 according to the first embodiment in that a conveyance cutting unit 103 is used instead of the conveyance cutting unit 3. The other points are similarly configured. The conveying and cutting unit 103 is different from the conveying and cutting unit 3 in that it has a sheet detection sensor unit 126 that replaces the sheet detection sensor unit 26, but is configured in the same manner in the other points.

[2-1. Configuration of paper detection sensor unit]
As shown in FIG. 8 and the left side view in FIG. 9, the sheet detection sensor unit 126 is roughly divided into a main body lower portion 130 which mainly occupies the lower portion of the conveyance path 22Y (FIG. 1) And an upper main body 140 occupying the upper portion of the transport path 22Y.

  As a whole, the lower main body 130 is formed in a relatively short rectangular shape in the vertical direction, and there is a space to accommodate the lower half of the paper cutting portion 28 (FIG. 1) near the center in the front-rear direction in the upper portion It is formed. A lower sensor unit 150 is disposed at a location on the front side of the sheet cutting unit 28 in the lower main body 130.

  In the vicinity of the rear end of both the left and right side surfaces of the lower main body 130, support plates 131 are provided so as to stand upward. The support plate 131 has its upper end reaching above the transport path 22Y. In the vicinity of the upper end of the support plate 131, an axial hole 131H penetrating in the left-right direction is bored.

  The upper main body 140 is formed in a rectangular shape relatively short in the vertical direction as a whole, and there is a space to accommodate the upper half of the sheet cutting portion 28 (FIG. 1) near the center in the front-rear direction in the lower portion. It is formed. Further, the upper front portion of the upper main body 140 is formed with an inclined surface which is cut off obliquely. Further, an upper sensor unit 170 is disposed at a position on the front side of the sheet cutting unit 28 in the upper main body 140.

  A pivot shaft 141 is provided in the vicinity of the rear end of both the left and right side surfaces of the upper main body 140. The pivot shaft 141 is formed in a short cylindrical shape with the central axis directed in the left and right direction, and is provided protruding outward from the left and right sides of the upper portion 140 of the main body. The pivot shaft 141 is inserted into an axial hole 131 H formed in the support plate 131 of the lower main body 130. Thus, the upper main body 140 can be pivoted about the pivot shaft 141 with respect to the lower main body 130, as in the case of the upper transport main body 33MU (FIG. 3) in the first embodiment.

[2-2. Configuration of lower sensor section]
The lower sensor unit 150 (FIG. 8) is configured to be supported from the vicinity of both left and right ends by the left side plate 132L and the right side plate 132R fixed to the lower main body 130. The left side plate 132L and the right side plate 132R are formed in a thin plate shape in the left-right direction, and respectively support the lower first regulation shaft 151, the lower screw shaft 152, and the lower second regulation shaft 153 in the vicinity of the left and right ends. .

  As shown in FIG. 10 (B), the lower first restricting shaft 151 and the lower second restricting shaft 153 are formed in an elongated cylindrical shape with the central axis along the left and right direction, and the left side plate 132L and the right side plate 132R Each is rotatably supported by (FIG. 8). Incidentally, the lower first restricting shaft 151 is longer in the left-right direction than the lower second restricting shaft 153.

  The lower screw shaft 152 is formed in an elongated cylindrical shape having a central axis along the left and right direction, similarly to the lower screw shaft 52 (FIG. 3, FIG. 6, etc.) according to the first embodiment. A spiral groove (threaded groove) is incised. The lower screw shaft 152 is rotatably supported by the left side plate 132L and the right side plate 132R (FIG. 8).

  A lower interlocking gear 154 is attached near the left end of the lower screw shaft 152. The lower interlocking gear 154 is formed in the shape of a thin disc in the left-right direction, as with the lower interlocking gear 54 according to the first embodiment, and a plurality of teeth are formed on the circumferential side surface thereof. ) Is configured. The lower interlocking gear 154 is fixed to the lower screw shaft 152 by inserting the lower screw shaft 152 into a hole formed at the center.

