JP2005274824A - Carrying roller driving mechanism and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carrying roller driving mechanism that enables thermal development of high precision and is small-sized and advantageous in cost and an image forming apparatus using the same. <P>SOLUTION: Disclosed is the carrying roller driving mechanism 50 which carries a sheet type carried body by putting the carried body between carrying rollers driven by a motor 58 to rotate and a guide member 53 arranged opposite the carrying rollers 51 and 52, the carrying roller driving mechanism 50 being characterized in that the motor 58 is a pulse motor and power is transmitted to the carrying rollers 51 and 52 through high-Young's modulus resin-based belts 59 and 60 whose elongation is ≤0.07 with a load of 10 N. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transport roller driving mechanism that is rotationally driven by a motor and an image forming apparatus using the transport roller drive mechanism, and more particularly to a technique for stabilizing the transport speed without being affected by disturbance.

  In recent years, in the medical field, reduction of waste processing liquid has been strongly desired from the viewpoint of environmental protection and space saving. Therefore, photosensitive thermal development for medical diagnosis and photographic technology that can be efficiently exposed by a laser image setter or laser imager and can form a clear black image having high resolution and sharpness. There is a need for technology relating to photographic materials. These photosensitive heat-developable photographic materials eliminate the use of solution processing chemicals, and can supply a heat-development processing system that is simpler and does not affect environmental considerations to the market.

  Therefore, in recent years, a recording apparatus using a dry system that does not require wet processing has attracted attention. In such a recording apparatus, a photosensitive and heat-sensitive recording material (photosensitive heat-sensitive recording material) or a heat-developable photosensitive material film is used. Hereinafter, this material is referred to as “heat-developable recording material” or “heat-developable photosensitive material”. In the recording apparatus using the dry system, a latent image is formed by irradiating (scanning) the heat-developable recording material with a laser beam in the exposure unit, and then the heat-developable recording material is brought into contact with the heating unit in the heat developing unit. Thermal development is performed, and then cooling is performed, and the thermally developed recording material on which an image is formed is discharged out of the apparatus. Such a dry system can solve the problem of waste liquid treatment as compared with wet treatment.

  As an example of a conventional transport roller drive mechanism, a transport roller drive mechanism that transmits the rotational force of a DC motor using a polyimide resin belt (kapton belt) is known (for example, see Patent Document 1).

  As shown in FIG. 6, in the conveyance roller driving mechanism 100 disclosed in Patent Document 1, a rotating body 103 is coupled to a motor shaft 102 of a DC motor 101, and the rotating body 103 and the conveyance roller 104 are coupled concentrically. The pulley 105 is connected by a resin belt 106 made of polyimide.

In such a transport roller driving mechanism 100, a guide plate 107 is disposed facing the transport roller 104, and the transport roller 104 is rotated by the rotational force of the DC motor 101. Thus, the heat development recording material 108 is sandwiched between the transport roller 104 and the guide plate 107 and proceeds in the sub-scanning direction, and laser light is irradiated from the main scanning direction.
JP 2004-004279 A

Incidentally, in Patent Document 1, there is a predetermined gap between the conveying roller 104 and the guide plate 107. However, as shown in FIG. 7, when the heat-developable recording material 106 is sandwiched between the conveying roller 104 and the guide plate 107, it is conveyed from a position “a” where the leading end of the heat-developable recording material 106 contacts the conveying roller 104. There is a moment when the driving torque of the conveying roller 104 becomes particularly large between the position away from the roller 104 and the non-contact position b. This is the moment when the heat-developable recording material 106 is sandwiched between the conveyance rollers 104. At this time, the driving torque of the conveying roller 104 increases momentarily, so that the resin belt 106 extends and the scanning speed of the heat-developable recording material 106 changes. As a result, an image formed on the heat-developable recording material 106 has a defect.
Therefore, it is conceivable to use a metal belt instead of the resin belt 106. However, although the belt is less stretched, the service life is short, and since it is a metal, the arrangement of the belt is restricted. Therefore, it is difficult to say that a metal belt is a preferable belt from the viewpoint of maintainability and design freedom.

