Automatic document conveying device

Abstract: An automatic document conveying device (4) to be applied to an image processor (2) that has a transparent plate (8) disposed on the upper surface of a housing (6) so that a document to be processed is placed thereon. The automatic document conveying device comprises a document introduction portion (12), a main portion and a document delivery portion. The document introduction portion (12) includes an introduction portion frame member (18), a document table (20) that extends from the introduction portion frame member (18) toward the upstream side, a document introduction passage that extends from the document table (20) to the transparent plate (8) inside the introduction frame member (18), a document sending means for sending the document onto the document introduction passage from the document table, and a document introduction means for introducing onto the transparent plate the document sent onto the document introduction passage. The main portion includes a movable main portion frame member (70) that is mounted to move between a closed position for closing the transparent plate (8) and an open position for exposing the transparent plate (8) into view, and the document conveying means (74) that conveys the document along the transparent plate (8) when the movable main portion frame member (70) is at the closed position. The document conveying means (74) is constituted by a conveyer belt mechanism mounted on the movable main portion frame member. The document delivery portion (16) includes a delivery portion frame member (100), a document delivery passage defined within the delivery portion frame member, and a document delivery means that delivers the document onto the document receiving tray through the document delivery passage. The document delivery portion is provided with a document re-introduction passage that extends to the transparent plate being branched from the document delivery passage.

Description: The present invention relates to an automatic document conveying device adapted to an image processor such as an electrostatic copying machine or an image reader. It is widely accepted practice to provide image processing machines such as electrostatic copying machines and image readers with an automatic document conveying device in order to automatically handle the documents in the image copying operation or in the image reading operation. Prior literature disclosing automatic document conveying devices can be represented by Japanese Patent Laid-Open Publication Nos. 91747/1978 and 118551/1985, and Japanese Utility Model Laid-Open Publication No. 49348/1986. The image processing machine such as the electrostatic copying machine or the image reader has a housing, and on the upper surface of the housing is disposed a transparent plate on which will be placed a document that is to be processed. The automatic document conveying device is usually equipped with a document introduction portion, a main portion and a document delivery portion. The document introduction portion includes an introduction portion frame member disposed on the upstream side of the transparent plate and a document table that extends toward the upstream side from the introduction portion frame member. In the introduction portion frame member is formed a document introduction passage that extends from the document table toward the transparent plate. A plurality of pieces of documents placed on the document table are sent onto the document introduction passage piece by piece by the operation of document sending means, and are carried onto the transparent plate through the document introduction passage by the operation of document introduction means. The main portion of the automatic document conveying device includes a movable main portion frame member that is mounted to pivot between a closed position to cover the transparent plate and an open position to bring the transparent plate exposed to view, and document conveying means which conveys the document along the transparent plate when the movable main portion frame member is at the closed position. The document conveying means is usually constituted by a conveyor belt mechanism mounted on the movable main portion frame member. The document delivery portion includes a delivery portion frame member disposed on the downstream side of the transparent plate. In the delivery portion frame member is formed a document delivery passage. Further, a document re-introduction passage is often formed therein branched from the document delivery passage and extending toward the downstream end of the transparent plate. The document on the transparent plate is sent onto the document delivery passage, delivered through the document delivery passage by the operation of the document delivery means, and is discharged onto a document receiving tray, or is introduced into the document re-introduction passage from the document delivery passage and is re-introduced onto the transparent plate. The document receiving tray is disposed on the main portion or on the delivery portion. The published German application DE-A 36 26 846 discloses a document conveying device, the features of which have been used to form the preamble of claim 1. The device is adapted to convey a document along a transparent plate when its