JP2014227258A - Recording material carrier device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording material carrier device which drives carriage mechanisms by laying a drive transmission belt around individual rotation shafts of opposite carriage mechanisms, prevents twisting of the belt or detachment of the belt from the rotation shafts and allows opening and closing of the carriage mechanisms in a state where the belt is laid around the carriage mechanisms.SOLUTION: A recording material carrier device includes: a first carriage mechanism 31 and a second carriage mechanism 32 which face each other and can carry a recording material P while holding the recording material P between them; drive means 61 for rotation-driving the drive shaft of the second carriage mechanism 32; a drive transmission belt 68 which is extendable and connects the rotation shaft of the first carriage mechanism 31 to the drive shaft of the second carriage mechanism 32 to transmit the driving force of the second carriage mechanism 32 to the rotation shaft of the first carriage mechanism 31; and a rotation shaft 132 which switches the first carriage mechanism 31 between an opened state and a closed state. The length of the circumference of the drive transmission belt 68 is longer in the closed state than in the opened state of the first carriage mechanisms (L1>L2).

Description

  The present invention relates to an electrophotographic image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine including these, and a recording material conveying apparatus used therefor.

  A recording material conveyance device (cooling device) having a cooling member that cools a sheet nipped and conveyed by an opposed belt from the front and back is known (Patent Document 1).

  There is also known a sheet conveying apparatus that opens and closes an opposing belt by a rotation shaft on one end side (Patent Document 2).

  Furthermore, a drive transmission mechanism is also known in which a belt is wound around each of the rotation shafts of the conveying means facing each other and the drive from the drive device is transmitted to each rotation shaft via the belt (Patent Document 3).

  However, in a transport apparatus having a drive transmission mechanism such as that disclosed in Patent Document 3, when the opposite belt is rotated as in Patent Document 2, a problem arises in that the belt transmitting the drive is twisted. If the opening and closing of the belt is repeated in such a state, a load is applied to the belt for transmitting the drive, the belt is damaged, and the driving accuracy is adversely affected.

  Therefore, the present invention provides a recording material conveying apparatus that drives a conveying mechanism by driving a driving transmission belt around each rotating shaft of an opposing conveying mechanism to prevent the belt from being twisted or detached from the rotating shaft. An object of the present invention is to enable the transport mechanism to be opened and closed in a state where it is hung on the transport mechanism.

  In order to solve this problem, in the present invention, a first transport mechanism and a second transport mechanism that are opposed to each other and capable of sandwiching and transporting a recording material, and a drive unit that rotationally drives a drive shaft of the second transport mechanism And connecting the rotational shaft of the first transport mechanism and the drive shaft of the second transport mechanism to transmit the drive of the second transport mechanism to the rotational shaft of the first transport mechanism. A drive transmission belt; and a pivot shaft for opening and closing the first conveyance mechanism in an open state and a closed state, and a circumferential length of the drive transmission belt is an open state of the first conveyance mechanism. A recording material transport device is proposed in which the closed state is longer than the closed state.

  The belt is prevented from being twisted, and high driving accuracy can be maintained. In addition, the first transport mechanism can be opened and closed while the belt is wound around each transport mechanism. In the closed state of the first transport mechanism, the drive from the driving means can be transmitted to the rotation shaft of the first transport mechanism via the drive shaft of the second transport mechanism, while the belt is driven in the open state. It is possible to prevent detachment from the shaft and the rotating shaft.

1 is a schematic configuration diagram of a color image forming apparatus according to an embodiment. It is a schematic block diagram of the cooling device which concerns on embodiment. It is a schematic block diagram of the back side of a cooling device. It is a schematic block diagram of the cooling device which concerns on other embodiment. It is a schematic block diagram of the recording material conveying apparatus which concerns on other embodiment. FIG. 6 is a schematic side view showing a driving roller and a driven roller in a recording material conveying apparatus that does not include a belt. FIG. 5 is a schematic side view showing an opening / closing mechanism for belt conveying means in the recording material conveying apparatus. It is a schematic rear view of a 1st conveyance mechanism and a 2nd conveyance mechanism. It is explanatory drawing about the expansion | extension state of a belt.