  The lower sensor unit 150 is provided with a lower carriage 155 corresponding to the lower carriage 53 in the first embodiment. The lower carriage 155 is formed in a relatively small rectangular parallelepiped shape, and through holes 155H1, 155H2 and 155H3 penetrating in the left-right direction are respectively drilled. Among them, the through hole 155H2 has a spiral groove (i.e., a screw groove) incised on the inner circumferential side surface as the through hole 53H in the first embodiment, and is screwed with the screw groove of the lower screw shaft 152 . On the other hand, in the through holes 155H1 and 155H3, no groove is formed on the inner peripheral side surface, and the through holes 155H1 and 155H3 slide smoothly with respect to the lower first restricting shaft 151 and the lower second restricting shaft 153, respectively.

  In the lower carriage 155, the lower first restriction shaft 151, the lower screw shaft 152 and the lower second restriction shaft 153 are respectively inserted through the through holes 155H1, 155H2 and 155H3 when the lower sensor unit 150 is assembled. At this time, the lower carriage 155 is moved in the vertical and longitudinal directions with respect to the lower main body 130 by inserting the lower first restricting shaft 151 and the lower second restricting shaft 153 into the through holes 155H1 and 155H3, respectively. The rotation of each is regulated. In other words, the lower first restriction shaft 151 and the lower second restriction shaft 153 are the reference of the position of the lower carriage 155 in the front-rear direction and the vertical direction.

  When the lower screw shaft 152 is rotated in any direction, the lower carriage 155 engages the screw groove with the through hole 155H2 to thereby lower the lower screw shaft 152 and the lower first restriction. It moves leftward or rightward along the shaft 151 and the lower second regulation shaft 153.

  Further, in the lower carriage 155, similarly to the lower carriage 53, a reflection sensor 157 and a light receiving element 158, which are configured similarly to the reflection sensor 57 and the light receiving element 58, respectively, are incorporated at the back and front positions on the upper side. ing. A lower guide plate 159 (FIG. 9) configured similarly to the lower guide plate 59 is disposed between the upper surface of the lower carriage 155 and the transport path 22Y.

  Further, lock levers 160 (FIG. 10) are provided in the vicinity of the left and right ends of the lower first restriction shaft 151, respectively. The lock lever 160 is generally formed in a thin plate shape which is thin in the left-right direction and elongated in the vertical direction. In the vicinity of the lower end of the lock lever 160, a mounting hole 161 which is a round hole penetrating in the left-right direction is bored. The lock lever 160 is fixed to the lower first restricting shaft 151 by inserting the lower first restricting shaft 151 into the mounting hole 161, and is integral with the lower first restricting shaft 151 with its central axis as a rotation center. Can be turned.

  At the approximate center of the upper and lower sides of the rear side of the lock lever 160, a rectangular rear notch 162 is formed. The front end portion of a spring 168 formed of a coil spring is attached to the rear end portion 162. The spring 168 is attached to the lower main body 130 at its rear end portion, and is adapted to expand and contract in the front-rear direction.

  Therefore, when a force directed rearward toward the upper end is applied to the lock lever 160, the lock lever 160 pivots counterclockwise as viewed from the left side, that is, in the direction of the arrow S2, while compressing the spring 168. When the applied force is released, the lock lever 160 is turned clockwise as viewed from the left side, that is, in the direction of the arrow S1 due to the action of the restoring force of the spring 168.

  An oblique side 163 is formed near the upper end of the lock lever 160 by obliquely cutting off the front upper end. Under the oblique side 163, a front notch 164 which is a substantially rectangular cutout toward the rear is formed. The upper side of the front notch portion 164 is referred to as an engagement side 165. The engagement side 165 is substantially orthogonal to the front side and the rear side of the lock lever 160, and substantially along the front-rear direction.

[2-3. Configuration of upper sensor section]
The upper sensor unit 170 is supported from the vicinity of both left and right ends by the left side plate 142L and the right side plate 142R fixed to the upper main body 140, and has a configuration similar to the lower sensor unit 150. That is, in the upper sensor unit 170, an upper first regulation shaft 171 and an upper screw shaft 172 which are configured substantially the same as the lower first regulation shaft 151, the lower screw shaft 152 and the lower second regulation shaft 153 of the lower sensor unit 150, respectively. The upper second regulation shaft 173 is provided.