  On the other hand, there is a transport roller driving mechanism using a planetary gear mechanism in order to mechanically stabilize the scanning speed of the heat-developable recording material. As shown in FIG. 8, in the planetary gear mechanism 110, when the pulley 111 to which power is transmitted via the belt rotates, the planetary gears 112a, 112b, and 112c meshed with the pulley 111 are relatively moved. Rotating, the gear 113 meshed with the planetary gears 112a, 112b, 112c is rotated, and the transport roller is rotated. However, in such a planetary gear mechanism 110, there is a limit to the reduction ratio, and in order to decelerate the rotation of the DC motor that rotates at high speed to match the scanning speed of the heat-developable recording material, multiple stages of deceleration are required. As a result, a plurality of planetary gear mechanisms 110 are arranged, and the outer shape of the transport roller driving mechanism is increased. Moreover, since the planetary gear mechanism 110 is expensive, it is disadvantageous in terms of cost.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transport roller drive mechanism that can perform heat development with high accuracy and is small and advantageous in terms of cost, and image formation using the transport roller drive mechanism. To provide an apparatus.

  In order to achieve the above object, a transport roller driving mechanism according to claim 1 of the present invention is a sheet-like structure between a transport roller that is rotationally driven by a motor and a guide member that is disposed to face the transport roller. A high-modulus resin belt having a conveyance roller driving mechanism that sandwiches and conveys the object to be conveyed, wherein the motor is a pulse motor, and the conveyance roller has an elongation of 0.07% or less with respect to a load of 10N. It is characterized in that power is transmitted through the.

  According to this transport roller driving mechanism, the transport roller is driven using a high Young's modulus resin belt having an elongation of 0.07% or less with respect to a load of 10N. Therefore, it is possible to eliminate unevenness in the rotation speed of the transport roller, that is, the transport speed of the transported object.

  The transport roller drive mechanism according to claim 2 is the transport roller drive mechanism according to claim 1, wherein the guide plate includes a flat portion along the transport direction of the transported body and an inclined portion bent toward the transport roller. It is characterized by having.

  According to this transport roller driving mechanism, the guide plate bends the transport target inserted between the transport rollers by the inclined portion along the part of the peripheral surface of the transport roller on the outside between the transport rollers. Thus, the elastic repulsive force due to the bending of the transported body is brought into contact with and received between the transport rollers. In other words, when the transported body enters from the tip of the inclined portion, the tilted portion of the guide plate is bent when the tip of the transported body enters between the guide plate and the transport roller. It bends as it travels through the inclined portion, and due to this bending, an elastic repulsive force is generated in the conveyed object itself. Due to this elastic repulsive force, a predetermined frictional force is generated between the conveyed object and the conveying roller, and the conveying driving force is reliably transmitted from the conveying roller to the conveyed object, so that the conveyed object is conveyed with high accuracy.

  The conveyance roller drive mechanism according to claim 3 is the conveyance roller drive mechanism according to claim 1 or 2, wherein a reduction means for decelerating the rotation speed of the motor is interposed between the motor and the conveyance roller. The decelerating means includes a first decelerating portion disposed on one end side of the conveying roller and a second decelerating portion disposed on the other end side.

  According to this transport roller drive mechanism, since the first and second speed reducers are divided and arranged on one end side and the other end side of the transport roller drive mechanism, the vibration of the motor is suppressed. The number of rotations can be set. Further, by adopting a two-stage deceleration, it is possible to prevent uneven rotation of the motor and to rotate the transport roller in a stable rotation region.

  The image forming apparatus according to claim 4 is an image forming apparatus that performs image formation on the photosensitive recording material by irradiating the photosensitive recording material with laser light while conveying the sheet-shaped photosensitive recording material. The conveyance roller driving mechanism according to any one of claims 1 to 3, and the photosensitive recording material on the guide member of the conveyance roller driving mechanism is irradiated with laser light modulated based on image data. And a laser irradiation unit for scanning.

  According to this image forming apparatus, the conveyance speed of the photosensitive recording material is uniform, and the conveyance roller driving mechanism that can convey the photosensitive recording material with high accuracy by rotating the conveyance roller in a stable rotation region is used. As a result, it is possible to form a highly accurate image with no exposure position shift.