  FIG. 1 is a schematic configuration diagram of a color image forming apparatus according to an embodiment. The image forming apparatus shown in FIG. 1 includes a tandem type image forming unit in which four process units 1Y, 1C, 1M, and 1Bk as image forming units are arranged side by side. Each of the process units 1Y, 1C, 1M, and 1Bk is configured to be detachable from the image forming apparatus main body 200, and yellow (Y), cyan (C), magenta (M), and magenta (M) corresponding to the color separation components of the color image. The configuration is the same except that toners of different colors of black (Bk) are accommodated.

  Specifically, each of the process units 1Y, 1C, 1M, and 1Bk includes a drum-shaped photosensitive member 2 as a latent image carrier, a charging roller 3 as a charging unit that charges the surface of the photosensitive member 2, and a photosensitive member. 2 is provided with a developing device 4 as a developing means for forming a toner image on the surface of 2 and a cleaning blade 5 as a cleaning means for cleaning the surface of the photoreceptor 2. In FIG. 1, only the photoconductor 2, the charging roller 3, the developing device 4, and the cleaning blade 5 included in the yellow process unit 1 </ b> Y are denoted by reference numerals. Omitted.

  In FIG. 1, an exposure device 6 as an exposure means for exposing the surface of the photoreceptor 2 is disposed above each process unit 1Y, 1C, 1M, 1Bk. The exposure device 6 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of each photoconductor 2 with laser light based on image data.

  A transfer device 7 is disposed below each process unit 1Y, 1C, 1M, 1Bk. The transfer device 7 has an intermediate transfer belt 10 constituted by an endless belt as a transfer body. The intermediate transfer belt 10 is stretched around a plurality of rollers 21 to 24 as support members, and when one of the rollers 21 to 24 rotates as a driving roller, the intermediate transfer belt 10 is changed to an arrow in the figure. It is configured to run around (rotate) in the direction shown.

  Four primary transfer rollers 11 as primary transfer means are disposed at positions facing the four photoconductors 2. Each primary transfer roller 11 presses the inner peripheral surface of the intermediate transfer belt 10 at each position, and a primary transfer nip is formed at a location where the pressed portion of the intermediate transfer belt 10 and each photoconductor 2 are in contact with each other. ing. Each primary transfer roller 11 is connected to a power source (not shown), and a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to the primary transfer roller 11.

  A secondary transfer roller 12 as a secondary transfer unit is disposed at a position facing one roller 24 that stretches the intermediate transfer belt 10. The secondary transfer roller 12 presses the outer peripheral surface of the intermediate transfer belt 10, and a secondary transfer nip is formed at a location where the secondary transfer roller 12 and the intermediate transfer belt 10 are in contact with each other. Similar to the primary transfer roller 11, the secondary transfer roller 12 is connected to a power source (not shown) so that a predetermined direct current voltage (DC) and / or alternating current voltage (AC) is applied to the secondary transfer roller 12. It has become.

  A plurality of paper feed cassettes 13 that contain sheet-like recording material P such as paper or OHP are disposed below the image forming apparatus main body 200. Each paper feed cassette 13 is provided with a paper feed roller 14 for feeding out the stored recording material P. A paper discharge tray 20 for stocking the recording material P discharged outside the apparatus is provided on the left outer surface of the image forming apparatus main body 200 in the drawing.

  In the image forming apparatus main body 200, a transport path R for transporting the recording material P from the paper feed cassette 13 to the paper discharge tray 20 through the secondary transfer nip is disposed. In the transport path R, a registration roller 15 is disposed upstream of the position of the secondary transfer roller 12 in the recording material transport direction. Further, a fixing device 8, a cooling device 9, and a pair of discharge rollers 16 are sequentially arranged on the downstream side in the recording material conveyance direction from the position of the secondary transfer roller 12. The fixing device 8 includes, for example, a fixing roller 17 as a fixing member having a heater (not shown) therein, and a pressure roller 18 as a pressure member that presses the fixing roller 17. A fixing nip is formed at a position where the fixing roller 17 and the pressure roller 18 are in contact with each other.