  As shown in FIG. 10A, the upper first regulation shaft 171, the upper screw shaft 172 and the upper second regulation shaft 173 are rotatably supported by the left side plate 142L and the right side plate 142R (FIG. 8), respectively. . In the vicinity of the left end of the upper screw shaft 172, an upper interlocking gear 174 configured similarly to the lower interlocking gear 154 is attached.

  The upper sensor portion 170 is provided with an upper carriage 175 corresponding to the upper carriage 73 in the first embodiment. The upper carriage 175 is formed in a relatively small rectangular parallelepiped shape similar to the lower carriage 155, and through holes 175H1, 175H2 and 175H3 similar to the through holes 155H1, 155H2 and 155H3 are bored.

  The upper carriage 175 has the upper first regulation shaft 171, the upper screw shaft 172, and the upper second regulation shaft 173 inserted through the through holes 175H1, 175H2 and 175H3 when the upper sensor unit 170 is assembled. At this time, the upper carriage 175 is moved in the vertical and longitudinal directions with respect to the main body upper portion 140 by inserting the upper first restricting shaft 171 and the upper second restricting shaft 173 into the through holes 175H1 and 175H3. The rotation of each is regulated. In other words, the upper first restricting shaft 171 and the upper second restricting shaft 173 are the reference of the position of the upper carriage 175 in the front-rear direction and the vertical direction.

  When the upper screw shaft 172 is rotated in any direction, the upper carriage 175 has the screw groove mutually screwed with the through hole 175H2, whereby the upper screw shaft 172 and the upper first restriction are formed. It moves leftward or rightward along the shaft 171 and the upper second regulation shaft 173.

  Furthermore, in the upper carriage 175, similarly to the upper carriage 73 in the first embodiment, a light emitting element 178 configured similarly to the light emitting element 78 is incorporated at a rear side and a front side at the upper side. . Further, an upper guide plate 179 (FIG. 9) configured similarly to the upper guide plate 79 is disposed between the lower surface of the upper carriage 175 and the transport path 22Y.

[2-4. Opening and closing the paper detection sensor]
By the way, on the left side of the sheet detection sensor unit 126, as shown in FIGS. 9A and 9B, an intermediary gear 182 having the rotation shaft 141 of the upper portion 140 of the main body as a rotation center is provided. Similar to the intermediary gear 82 in the first embodiment, the intermediary gear 182 is configured as a gear and can freely rotate with respect to the pivot shaft 141.

  Further, on the left side of the sheet detection sensor unit 126, a lower intermediary gear group 183 consisting of a plurality of gears for transmitting a driving force between the lower interlocking gear 154 and the intermediary gear 182, an upper interlocking gear 174 and an intermediary gear 82. An upper intermediate gear group 184 is provided which is composed of a plurality of gears for transmitting the driving force between them. Each gear of the lower intermediary gear group 183 is supported by a gear support member (not shown) so as to be freely rotatable while maintaining its position relative to the lower main body 130. Similarly, each gear of the upper intermediary gear group 184 is supported by a gear support member (not shown) so as to be freely rotatable while maintaining its position relative to the upper main body 140. For convenience of description, the lower interlocking gear 154, the upper interlocking gear 74, the intermediary gear 182, the lower intermediary gear group 183, and the upper intermediary gear group 184 will be collectively referred to as an interlocking unit 180 below.

  With this configuration, in the sheet detection sensor unit 126, as in the first embodiment, the lower screw shaft 152 and the lower interlocking gear 154, and the upper screw shaft 172 and the upper interlocking gear 174 can be interlocked and rotated. . Thus, in the sheet detection sensor unit 126, it is possible to interlock the lower carriage 155 and the upper carriage 175, that is, to move the same distance in the same direction.

  Further, in the sheet detection sensor unit 126, the rotation center of the upper main body 140 with respect to the lower main body 130 and the rotation center of the intermediate gear 182 are made to coincide with each other. As a result, in the sheet detection sensor unit 126, either the state (FIG. 9A) or the state closed (FIG. 9B) in which the upper portion 140 of the main body lower portion 130 is opened, or any state in between. Also, the gears of the interlocking portion 180 can be maintained meshed with each other, and the relative positions of the lower carriage 155 and the upper carriage 175 in the left-right direction can be maintained.