  According to the transport roller driving mechanism and the image forming apparatus using the same according to the present invention, the transport speed fluctuates due to disturbance, the outer shape of the transport roller driving mechanism becomes large, and the cost is disadvantageous. As a result, image defects are less likely to occur in the formed image, and the configuration is small and advantageous in terms of cost.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a conveyance roller driving mechanism and an image forming apparatus using the same according to the invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an image forming apparatus using a transport roller driving mechanism according to the present invention, FIG. 2 is a detailed explanatory view of an image exposure unit of the image forming apparatus shown in FIG. 1, and FIG. 4 is a side view from the direction A of FIG. 3, and FIG. 5 is a side view from the direction B of FIG.

First, the structure and operation of the image forming apparatus will be described.
As shown in FIG. 1, an image forming apparatus 10 according to an embodiment of the present invention uses a heat-developable recording material that does not require wet development processing, and performs heat-developable recording material by scanning exposure using a light beam composed of laser light. Is exposed to light to form a latent image, followed by heat development to obtain a visible image, and then cooled to room temperature.

  The image forming apparatus 10 basically includes a heat development recording material supply unit A, an image exposure unit (corresponding to the laser recording device 11) B, a heat development unit C, in the order of conveyance of the heat development recording material. A cooling unit D, and a transport unit for transporting the heat-developable recording material provided at a key point between the units, and a power source / control unit E that drives and controls the units. The image forming apparatus 10 has a configuration in which a power supply / control unit E is disposed at the bottom, a heat development recording material supply unit A is disposed at the top, and an image exposure unit B, a heat development unit C, and a cooling unit D are disposed at the top. The image exposure part B and the heat development part C are arranged adjacent to each other. According to this configuration, the exposure process and the heat development process can be performed within a short transport distance, the transport path length of the heat development recording material can be minimized, and the output time of one sheet can be shortened. In addition, both the exposure process and the thermal development process can be simultaneously performed on one thermal development recording material.

  As the heat-developable recording material, a heat-developable photosensitive material or a photosensitive heat-sensitive recording material can be used. The photothermographic material is a recording material that records an image (scanning exposure) with a light beam (for example, a laser beam) and then develops it by heat development. In addition, the photosensitive and heat-sensitive recording material records an image with a light beam and then develops it by heat development, or develops a color simultaneously with recording an image by a heat mode (heat) of a laser beam, and then irradiates with light. It is a recording material to be fixed.

  The heat-developable recording material supply unit A is a part that takes out the heat-developable recording material one by one and supplies it to the image exposure unit B located downstream in the conveyance direction of the heat-developable recording material. , 14, supply roller pairs 15, 16, and 17 disposed in each loading unit, and a conveyance roller and a conveyance guide (not shown). Further, magazines 18, 19, and 20 in which different types of heat-developable recording materials (for example, B4 size, half-cut size, etc.) are accommodated inside the loading sections 12, 13, and 14 having a three-stage configuration. Is inserted so that one of the sizes and orientations loaded in each stage can be used selectively.

  The heat-developable recording material is processed into a sheet shape, and is usually formed into a laminated body (bundle) of a predetermined unit such as 150 sheets, and is packaged by a bag or a belt. Each package is housed in a magazine and loaded in each stage of the heat-developable recording material supply unit A.

  The image exposure unit B scans and exposes the heat-developable recording material conveyed from the heat-developable recording material supply unit A with the light beam L in the main scanning direction, and also in a sub-scanning direction (substantially orthogonal to the main scanning direction ( That is, by transporting in the transport direction), a desired image is recorded on the heat-developable recording material to form a latent image.

  The thermal development unit C performs thermal development by performing a temperature rise process while conveying the thermal development recording material after scanning exposure. Then, the heat-developable recording material after the development processing is cooled in the cooling unit D and carried out to the discharge tray 21.

Here, the image exposure unit B which is the laser recording apparatus 11 will be specifically described.
FIG. 2 is a configuration diagram showing a schematic configuration of a sub-scanning conveyance unit and a scanning exposure unit for conveying a sheet-like thermally developed recording material in the laser recording apparatus 11.
The image exposure unit B, which is the laser recording apparatus 11, is a part that exposes the heat-developable recording material by light beam scanning exposure, and has a sub-fluctuation preventing mechanism that conveys the heat-developable material while preventing flapping from the conveyance surface. A scanning conveyance unit (sub-scanning unit) 22 and a scanning exposure unit (laser irradiation unit) 23 are provided. The scanning exposure unit 23 scans (main scans) the laser while controlling the output of the laser in accordance with separately prepared image data. At this time, the heat-developable recording material is moved in the sub-scanning direction by the sub-scanning conveyance unit 22.