  The basic operation of the image forming apparatus will be described below with reference to FIG. When the image forming operation is started, the photoreceptors 2 of the process units 1Y, 1C, 1M, and 1Bk are rotated counterclockwise in the drawing, and the surface of each photoreceptor 2 is made to have a predetermined polarity by the charging roller 3. It is charged like this. Based on image information of a document read by a reading device (not shown), the surface of each photoconductor 2 charged from the exposure device 6 is irradiated with laser light, and an electrostatic latent image is formed on the surface of each photoconductor 2. Is done. At this time, the image information to be exposed on each photoconductor 2 is monochromatic image information obtained by separating a desired full-color image into color information of yellow, cyan, magenta, and black. As the electrostatic latent image formed on the photosensitive member 2 is supplied with toner by each developing device 4, the electrostatic latent image is visualized (visualized) as a toner image.

  One of the rollers that stretches the intermediate transfer belt 10 is driven to rotate, and the intermediate transfer belt 10 runs around in the direction of the arrow in the figure. Also, a primary transfer nip between each primary transfer roller 11 and each photoreceptor 2 is applied to each primary transfer roller 11 by applying a constant voltage or a voltage controlled by a constant current opposite to the charging polarity of the toner. A transfer electric field is formed. Then, the toner images of the respective colors formed on the respective photoconductors 2 are sequentially superimposed and transferred onto the intermediate transfer belt 10 by the transfer electric field formed in the primary transfer nip. Thus, the intermediate transfer belt 10 carries a full-color toner image on its surface. Further, the toner on each photoreceptor 2 that could not be transferred to the intermediate transfer belt 10 is removed by the cleaning blade 5.

  As the paper feed roller 14 rotates, the recording material P is carried out of the paper feed cassette 13. The discharged recording material P is timed by the registration roller 15 and sent to the secondary transfer nip between the secondary transfer roller 12 and the intermediate transfer belt 10. At this time, a transfer voltage having a polarity opposite to the toner charging polarity of the toner image on the intermediate transfer belt 10 is applied to the secondary transfer roller 12, thereby forming a transfer electric field in the secondary transfer nip. Then, the toner images on the intermediate transfer belt 10 are collectively transferred onto the recording material P by the transfer electric field formed in the secondary transfer nip. Thereafter, the recording material P is fed into the fixing device 8, and the recording material P is pressurized and heated by the fixing roller 17 and the pressure roller 18 to fix the toner image on the recording material P. The recording material P is cooled by the cooling device 9 and then discharged to the paper discharge tray 20 by the pair of discharge rollers 16.

  The above description is an image forming operation when a full-color image is formed on a recording material. A single color image is formed using any one of the four process units 1Y, 1C, 1M, and 1Bk, and 2 Two or three process units can be used to form a two or three color image.

  By the way, as shown in FIG. 2, the cooling device as the recording material conveying device includes a cooling member 33 for cooling the sheet-like recording material P conveyed by the belt traveling of the belt conveying means 30. The belt conveying means 30 is arranged on the first conveyance mechanism 31 arranged on one surface (front surface or upper surface) side of the sheet-like recording material P and on the other surface (back surface or lower surface) side of the sheet-like recording material P. The second transport mechanism 32 is provided. Each transport mechanism is provided with a cooling member 33, and a cooling member 33a as a first cooling unit is disposed on one surface (back surface or lower surface) side of the sheet-like recording material P, and serves as a second cooling unit. The cooling member 33b is disposed on the other surface (front surface or upper surface) side of the sheet-shaped recording material P, and the cooling member 33c as the third cooling unit is disposed on the other surface (rear surface or lower surface) side of the sheet-shaped recording material P. Has been.

  The cooling members 33a, 33b, and 33c are arranged so as to be shifted along the traveling direction of the sheet-like recording material. Also, one cooling member 33b is a flat arc-shaped heat absorbing surface 34b whose bottom surface is slightly expanded, and the other cooling members 33a and 33c are flat arc-shaped heat absorbing surfaces whose top surface is slightly expanded. 34a and 34c. In each of the cooling members 33a, 33b, and 33c, a coolant flow path through which the coolant flows is formed.

  As shown in FIG. 3, the cooling device includes a heat receiving part 45 that receives heat from the recording material P as a heat generating part, a heat radiating part 46 that radiates heat from the heat receiving part 45, a heat receiving part 45, and a heat radiating part 46. A coolant circulation circuit 44 having a circulation path 47 through which the coolant circulates. In this circulation path 47, a pump 48 for circulating the coolant and a liquid storage tank 49 for storing the coolant are arranged. Then, the cooling members 33 a, 33 b, and 33 c that are liquid cooling plates are caused to function as the heat receiving unit 45. Further, the heat dissipating part 46 is composed of a radiator or the like. The coolant includes, for example, water as a main component, propylene glycol or ethylene glycol for lowering the freezing temperature, and a rust preventive for preventing rust of metal parts (for example, phosphate-based material: phosphorus Acid potassium salt, inorganic potassium salt and the like).