  In the paper detection sensor unit 126 (FIGS. 8 and 9), a force (not shown) is biased in a direction away from the lower main body 130 by a spring (not shown). In the sheet detection sensor unit 126, as shown in FIG. 11 corresponding to FIGS. 10A and 10B, the engagement side 165 of the lock lever 160 is closed in the closed state (FIGS. 8 and 9A). The upper first control shaft 171 is engaged with the upper main body 140.

  Here, in the sheet detection sensor unit 126, when the upper main body 140 is transitioned from the closed state (FIG. 9A) to the open state (FIG. 9B), the user moves the lock lever 160 in the backward direction by the user. Once added, the lock lever 160 pivots while compressing the spring 168. When the engagement of the locking side 160 of the lock lever 160 with the upper first restricting shaft 171 is released in the paper detection sensor unit 126, the rotation of the upper main body 140 with respect to the lower main body 130 becomes possible.

  On the other hand, in the sheet detection sensor unit 126, when the upper main body 140 is transitioned from the open state (FIG. 9B) to the closed state (FIG. 9A), the upper main body 140 is rotated so as to approach the lower main body 130. The engagement side 165 of the lock lever 160 can be engaged with the upper first regulation shaft 171 simply by moving it.

  Specifically, as shown schematically in FIG. 12 (A) and FIG. 12 (B) in which a part of the sheet detection sensor unit 126 is enlarged, the upper part 140 (FIG. 9 etc.) centering on the pivot shaft 141. The upper first regulation shaft 171 moves while drawing the trajectory LC by the rotation of. Incidentally, the locus LC is part of an arc centered on the pivot shaft 141.

  When the upper main body 140 is in the open state, the upper first regulation shaft 171 is at, for example, the shaft position 171A in the figure. When a worker or the like applies a downward force to the main body upper portion 140, the main body upper portion 140 is pivoted in the direction approaching the main body lower portion 130 (FIG. 9 and the like), that is, downward. The upper first restricting shaft 171 eventually reaches the shaft position 171 B and abuts on the oblique side 163 of the lock lever 160.

  Here, when the upper body portion 140 is further rotated downward, the upper first regulation shaft 171 applies a backward force to the lock lever 160 via the oblique side 163, and slides the spring 168 while sliding with the oblique side 163. The lock lever 160 is rotated backward while being compressed. When the upper first restricting shaft 171 reaches the lower end of the oblique side 163, the action of the rearward force on the lock lever 160 via the oblique side 163 is ended. Incidentally, at this time, the lock lever 160 is in the attitude shown by the broken line in the figure.

  In response, the spring 168 releases the applied force and expands, causing the lock lever 160 to pivot forward. Thereby, the upper first regulation shaft 171 enters the front notch portion 164 of the lock lever 160. Incidentally, the lock lever 160 is stopped in a posture shown by a solid line in the figure by bringing a part of the front side into contact with a stopper not shown.

  The upper body portion 140 also ends downward pivoting by abutting on a stopper (not shown). At this time, the upper first restricting shaft 171 reaches a shaft position 171C slightly lower than the engagement side 165 of the lock lever 160. Thereafter, when the downward force from the worker or the like is released, the upper body portion 140 is urged upward and slightly pivoted by the action of a spring (not shown), and the upper first regulation shaft 171 is locked by the lock lever. It arrives at the shaft position 171D made to abut on the engagement side 165 of 160, and stops. Thus, the upper body portion 140 is in the closed state, and the closed state is stably maintained by the engagement of the engagement side 165 of the lock lever 160 with the upper first regulating shaft 171.

[2-5. Effect etc]
In the above-described configuration, the sheet detection sensor unit 126 of the image forming apparatus 101 according to the second embodiment has the main body upper portion 140 in which the upper sensor portion 170 is incorporated with respect to the main body lower portion 130 in which the lower sensor portion 150 is incorporated. It was configured to be rotatable (Fig. 9). Further, the sheet detection sensor unit 126 has the lock lever 160 attached to the lower first restriction shaft 151, and in the closed state, the engagement side 165 of the lock lever 160 is engaged with the upper first restriction shaft 171 (FIG. 11). etc).