  The sub-scanning conveyance unit 22 includes a conveyance roller driving mechanism 50, and two conveyance rollers 51 and 52 having an axis line disposed substantially parallel to the scanning line with a main scanning line of the laser beam to be irradiated interposed therebetween. And a guide plate 53 that is disposed so as to face the transport rollers 51 and 52 and supports the heat-developable recording material 90. The guide plate 53 bends the heat-developable recording material 90 inserted between the transport rollers 51 and 52 along a part of the peripheral surface of the transport roller outside the parallel transport rollers. The inclined portions 54 and 55 and the pressing portion 57 formed of a substantially horizontal flat portion 56 that receives and receives the elastic repulsion force due to the bending of the heat-developable recording material 90 between the conveying rollers are formed.

  The transport roller 51 receives the driving force of a pulse motor (shown in FIG. 3) 58 via two high Young's modulus resin belts 59 and 60 (shown in FIG. 3), and rotates in the clockwise direction of FIG. It is supposed to be. A transport roller 52 having the same configuration as the transport roller 51 is provided for discharging the heat-developable recording material 90 at the boundary position between the inclined portion 55 and the pressing portion 57.

On the other hand, the scanning exposure unit 23 deflects the laser light L modulated in accordance with the image signal in the main scanning direction and enters the predetermined recording position X, and corresponds to the spectral sensitivity characteristic of the heat-developable recording material. In addition, a laser light source 24 that emits laser light (wavelength 350 nm to 900 nm) in a narrow band wavelength range, a recording control device 25 that drives the laser light source 24, a cylindrical lens 26, a polygon mirror 27 that is an optical polarizer, and fθ. A lens 28 and a cylindrical mirror 29 for falling are provided.
In addition, the scanning exposure unit 23 includes other known light beam scanning exposures such as a collimator lens, a beam expander, a surface tilt correction optical system, and an optical path adjustment mirror that shape the light beam emitted from the laser light source 24. Various optical system members arranged in the apparatus are arranged as necessary. The recording beam diameter of the laser beam on the heat-developable recording material 90 is set to φ50 to φ200 μm. In particular, the recording beam diameter in the sub-scanning direction is preferably small in order to reduce the interference area.

  Here, a direct modulation method is employed as the exposure method, and image recording is performed thereby. The recording control device 25 directly modulates and drives the laser light source 24 according to the recorded image, and emits a light beam directly modulated according to the recorded image. The laser light L emitted from the laser light source 24 is deflected in the main scanning direction by the polygon mirror 27, adjusted so as to form an image at the recording position X by the fθ lens 28, and the optical path is selected by the cylindrical mirror 29 for recording. The light enters the position X at a predetermined incident angle θi. That is, an incident angle having an inclination of 4 ° to 15 ° from the normal of the heat-developable recording material 90 to the sub-scanning direction in a plane parallel to the normal direction of the heat-developable recording material 90 and the sub-scanning direction (conveyance direction). The laser beam L is irradiated toward the heat-developable recording material 90 at θi.

  In the image forming apparatus 10, image data from an image data supply source R such as CT or MRI is sent to the image processing unit 30. The image processing unit 30 is a combination of various image processing circuits and memories, and includes a density correction unit that performs density correction and a data processing unit that performs various image processes such as sharpness correction. Then, the image data (image information) from the image data supply source R is received, and various corrections and processes are performed to obtain thermal recording image data corresponding to the thermal recording. Further, the measurement value correction unit of the built-in densitometer 31 is connected to the density correction unit.

Next, the heat developing unit C will be described.
The heat development section C heats a heat-treated heat-developable recording material of a type to which heat treatment is applied, and has a configuration necessary for processing the heat-developable recording material 90 as shown in FIG. A plurality of plate heaters 32, 33, and 34 arranged in the transfer direction of the heat-developable recording material are used as the heating body, and the surfaces on the side to heat these heat-developable recording materials 90 are curved, and these plate heaters 32, 33, and 34 are arranged in a series of circular arcs.