  As the circulation path 47, a pipe 50 that connects one opening of the cooling member 33c and the liquid storage tank 49, and a pipe 60 that connects the other opening of the cooling member 33a and one opening of the cooling member 33b. A pipe 51 connecting the other opening of the cooling member 33b and one opening of the cooling member 33c, a pipe 52 connecting the other opening of the cooling member 33c and the radiator as the heat radiating section 46, and heat radiation A pipe 53 connecting the radiator as the section 46 and the pump 48 and a pipe 54 connecting the pump 48 and the liquid storage tank 49 are provided. The circulation path 47 having the pipes 50, 60, 51, 52, 53, and 54 forms one flow path, but meanders in the cooling members 33a, 33b, and 33c, so that the cooling liquid is effectively used. The cooling member is cooled.

  The first transport mechanism 31 includes a plurality of (four in the illustrated example) rollers (driven rollers) 55, a belt (conveyance belt) 56 that is wound around the rollers 55, and presses the belt 56 from the outside. One roller (driven roller) 55e for adjusting the tension of the belt 56 is provided. The second transport mechanism 32 includes a plurality (four in the illustrated example) of rollers (driven rollers) 57c, 57d, 58, a drive roller 57a, and a belt (conveyance belt) 59 wound around the rollers 57, 58. With. Each roller is a tension member for the belt.

  Therefore, when the recording material P is conveyed, the recording material P is nipped and conveyed by the belt 56 of the first conveying mechanism 31 and the belt 59 of the second conveying mechanism 32 which are arranged to face each other. Become. That is, when the driving roller 57a is driven, as shown in FIG. 2, the belt 59 travels in the direction of the arrow A, and the second transport mechanism 32 passes through the recording material P sandwiched between the belts 56 and 59. As the belt 59 travels, the belt 56 of the first transport mechanism 31 travels in the arrow B direction. As a result, the recording material P is conveyed from the upstream side to the downstream side along the arrow C direction.

  Here, the driven roller 55e presses the belt 56 from the outside by a spring and adjusts the tension of the belt 56 appropriately. However, if the release is released, the belt 56 bends. Can be removed.

  Next, the operation of the cooling device configured as described above will be described. When the recording material P is nipped and conveyed, as shown in FIG. 2 and the like, the first conveyance mechanism 31 and the second conveyance mechanism 32 are brought close to each other. In the state shown in FIG. 2, if the driving roller 57a of the second transport mechanism 32 is driven to rotate, the belts 56 and 59 run in the direction of the arrow as described above, and the recording material P moves in the direction of the arrow. Run. In this state, the coolant is circulated in the coolant circulation circuit 44. That is, by driving the pump 48, the cooling liquid is caused to flow in the cooling liquid flow paths of the cooling members 33a, 33b, and 33c.

  At this time, the inner surface of the belt 56 of the first transport mechanism 31 slides on the heat absorbing surface 34b of the cooling member 33b, and the inner surface of the belt 59 of the second transport mechanism 32 cools with the heat absorbing surface 34a of the cooling member 33a. The heat absorbing surface 34c of the member 33c is slid. Therefore, the cooling member 33 b absorbs the heat of the recording material P from the front surface (upper surface) side of the recording material P via the belt 56. Further, the cooling members 33 c and 33 a absorb the heat of the recording material P from the back surface (lower surface) side of the recording material P through the belt 59. In this case, the cooling members 33a, 33b, and 33c are kept at a low temperature by transporting the amount of heat absorbed by the cooling members 33a, 33b, and 33c to the outside.

  That is, by driving the pump 48, the coolant circulates in the coolant circulation circuit 44, flows through the coolant flow paths of the cooling members 33 a, 33 b, 33 c, absorbs heat, and becomes a high temperature coolant. By passing through a radiator that functions as a heat radiating section, heat is radiated to the outside air, and the temperature is lowered. Then, the coolant having a low temperature flows again in the coolant flow path, and the cooling members 33 a, 33 b, 33 c function as the heat radiating portion 46. For this reason, the recording material P is cooled from both sides by repeating this cycle.