  For this reason, when the upper main body 140 is in the closed state, the sheet detection sensor unit 126 always adjusts the distance between the upper first restricting shaft 171 and the lower first restricting shaft 151 to a fixed distance by the lock lever 160. Can. Thus, in the sheet detection sensor unit 126, when the upper body portion 140 is in the closed state, the light emitting element 178 of the upper carriage 175 through which the upper first restriction shaft 171 is inserted and the lower carriage into which the lower first restriction shaft 151 is inserted. The distance between the light receiving element 155 and the light receiving element 155 can always be a fixed distance.

  Further, the paper detection sensor unit 126 is provided with the interlocking unit 180, so that the upper carriage 175 and the lower carriage 155 can be used regardless of the opening and closing of the upper main portion 140 as in the case of the conveyance main body 33M in the first embodiment. It can always be interlocked.

  Accordingly, when the sheet detection sensor unit 126 can align the light emitting element 178 of the upper carriage 175 and the light receiving element 158 of the lower carriage 155 always in mutually corresponding positions in the left-right direction, and the upper main body 140 is closed. In addition, it is possible to keep constant the distance between each other in the vertical direction. As a result, the paper detection sensor unit 126 can open and close the upper main body 140 with respect to the lower main body 130, thereby improving the efficiency of maintenance work, and optimizing the detection accuracy of the transmission type sensor configured by the light emitting element 178 and the light receiving element 158. It can be maintained in

  In particular, the sheet detection sensor unit 126 has a configuration in which the sheet cutting unit 28 is sandwiched between the upper carriage 175 and the lower carriage 155 and the pivot shaft 141 (FIG. 8), and in particular, the conveyance according to the first embodiment. The distance between the transmission sensor and the pivot shaft 81 or 141 is larger than that of the main body 33M. Therefore, in the sheet detection sensor unit 126, even if the main body upper portion 140 is slightly rotated with respect to the main body lower portion 130, the distance between the light receiving element 158 and the light emitting element 178 may greatly change.

  Therefore, the sheet detection sensor unit 126 is a reference of the position of each of the upper carriage 175 and the lower carriage 155 in the closed state, and the distance between the upper first regulation shaft 171 and the lower first regulation shaft 151 located most recently is , And kept constant by the lock lever 160. Thus, the sheet detection sensor unit 126 can maintain the detection accuracy of the transmission type sensor without being affected by the distance from the pivot shaft 141 to the light receiving element 158 and the light emitting element 178.

  By the way, when the sheet detection sensor unit 126 causes the upper first regulation shaft 171 to slide on the oblique side 163 of the lock lever 160 temporarily when transitioning the upper main body 140 from the open state to the closed state, the engagement side 165 continues. In the case where the upper first regulation shaft 171 is brought into contact with the second side, the upper first regulation shaft 171 may be caught in the vicinity of the front end of the engagement side 165. At this time, although the upper part 140 of the main body 140 appears to be properly closed in the sheet detection sensor part 126, the engagement between the upper first regulation shaft 171 and the engagement side 165 of the lock lever 160 can be obtained with only slight vibration or the like. If the sheet P is released, the upper portion 140 of the main body may be released, and the sheet P may not be properly detected.

  Based on this point, the sheet detection sensor unit 126 slides the upper first regulation shaft 171 to the oblique side 163 of the lock lever 160 when the upper body portion 140 is transitioned from the open state to the closed state, and then the engagement side is engaged. Once pulled away from 165, it is again brought into contact with the engagement side 165 and engaged with the engagement side 165 (FIG. 12). Thus, the sheet detection sensor unit 126 can properly return the lock lever 160 to the attitude at the time of engagement (shown by a solid line in the figure).

  For this reason, in the sheet detection sensor unit 126, when the upper portion 140 of the main body is changed from the open state to the closed state, the user applies a downward force to the upper portion 140 of the main body. You just have to release the power. As a result, in the sheet detection sensor unit 126, the upper first regulation shaft 171 can be properly engaged near the center of the engagement side 165 of the lock lever 160, and the engagement is not released by a slight vibration or the like. The detection accuracy of the sheet P by the transmission sensor can be reliably maintained.

  Also in other points, the sheet detection sensor unit 126 can exhibit the same function and effect as the conveyance main body 33M according to the first embodiment.