  That is, as shown in the figure, the heat developing section C including the plate heaters 32, 33, and 34 is provided with a concave surface, and the heat development recording material 90 is brought into contact with the concave surface of the plate heater. Slide it while moving it relatively. At this time, a supply roller 35 and a plurality of pressing rollers 36 that are also used for heat transfer from each plate heater to the heat development recording material 90 are provided as means for transferring the heat development recording material 90. The pressing roller 36 is driven to rotate following the rotation of a gear 41 provided at the end of the shaft. As these pressing rollers 36, a metal roller, a resin roller, a rubber roller, or the like can be used. With this configuration, since the heat-developable recording material 90 being conveyed is conveyed while being pressed against the plate heaters 32, 33, 34, buckling of the heat-developable recording material 90 can be prevented. A discharge roller pair 37 for transferring the heat-developable recording material 90 is disposed at the end of the conveyance path of the heat-developable recording material 90 in the heat developing portion C.

  Of course, the curved plate heater is an example, and may be configured to include an endless belt and a peeling claw using another flat plate heater or a heating drum.

  The heat-developable recording material 90 carried out from the heat-developing part C is cooled with care so that no wrinkles are generated by the cooling part D and no curling occurs. The heat-developable recording material 90 discharged from the heat-development section C is guided into the guide plate 40 by the cooling roller pairs 38 and 39 provided in the middle of the conveyance path, and is further discharged from the discharge roller pair 37 to the discharge tray 21. The

Thus, in the cooling section D, a plurality of cooling roller pairs 38 and 39 are arranged so as to give a desired constant curvature (r) to the conveyance path of the heat-developable recording material 90. This means that the heat-developable recording material 90 is conveyed with a constant curvature (r) until it is cooled below the glass transition point of the material, and thus the heat-developable recording material is intentionally curved. Thus, extra curl is not generated before the glass transition point is cooled below the glass transition point, and if it is lower than the glass transition point, no new curl is attached and the curl amount does not vary.
Further, the cooling roller itself and the cooling unit D adjust the temperature of the internal atmosphere. Such temperature adjustment makes it possible to make the conditions immediately after starting up the heat treatment apparatus and after sufficiently running as much as possible to reduce the concentration fluctuation.

  Between the guide plate 40 and the discharge roller pair 37, a built-in densitometer 31 for detecting the image density of the heat-developable heat-developable recording material 90 is provided. The built-in densitometer 31 is basically composed of a light emitting light source and a received light amount detection unit, detects the light amount by a light receiving element, converts the detected light amount into a corresponding electric signal, and outputs it.

  The image recording on the heat-developable recording material 90 is described in detail in, for example, International Publication No. WO95 / 31754 and International Publication No. WO95 / 30934, and is referred to as necessary. I want.

  Next, the transport roller driving mechanism 50 will be described in detail with reference to FIGS.

  As shown in FIGS. 3, 4, and 5, the conveyance roller drive mechanism 50 includes a pulse motor 58, a first reduction part 61 including a high Young's modulus resin belt 59, a connecting shaft 62, and a high Young's modulus. The second speed reducing unit 63 including the system resin belt 60, two transport rollers 51 and 52, and a guide plate 53 are configured. The first speed reduction unit 61 is disposed on one end side of the transport roller driving mechanism 50, and the second speed reduction unit 63 is disposed on the other end side of the transport roller driving mechanism 50. The two transport rollers 51 and 52 are rotatably supported by the guide plate 53.

  The pulse motor 58 is a so-called stepping motor, and is driven by a current supplied in a pulse form from a drive circuit (not shown). The pulse motor 58 has a high torque characteristic. The pulse motor 58 is screwed to the bracket 64 on the first speed reduction unit 61 side, and a first pulley 65 constituting a part of the first speed reduction unit 61 is concentrically coupled to a motor shaft (not shown). Has been.

  The first speed reduction unit 61 includes a first pulley 65, a high Young's modulus resin belt 59, and a second pulley 66.