  In this example, the cooling members 33 are arranged in order of the lower side, the upper side, and the lower side from the upstream side to the downstream side in the conveyance direction C of the recording material P. The cooling members 33a, 33b, and 33c have substantially the same shape, and the number of cooling members on the second transport mechanism 32 side is larger than that on the first transport mechanism 31 side. Accordingly, the total contact area of the cooling members 33a and 33c with the inner peripheral surface of the belt is larger than the contact area of the cooling member 33b with the inner peripheral surface of the belt, and the belt rotation resistance in the first transport mechanism 31 is the second It becomes smaller than the belt rotation resistance in the transport mechanism 32. The drive roller 57a is provided on the second transport mechanism 32 side having a higher belt rotation resistance.

  Here, the top surfaces of the heat absorbing surfaces 34a and 34c arranged on one side across the recording material conveyance path and the top surface of the heat absorption surface 34b arranged on the other side across the recording material conveyance path are in the recording material conveyance direction. It is located so as to be intertwined in the direction intersecting. As a result, the belts are intricately in contact with each other so that the rotation of the belt is stabilized and the difference in rotational speed generated between the conveyance belts is reduced, thereby achieving high-precision conveyance of the recording material by the conveyance belts. Can do.

The recording material conveying apparatus according to the present invention is not limited to the cooling apparatus using the coolant circulation circuit 44, and instead, a heat exhaust promoting shape portion 106 may be provided as shown in FIG. The exhaust heat promoting shape portion 106 is an air-cooled heat sink having a large number of fins. The above-described embodiment can be applied to the relationship between the heat absorbing surfaces 34a, 34b, 34c and the belts 56, 59 at this time.
Thus, by using the air-cooled heat sink structure, the coolant circulation circuit 44 can be omitted, and the apparatus can be made compact and low in cost.

FIG. 5 is a schematic configuration diagram of a recording material transport apparatus according to another embodiment.
The present invention is not limited to the cooling device as described above, and can also be applied to a recording material transport device having no cooling member as shown in FIGS. In this case, as shown in FIG. 5, the driving roller 57a and the driven roller 55a face each other to form a nip. The driven roller 55a rotates with the driving of the driving roller 57a. Further, the recording material conveying apparatus of this example may be in front of the image forming unit or may be behind.
Further, the present invention is not limited to the recording material conveying apparatus having the belt as described above, and is also applied to a recording material conveying apparatus that sandwiches and conveys the recording material by the driving roller 57a and the driven roller 55a as shown in FIG. it can. In this case, the driven roller 55a rotates with the driving roller 57a.

FIG. 7 shows the opening / closing mechanism 130 of the belt conveying means 30 in the recording material conveying apparatus. FIG. 7A shows a state in which the belt conveying unit 30 is closed, and FIG. 7B shows a state in which the belt conveying unit 30 is opened. The right side in the figure corresponds to the back side (R) of the image forming apparatus 200, and the left side in the figure corresponds to the front side (F) of the image forming apparatus. 5 and FIG. 6, the first transport mechanism 31 and the second transport mechanism 32 in FIG. 7 are replaced with the first transport mechanism 31 and the second transport mechanism 32 in FIG. 5 or FIG. Can be applied.
The opening / closing mechanism 130 rotates the support part 131 provided on the back surface of the second transport mechanism 32, the holding part 133 provided on the back surface of the first transport mechanism 31, and the support part 131 and the holding part 133. And a pivot shaft 132 that can be used.

  When the front side (the left side in FIG. 7) of the first transport mechanism 31 is lifted upward (in the O direction), the first transport mechanism 31 rotates about the rotation shaft 132 as shown in FIG. 7B. Move and open. Accordingly, the transport mechanisms 31 and 32 can be separated from each other, so that the user can remove jammed paper or the like between the first transport mechanism 31 and the second transport mechanism 32.

  On the other hand, the conveyance mechanisms 31 and 32 can be made to approach by closing the 1st conveyance mechanism 31 to the C direction of FIG.7 (b). The positions of the transport mechanisms 31 and 32 are determined by a positioning mechanism (not shown) provided in the transport mechanisms 31 and 32.