  According to the above configuration, the sheet detection sensor unit 126 attaches the lock lever 160 to the lower first restriction shaft 151 through which the lower carriage 155 is inserted, and the upper carriage 175 is inserted when the upper portion 140 is closed. The engagement side 165 of the lock lever 160 is engaged with the first restricting shaft 171. Accordingly, when the upper main body 140 is in the closed state, the sheet detection sensor unit 126 adjusts the distance between the upper first regulation shaft 171 and the lower first regulation shaft 151 to a constant distance. The detection accuracy as a transmission type sensor can be maintained by keeping the distance between the lower carriage 155 and the light receiving element 158 of the lower carriage 155 constant.

[3. Other embodiments]
In the first embodiment described above, the case has been described in which the rotation center of the upper transport body upper portion 33MU with respect to the lower transport body lower portion 33ML coincides with the rotation center of the intermediate gear 82 (FIG. 7). However, the present invention is not limited to this. For example, the rotation center of the upper transport main body 33MU with respect to the lower transport main body 33ML may be matched with the rotation centers of the lower interlocking gear 54 and the upper interlocking gear 74. The point is that the rotational center of the upper transport body upper portion 33MU with respect to the lower transport body lower portion 33ML matches the rotational center of any of the gears constituting the interlocking portion 80, so that each gear can be rotated regardless of the rotation of the upper transport body upper portion 33MU. It is good if the meshing of the two can always be maintained. The same applies to the second embodiment.

  In the first embodiment described above, the case where the interlocking portion 80 is configured by a combination of three gears (gears) has been described (FIG. 7). However, the present invention is not limited to this. For example, the interlocking portion may be configured by a belt, a link mechanism, or a combination of these with a gear. The point is that the rotation of the lower screw shaft 52 and the rotation of the upper screw shaft 72 can be interlocked, and the interlock can be always performed also when the upper transport body upper portion 33MU rotates with respect to the lower transport lower portion 33ML. The same applies to the second embodiment.

  Further, in the first embodiment described above, by transmitting the rotation of the operation knob 61 to the lower screw shaft 52 and the upper screw shaft 72, the lower carriage 53 and the upper carriage 73 are rotated in response to the rotation of the operation knob 61. I mentioned the case of moving it. However, the present invention is not limited to this. For example, the operation knob 61 and the knob interlocking gear 55 may be omitted, and the user may directly move the upper carriage 73. In this case, since the interlocking unit 80 transmits the driving force, the lower carriage 53 can be moved to follow the upper carriage 73.

  Furthermore, in the first embodiment described above, the case where the vertical and horizontal positions of the lower carriage 53 are defined by the lower screw shaft 52 and the guide rail 56R has been described. However, the present invention is not limited to this. For example, as in the lower carriage 155 in the second embodiment, the lower carriage is provided by the lower first restriction shaft 151 and the lower second restriction shaft 153 provided separately from the lower screw shaft 152. The positions of the vertical direction 53 and the horizontal direction may be defined.

  Furthermore, in the first embodiment described above, the case where the light emitting element 78 is provided on the upper carriage 73 and the light receiving element 58 is provided on the lower carriage 53 has been described. However, the present invention is not limited to this. For example, the light receiving element 58 may be provided on the upper carriage 73 and the light emitting element 78 may be provided on the lower carriage 53. Alternatively, not only the light emitting element 78 and the light receiving element 58 constituting the transmission type sensor, light or electromagnetic wave is transmitted from one side of the sheet P, and various characteristics of the sheet P are received by receiving it on the opposite side. The various elements for detecting may be distributed to the upper carriage 73 side and the lower carriage 53 side. The same applies to the second embodiment.

  Furthermore, in the first embodiment described above, the radius and shape and number of teeth of the lower interlocking gear 54 and the upper interlocking gear 74 are made equal, and the pitch and diameter of the screw groove in the lower screw shaft 52 and the upper screw shaft 72 are set. I mentioned about the case to be equal. As a result, in the first embodiment, the rotational speeds of the lower screw shaft 52 and the upper screw shaft 72 at the time of interlocking can be matched, and the lower carriage 53 and the upper carriage 73 can be moved by the same distance in the same direction. However, the present invention is not limited to this, for example, the radius of the lower interlocking gear 54 and the upper interlocking gear 74, the shape and number of teeth are different, or the pitch and diameter of the screw groove in the lower screw shaft 52 and the upper screw shaft 72 are different. You may In this case, it is sufficient that the lower carriage 53 and the upper carriage 73 can be moved by the same distance in the same direction at the time of interlocking by appropriately setting the ratio of the respective values.