  The high Young's modulus resin belt 59 is an endless belt (timing belt) formed with glass fiber as a core, neoprene rubber as tooth rubber, and nylon canvas as a tooth surface cover. When a force of 10 N is applied. Elongation of 0.07% or less. The high Young's modulus resin belt 59 is stretched around the first pulley 65 and the second pulley 66.

  In the first speed reduction unit 61, a tension roller 67 is disposed between the first pulley 65 and the second pulley 66. The tension roller 67 is rotatably supported at the tip portion of the first tensioner 68. Since the first tensioner 68 is rotatably attached to the bracket 64, the tip portion is pulled downward in FIG. 3, so that the tension roller 67 is placed inside the high Young's modulus resin belt 59. The tension of the high Young's modulus resin belt 59 is adjusted in contact with the peripheral surface.

  The first speed reduction unit 61 rotates the second pulley 66 by reducing the rotation of the motor shaft of the pulse motor 58 by the first pulley 65 and the second pulley 66.

  One end of the connecting shaft 62 is fixed concentrically to the second pulley 66 of the first reduction gear 61, and the other end is fixed concentrically to a third pulley 69 provided in the second reduction gear 63. .

  The second deceleration unit 63 includes a third pulley 69, a high Young's modulus resin belt 60, and fourth and fifth pulleys 70 and 71.

  The high Young's modulus resin belt 60 is an endless belt that is the same as the high Young's modulus resin belt 59 of the first reduction gear 61, and includes a third pulley 69 and fourth and fifth pulleys 70 and 71. It is being handed over. The fourth and fifth pulleys 70 and 71 are concentrically coupled to the transport rollers 51 and 52, respectively. The conveyance rollers 51 and 52 are rotatably supported at both ends of the guide plate 53.

  In the second speed reducing unit 61, a tension roller 72 is disposed between the third pulley 69 and the fourth and fifth pulleys 70 and 71. The tension roller 72 is rotatably supported at the tip of the second tensioner 73. Since the second tensioner 73 is rotatably attached to a second bracket (not shown), the tip end portion is pulled downward in FIG. The tension of the high Young's modulus resin belt 60 is adjusted by contacting the inner peripheral surface of the resin belt 60.

  The second speed reducer 63 decelerates the rotation of the connecting shaft 62 by the third pulley 69 and the fourth and fifth pulleys 70 and 71 to rotate the transport rollers 51 and 52.

  Since the first and second speed reducers 61 and 63 are arranged separately on one end side and the other end side of the transport roller driving mechanism 50, the vibration of the pulse motor 58 is suppressed so as to suppress the vibration of the pulse motor 58. The number of rotations can be set. Further, the final reduction ratio is set to 1/14 as two-stage reduction. Therefore, the rotation unevenness of the pulse motor 58 is also prevented, and the transport rollers 51 and 52 can be rotated in the most stable rotation region (3 rps, sub-scanning speed 18.08 mm / s).

Further, since the first and second speed reducing portions 61 and 63 use high Young's modulus resin belts 59 and 60 whose elongation when a force of 10 N is applied is 0.07% or less, There is no unevenness in the rotation speed of the rollers 51, 52, that is, the conveyance speed. Moreover, there is no slip with the conveyance rollers 51 and 52. Here, the vibration of a normal belt including the high Young's modulus resin belts 59 and 60 is the belt shape, the natural frequency of the belt determined by the Young's modulus, the inter-axis distance, the pulley diameter, the duty cycle, and the rotation. It is known that resonance occurs when the number of vibrations determined from the attachment or the attachment mechanism, such as the number, becomes an integral multiple.
As a factor of belt vibration, the belt's Young's modulus, belt's second moment, belt's cross-sectional area, belt's density, belt speed The distance between the shafts and the tension applied to the belt can be mentioned.
Also, the vibration factors include mass imbalance in the belt length direction, pulley runout, belt tension fluctuation due to load load, belt tension fluctuation due to pulley rotation speed, other vibrators on the machine Propagation vibration due to, etc. can be considered. Therefore, the dimensions and materials of each part are selected and adopted so as to avoid these factors.