FIG. 8 is a schematic rear view of the first transport mechanism 31 and the second transport mechanism 32.
As the drive transmission mechanism, a rotation shaft 62 of a drive motor 61 which is a drive means provided on the second transport mechanism 32 side rotates in the clockwise direction in the drawing. The pulley 64a and the pulley 64b are fixed coaxially to form a step pulley. The belt 63 is wound around a rotating shaft 62 and a large-diameter pulley 64a. The pulley 66a and the pulley 66b are fixed to the drive shaft of the drive roller 57a to form a step pulley. The belt 65 is wound around a small-diameter pulley 64b and a small-diameter pulley 66a, and the drive is transmitted to the drive shaft of the drive roller.

  Further, a drive transmission belt 68 (hereinafter referred to as “belt”), which is a feature of the present invention, is connected to a large-diameter pulley 66b as a first pulley and a pulley 69 as a second pulley provided on the first transport mechanism 31 side. 68 ”). Then, the gear 70 provided coaxially with the pulley 69 and the gear 72 provided on the rotation shaft of the driven roller 55a mesh with each other, whereby the driving force from the driving roller 57a is transmitted to the gear 72.

  With this configuration, in the second transport mechanism 32, the drive of the drive motor 61 is transmitted to the drive roller 57a, and the belt 59 (FIGS. 1 to 5) and the drive roller 57a (FIGS. 1 to 5) rotate in a predetermined direction. . In the first transport mechanism 31, the belt 56 (FIGS. 1 to 5) and the driven roller 55a (FIGS. 1 to 5) are transmitted to the rotation shaft of the driven roller 55a via the drive shaft of the drive roller 57a. Is driven to rotate.

The belt 68 is an extensible round belt having a natural length and a substantially circular cross section.
The pulleys 69 and 66b have a circular shape, and include a circumferential groove for attaching the belt 68 and a flange formed on the side surface of the groove. The belt 68 is fitted into the grooves of the pulleys 69 and 66b. The belt 68 is attached to the pulley 69 and the pulley 66b so that the belt 68 is in a tension state in both the opened state and the closed state of the first transport mechanism 31.

  Next, the stretched state of the belt 68 will be described with reference to FIG. 9A is a schematic side view of the natural length before the belt 68 is attached to the pulleys 69 and 66b, and FIG. 9B is a schematic side view showing a state in which the belt 68 is attached to the pulleys 69 and 66b. Further, a solid line in FIG. 9B indicates a state where the first transport mechanism 31 is closed, and a broken line indicates a state where the first transport mechanism 31 is opened. 9B, the right side corresponds to the front side (F) of the image forming apparatus 200, and the left side in FIG. 9B corresponds to the back side (R) of the image forming apparatus.

  Generally, a round belt can be extended within a predetermined range. Here, as shown in FIG. 9 (a), the natural length (natural circumferential length) of the belt 68, which is an endless belt before stretching, is L0, and the circumferential length of the belt 68 in the state shown by the solid line in FIG. 9 (b). Is L1, and the circumferential length of the belt 68 in the state indicated by the broken line in FIG. 9B is L2. The recommended extension range of the belt 68 is LA to LB (0 <LA <LB). At this time, the belt 68 is stretched around the pulleys 69 and 66b so that L0 <LA ≦ L2 <L1 ≦ LB. As can be seen from the above formula, the circumferential lengths L1 and L2 of the belt 68 in the closed state (solid line) and the open state (broken line) of the first transport mechanism 31 are longer than the natural length (natural circumferential length) L0. In this way, the pulley 69 can be rotated via the pulley 66b by the tension of the belt 68. Further, the belt circumferential length L1 corresponding to the closed state, that is, the nipping conveyance of the recording material P can be set within the recommended extension range which is the optimum tension. The belt circumferential length L2 in the open state may be outside the recommended extension range as long as it is greater than L0.

  On the other hand, the rotation shaft 132 for rotating the first transport mechanism 31 is disposed in front of the transport mechanism with respect to the belt 68 and on the back side of the second transport mechanism 32. The pulley 69 is fixed to the first transport mechanism 31 and the pulley 66b is fixed to the second transport mechanism. Therefore, as shown by the broken line in FIG. 9B, when the first transport mechanism 31 is rotated around the rotation shaft 132 and opened, the circular surface of the pulley 69 and the pulley 66b both facing the same direction. Circular surfaces are close to each other. In this example, the driving pulley 66b is fixed and does not move when the first transport mechanism 31 rotates, and the driven pulley 69 moves. As a result, the distance between the pulley 69 and the pulley 66b is shortened, and the circumferential length of the belt 68 is also displaced from L1 to L2 (L1> L2).