  Further, in the above-described first embodiment, in addition to the light emitting element 78 and the light receiving element 58 constituting the transmission type sensor, the conveying roller pair 43 A etc. I mentioned the case of incorporating. However, the present invention is not limited to this. For example, as in the case of the sheet detection sensor unit 126 according to the second embodiment, the conveyance roller pair may not be incorporated.

  Furthermore, in the second embodiment described above, the lock lever 160 is attached to the lower first restriction shaft 151 of the lower sensor unit 150, and the lock lever 160 is engaged with the upper first restriction shaft 171 of the upper sensor unit 170. I mentioned the case. However, the present invention is not limited thereto. For example, the lock lever 160 may be attached to the lower second regulation shaft 153 of the lower sensor unit 150, or the lock lever 160 may be attached to the upper second regulation shaft 173 or the upper sensor unit 170. The screw shaft 172 may be engaged. Furthermore, the lock lever 160 may be attached to the upper first regulation shaft 171 or the like on the upper sensor unit 170 side and engaged with the lower first regulation shaft 151 or the like on the lower sensor unit 150 side.

  Furthermore, in the second embodiment described above, the case where the lock lever 160 is attached to the left and right sides of the lower first restriction shaft 151 has been described. However, the present invention is not limited to this. For example, the lock lever 160 may be attached to only one of the left and right of the lower first restriction shaft 151.

  Furthermore, in the second embodiment described above, the case has been described in which the upper body portion 140 is urged in a direction of pulling away from the lower body portion 130 by a spring (not shown). However, the present invention is not limited to this, and for example, this spring may be omitted. The same applies to the first embodiment.

  Furthermore, in the first embodiment described above, the case where the sheet P is a so-called label sheet has been described (FIG. 2). However, the present invention is not limited to this, and the sheet P may be a sheet having various configurations. In this case, it is sufficient that the transmission type sensor constituted by the light emitting element 78 and the light receiving element 58 can detect the position on the sheet P where the image should be formed. The sheet P is not limited to a long sheet, but may be a cut sheet of relatively short length such as A4 size. The same applies to the second embodiment.

  Furthermore, the present invention is not limited to the above-described embodiments and other embodiments. That is, the present invention can be applied to an embodiment in which any or all of the above-described embodiments and any of the other embodiments described above are arbitrarily combined or an embodiment in which a part is extracted. It is.

  Further, in the first embodiment described above, the lower transport main body 33ML as the first main body, the upper transport main body 33MU as the second main body, and the left pivot shaft 81L and the right turn as the main body pivot. A dynamic shaft 81R, a lower screw shaft 52 as a first screw shaft, an upper screw shaft 72 as a second screw shaft, a lower carriage 53 as a first carriage, an upper carriage 73 as a second carriage, and transmission The case where the transport main body 33M as the medium detection device is configured by the light emitting element 78 as the element, the light receiving element 58 as the receiving element, and the interlocking unit 80 as the interlocking unit has been described. However, the present invention is not limited to this, and other various configurations of the first main body portion, the second main body portion, the main body rotation portion, the first screw shaft, the second screw shaft, and the first carriage. The medium detection device may be configured by the second carriage, the transmission element, the reception element, and the interlock unit.

  The present invention can be used, for example, in an image forming apparatus which detects the position of a sheet and forms an image in accordance with the position.