  In the following, including FIG. 2, the conveying roller 51 is decelerated by the first and second decelerating portions 61 and 63 and rotates in the clockwise direction in FIG. 6. It is provided for discharging the heat-developable recording material 90 at the boundary position with the pressing portion 57, is decelerated by the first and second decelerating portions 61 and 63, and rotates in the clockwise direction in FIG. The heat-developable recording material 90 inserted between the conveyance rollers 51 and 52 is bent along a part of the circumferential surface of the conveyance roller by the inclined portions 54 and 55 of the guide plate 53, and is heated by the flat portion 56 of the guide plate 53. It proceeds in the sub-scanning direction while receiving and receiving the elastic repulsion force caused by the bending of the development recording material 90.

  The inclined portion 54 is an inclined surface that is bent and connected at a boundary portion with the pressing portion 57, and an intersection angle φ between the inclined portion 54 and the pressing portion 57 is in a range of 0 ° to 45 ° (see FIG. 2). Further, the inclined portion 55 on the downstream side of the conveyance is formed in the same manner, and the inclined surface with the intersecting angle φ is provided with respect to the pressing portion 57. The inclined surface bent at an intersection angle φ greater than 0 ° may be provided at least on the upstream side in the transport direction.

  Here, the conveyance roller 51 will be described as an example. The conveyance roller 51 is disposed so as to face a bent portion 75 that is a boundary portion between the pressing portion 57 and the inclined portion 54. The arrangement position of the conveyance roller 51 with respect to the guide plate 53 passes through a bent portion (angle change point) 75 of the guide plate 53, and a straight line that bisects the inner angle (180 ° −φ) of the guide 53 plate, and the conveyance roller 51. It is preferable that it is the range which the outer periphery contacts. There are no particular restrictions on the relationship between the diameter of the transport roller 51 and the length of the guide plate 53.

  Further, the transport roller 51 is arranged such that a predetermined gap G is formed between the peripheral surface and the guide plate 53. The gap G is preferably the same or ten times as thick as the thickness t of the heat-developable recording material 90 (t ≦ G ≦ 10t).

  As shown in FIG. 6, in the transport roller driving mechanism 50, when the heat development recording material 90 enters from the front end of the inclined portion 54, the front end of the heat development recording material 90 enters between the guide plate 53 and the transport roller 51. At this time, since the pressing portion 57 and the inclined portion 54 of the guide plate 53 are bent at a predetermined angle φ, the heat-developable recording material 90 is bent when it moves from the inclined portion 54 to the pressing portion 57. As a result, an elastic repulsive force is generated in the heat-developable recording material 90 itself. Due to this elastic repulsive force, a predetermined frictional force is generated between the heat-developable recording material 90 and the transport roller 51, and the transport driving force is reliably transmitted from the transport roller 51 to the heat-developable recording material 90. Is transported.

  When the heat-developable recording material 90 enters between the guide plate 53 and the conveyance roller 51, the gap G between the conveyance roller 51 and the guide plate 53 driven clockwise is the thickness dimension of the heat-developable recording material 90. Since t is set to t to t, vibrations of the conveyance roller 51 due to disturbance do not affect the conveyance of the heat-developable recording material 90. That is, when the disturbance occurs, it is absorbed by the elastic force (displacement in the thickness direction) of the heat-developable recording material 90, so that the conveyance is not affected.

  Further, even when the heat development recording material 90 is discharged from the guide plate 53 by the inclined portion 54 and the conveyance roller 52, a predetermined frictional force is generated between the conveyance roller 52 and the elastic roller due to the elastic repulsion due to the bending of the heat development recording material 90. Occurs, and it is reliably conveyed.

  In the pressing portion 57, the heat-developable recording material 90 is pressed against the pressing portion 57 by the elastic repulsive force of the heat-developable recording material 90, and flutters from the conveying surface of the heat-developable recording material 90, that is, the vertical direction. Fluttering is suppressed. By irradiating the heat-developable recording material 90 between the drive rollers with laser light in the main scanning direction, good recording without deviation of the exposure position can be performed.

  As described above, according to the transport roller driving mechanism 50, the transport rollers 51 and 52 are driven using the high Young's modulus resin belts 59 and 60 having an elongation of 0.07% or less with respect to a load of 10N. The Accordingly, it is possible to eliminate unevenness in the rotation speed of the transport rollers 51 and 52, that is, the transport speed of the heat-developable recording material 90.