  In other words, if the center of the pulley 69 and the pulley 66b is on the XY plane in FIG. 9B and the center of the pulley 66b is at the origin, the pulley 69 is simply opened when the first transport mechanism 31 is opened. It does not move in the XY plane, but also moves in the Z direction orthogonal to the XY plane. The movement of the pulley 69 is not a simple rotational movement in the XY plane centered on the pulley 66b, in which the distance between the pulleys does not change. This shortens the distance between the pulley 69 and the pulley 66b (L1> L2). Further, in order to satisfy the condition of L1> L2, the drive transmission belt 68 is provided on the rear side of the apparatus with respect to the rotation shaft 132, and when the first transport mechanism 31 is opened, the drive transmission belt 68 is on the rear side of the apparatus. It is also necessary to move to.

  At this time, in order to prevent the belt 68 from being detached from the pulleys 69 and 66b, it is preferable to set the circumference of the belt 68 in the open state indicated by the broken line so as to be within the recommended extension range. That is, it is preferable that LA ≦ L2 ≦ LB holds.

  Thus, by setting the belt 68 to be longer when the first transport mechanism 31 is closed than when the first transport mechanism 31 is opened, in the closed state, the driven roller 55a is driven via the drive shaft of the drive roller 57a. While driving can be transmitted to the rotating shaft, the belt 68 can be prevented from being detached from the pulleys 69 and 66b in the open state.

  In setting the belt circumference, it is more preferable to set the belt circumference in the open state of the first transport mechanism 31 to be larger than the minimum value of the recommended extension range in consideration of the deterioration of the belt with time. In consideration of this, it is more preferable to make the belt circumferential length in the closed state of the first transport mechanism 31 larger than the median value of the recommended extension range.

31 First transport mechanism 32 Second transport mechanism 61 Drive motor (drive means)
68 Drive transmission belt 132 Rotating shaft

JP 2012-98677 A JP 2010-2644 A JP 2002-351230 A

Claims (8)

A first transport mechanism and a second transport mechanism facing each other capable of sandwiching and transporting a recording material;
Drive means for rotationally driving the drive shaft of the second transport mechanism;
Extendable drive transmission that connects the rotation shaft of the first transport mechanism and the drive shaft of the second transport mechanism to transmit the drive of the second transport mechanism to the rotation shaft of the first transport mechanism Belt,
A rotation shaft for opening and closing the first transport mechanism in an open state and a closed state;
2. A recording material conveying apparatus according to claim 1, wherein the circumference of the drive transmission belt is longer in the closed state than in the open state of the first conveying mechanism. The first pulley is provided on the second transport mechanism side, the second pulley is provided on the first transport mechanism side, and the drive transmission belt is wound around the first pulley and the second pulley,
2. The recording material conveyance according to claim 1, wherein when the first conveyance mechanism is rotated around the rotation axis and opened, the circular surfaces of the first pulley and the second pulley are close to each other. apparatus.   The circumference of the drive transmission belt in the open state and the closed state is both longer than the natural circumference of the drive transmission belt, and the circumference of the drive transmission belt in the closed state is within a recommended extension range. The recording material conveying apparatus according to claim 1 or 2.   The recording material transport apparatus according to claim 2, wherein the first pulley is fixed to a drive shaft of the second transport mechanism.   The recording material conveying apparatus according to claim 1, wherein the drive transmission belt is a round belt having a natural length and a substantially circular cross section.   6. The drive transmission belt is provided on the rear side of the apparatus with respect to the rotation shaft, and when the first transport mechanism is opened, the drive transmission belt moves to the rear side of the apparatus. The recording material conveying apparatus according to any one of the above.   The first transport mechanism and the second transport mechanism include a transport belt, a stretching member that stretches the transport belt, and a cooling member that contacts the inner periphery of the transport belt and absorbs heat of the recording material. The recording material conveying apparatus according to claim 1, wherein the recording material conveying apparatus is a recording medium conveying apparatus.   An image forming apparatus comprising: an image forming unit that forms an image on the recording material; and the recording material conveying device according to claim 1 that conveys the recording material after image formation.

Images