1, 101 ... image forming apparatus, 2 ... main body, 3, 103 ... conveyance cutting unit, 5 ... control unit, 22 Y ... conveyance path, 26, 126 ... sheet detection sensor unit, 28 ... sheet Cutting part 30 ... housing 30Y ... conveyance path 33 ... central conveyance part 33F ... upper part before conveyance, 33M ... conveyance main part, 33ML ... lower part of conveyance main body, 33MU ... upper part of conveyance main body, 34: secondary transfer unit, 35: fixing unit, 43A, 43B, 43C: transport roller pair, 44: detection sensor group, 51L: lower left plate, 51R: lower right plate, 52, 152 ... Lower screw shaft, 53, 155 ... Lower carriage, 53 H ... Through hole, 54, 154 ... Lower interlocking gear, 55 ... Knob interlocking gear, 57, 157 ... Reflection sensor, 58, 158 ... Light receiving element , 61 ... Operation knob, 66 ... Operation lever 67: Lock claw 71L: Upper left side plate 71R Upper right side plate 72, 172 Upper screw shaft 73, 175 Upper carriage 73H Through hole 74, 174 Upper interlock Gears 78, 178 ... light emitting elements, 80, 180 ... interlocking parts, 81 ... rotation axis, 81 L ... left rotation axis, 81 R ... right rotation axis, 82, 182 ... intermediation gear 130 ...... Lower part of body, 140: Upper part of body, 141: Rotating shaft, 150: Lower sensor part, 151: Lower first regulation shaft, 153: Lower second regulation shaft, 160: Lock lever, 163 ...... Diagonal side, 164 ...... front notch portion, 165 ...... engaging side, 168 ...... spring, 170 上 upper sensor portion, 171 上 upper first regulation shaft, 173 上 upper second regulation shaft, 183 ... ... lower intermediary gear group, 184 ... upper rank Gear group, P ...... paper.

Claims (8)

A first main body disposed on one side of a conveyance path for conveying a medium along a predetermined conveyance direction;
A second main body disposed on the other surface side of the transport path;
A body rotation portion configured to rotate the first body portion relative to the second body portion around a body portion rotation axis parallel to the one surface and crossing the transport direction;
A first screw shaft having a central axis extending in a cross direction and having a thread groove formed on a circumferential side, and supported rotatably around the central axis by the first main body;
A second screw shaft having a central axis extending in a cross direction and having a thread groove formed on a circumferential side, and supported rotatably around the central axis by the second main body;
It has a first insertion hole through which the first screw shaft is inserted, and a screw groove screwed with the screw groove of the first screw shaft is formed on the inner peripheral surface of the first insertion hole, and the first screw shaft A first carriage that moves in a cross direction with the rotation of
It has a second insertion hole through which the second screw shaft is inserted, and a thread groove which is screwed with the screw groove of the second screw shaft is formed on the inner peripheral surface of the second insertion hole, the second screw shaft A second carriage that moves in the cross direction with the rotation of
A transmitting element provided on one of the first carriage and the second carriage for transmitting light or an electromagnetic wave to the transport path;
A receiving element provided on the other of the first carriage and the second carriage for receiving the light or the electromagnetic wave from the transport path;
Through the intermediary rotary member which rotates around the mediation center axis which coincides with the main body portion rotation shaft, that it comprises a linkage section that links the rotation of the rotary and the second screw shaft of the first screw shaft A medium detection device characterized by The intermediation rotating body is an intermediation gear in which a tooth is formed on a circumferential side portion,
The interlocking portion rotates the first gear attached to the first screw shaft and the second gear attached to the second screw shaft in conjunction with the intermediate gear. Medium detection device as described. The medium detection device according to claim 2, wherein the intermediate gear freely rotates with respect to the main body rotation shaft. The medium detection device according to claim 2, wherein the first gear and the second gear directly mesh with the intermediation gear. It further comprises an operation knob provided on the first main body or the second main body, rotating about a central axis along the cross direction and interlocking with the first screw shaft or the second screw shaft. The medium detection device according to claim 1, characterized in that: A first guide shaft attached to the first main body in parallel with the first screw shaft and inserted into the first carriage;
A second guide shaft attached to the second main body portion in parallel with the second screw shaft and inserted into the second carriage;
A lock lever for fixing a distance between the first guide shaft and the second guide shaft in a state in which the transmitting element and the receiving element are opposed to each other across the transport path; The medium detection apparatus of claim 1. A main body biasing portion which biases the first main body portion and the second main body portion in a direction in which the first main body portion and the second main body portion are separated from each other when at least the transmitting element and the receiving element face each other across the transport path. Further comprising
7. The medium detection device according to claim 6, wherein the lock lever regulates movement of the first guide shaft and the second guide shaft in directions away from each other. The medium detection device according to any one of claims 1 to 7.
A control unit that determines the position of the medium based on the detection result of the medium detection device;
An image forming unit for transferring and fixing an image formed by a developer according to the position of the medium determined by the control unit;

Images