  Further, according to the transport roller driving mechanism 50, the guide plate 53 transports the heat-developable recording material 90 inserted between the transport rollers 51 and 52 by the inclined portions 54 and 55 on the outer side between the transport rollers 51 and 52. The rollers 51 and 52 are bent along a part of the circumferential surface, and the flat portion 56 receives and receives the elastic repulsion force due to the bending of the heat-developable recording material 90 between the conveying rollers 51 and 52. That is, when the heat-developable recording material 90 enters from the front end of the inclined portion 54, the inclined portion 54 of the guide plate 53 is moved when the front end of the heat-developable recording material 90 enters between the guide plate 53 and the conveying rollers 51 and 52. Is bent, the heat-developable recording material 90 bends as it travels through the inclined portion 54, and this bend causes an elastic repulsive force to the heat-developable recording material 90 itself. Due to this elastic repulsive force, a predetermined frictional force is generated between the heat-developable recording material 90 and the transport rollers 51 and 52, and the transport driving force is reliably transmitted from the transport rollers 51 and 52 to the heat-developable recording material 90. The development recording material 90 is conveyed with high accuracy.

  Further, according to the transport roller driving mechanism 50, the first and second speed reduction units 61 and 63 are arranged separately on one end side and the other end side of the transport roller driving mechanism 50, so The rotation speed of the pulse motor 58 can be set so as to suppress vibration. Further, by adopting two-stage deceleration, it is possible to prevent uneven rotation of the pulse motor 58 and to rotate the transport rollers 51 and 52 in a stable rotation region.

  According to the image forming apparatus 10, there is no unevenness in the conveyance speed of the heat-developable recording material 90, and the conveyance rollers 51 and 52 are rotated in a stable rotation region so that the heat-developable recording material 90 can be accurately conveyed. By using the transport roller drive mechanism 50 that can be used, it is possible to form a highly accurate image without exposure position deviation.

1 is a schematic configuration diagram of an image forming apparatus using a conveyance roller driving mechanism according to the present invention. FIG. 2 is a detailed explanatory diagram of an image exposure unit of the image forming apparatus shown in FIG. 1. It is an external appearance perspective view of a conveyance roller drive mechanism. It is a side view from the A direction of FIG. It is a side view from the B direction of FIG. It is the schematic of the conventional conveyance roller drive mechanism. It is a drive torque characteristic figure of the conventional conveyance roller mechanism. It is sectional drawing of the planetary gear mechanism used for the conveyance roller drive mechanism different from FIG.

Explanation of symbols

10 Image forming apparatus 23 Scanning exposure unit (laser irradiation unit)
DESCRIPTION OF SYMBOLS 50 Conveyance roller drive mechanism 51,52 Conveyance roller 53 Guide member 54,55 Inclination part 56 Plane part 58 Pulse motor (motor)
59, 60 High Young's modulus resin belt 61 First reduction part (reduction means)
63 2nd deceleration part (deceleration means)
90 Thermal development recording material (conveyed material, photosensitive recording material)

Claims (4)

A transport roller drive mechanism for transporting a sheet-shaped transport target body sandwiched between a transport roller that is rotationally driven by a motor and a guide member that is disposed opposite the transport roller;
The motor is a pulse motor;
A conveying roller driving mechanism, wherein the conveying roller is transmitted with power through a high Young's modulus resin belt having an elongation of 0.07% or less with respect to a load of 10N.   The transport roller driving mechanism according to claim 1, wherein the guide plate has a flat portion along a transport direction of the transported body and an inclined portion bent toward the transport roller. A speed reduction means for reducing the rotational speed of the motor is interposed between the motor and the transport roller,
3. The transport according to claim 1, wherein the speed reducing means comprises a first speed reducing portion disposed on one end side of the transport roller and a second speed reducing portion disposed on the other end side. Roller drive mechanism. An image forming apparatus that forms an image on a photosensitive recording material by irradiating the photosensitive recording material with a laser beam while conveying the photosensitive recording material in a sheet form,
The conveyance roller drive mechanism according to any one of claims 1 to 3,
An image forming apparatus comprising: a laser irradiation unit configured to irradiate and scan the photosensitive recording material on the guide member of the transport roller driving mechanism with laser light modulated based on image data.

Images