frame is located in a closed position for copying. The conveying device comprises a conveyor belt mechanism including front side and rear side support means as well as a driven roller and a follower roller provided between the support means. An endless belt is wound about and driven by the roller arrangement. The Patent Abstracts of Japan, Vol. 10, No. 301 (M-525) [2357], October 14, 1986 relating to JP-A 61-114944 discloses an automatic original feeder comprising a support frame for an original conveying unit. An endless conveyor belt is mounted on a system of pulleys including a drive pulley and a driven pulley, which provide conveyance of an original across the mount face of a copying machine. US-A 4 674 858 and GB-A 2,125,388 both disclose copying machines by which a recording member in the form of an endless belt of photoconductive material is mounted over a plurality of rollers for rotational drive of the recording member. The recording member can be selectively moved between a tensioned position and a position in which the tension is removed therefrom. Conventional conveying devices have the problem that the main portion of the automatic document conveying device is constituted by a conveyor belt mechanism that includes a driven roller and a follower roller disposed in the document conveying direction maintaining a distance, and an endless belt wound around these rollers. With such a conveyor belt mechanism, the endless belt must be renewed when it is fouled or is damaged. In the conventional automatic document conveying device, however, the operation for replacing the endless belt (operation for removing and mounting the belt) of the conveyor belt mechanism is not easy but is relatively complex. The object of the present invention is to provide an improved automatic document conveying device which greatly facilitates the operation for renewing the endless belt of the conveyor belt mechanism that constitutes the document conveying means in the main portion of the automatic document conveying device. According to the present invention, an automatic document conveying device is provided as defined in claim 1. Embodiments are given in claims 2 to 6. Other technical aspects of the present invention will become clear from the following detailed description. Fig. 1 is a perspective view which illustrates an automatic document conveying device mounted on an electrostatic copying machine under the condition where a central main portion thereof is at the closed position; Fig. 2 is a perspective view which illustrates the automatic document conveying device of Fig. 1 under the condition where the central main portion thereof is at the open position; Fig. 3 is a section view illustrating the automatic document conveying device of Fig. 1 under the condition where the central main portion thereof is at the closed position; Fig. 4 is a perspective view illustrating the support base member of central main portion in the automatic document conveying device of Fig. 1 and document conveying means (conveyor belt mechanism) mounted thereon; Fig. 5 is a perspective view illustrating, in a disassembled manner, the support base member of the central main portion in the automatic document conveying device of Fig. 1 and document conveying means (conveyor belt mechanism) mounted thereon; Fig. 6 is a plan view illustrating the support base member of the central main portion in the automatic document conveying device of Fig. 1 and document conveying means (conveyor belt mechanism) mounted thereon; Fig. 7-A and Fig. 7-B are partial side views showing the front-side support means of the document conveying means (conveyor belt mechanism) in the automatic document conveying device of Fig. 1 under the condition where the overall length thereof is extended (belt is stretched) and under the condition where the overall length thereof is contracted (belt is slackened); Fig. 8-A and Fig. 8-B are partial side views showing the rear-side support means of the document conveying means (conveyor belt mechanism) in the automatic document conveying device of Fig. 1 under the condition where the overall length thereof is extended (belt is stretched) and under the condition where the overall length thereof is contracted (belt is slackened); and Fig. 9 is a perspective view showing a cover member of the central main portion in the automatic document conveying device of Fig. 1. The automatic document conveying device constituted according to embodiments of the present invention and mounted on an electrostatic copying machine will now be described in detail with reference to the accompanying drawings. Overall Constitution Figs. 1, 2 and 3 illustrate an electrostatic copying machine 2 and an automatic document conveying device generally designated at 4 that is mounted on the electrostatic copying machine 2. The electrostatic copying machine 2 which per se may be of a known form is equipped with a nearly parallelopiped housing 6. A transparent plate (Figs. 2 and 3) made of a glass which may be of a rectangular shape is disposed at a central portion on the upper surface of the housing 6. A document placing-position restricting member 10 is disposed at one end edge of the transparent plate 8 (left end edge in Fig. 3). The document placing-position restricting member 10 extends in a direction perpendicular to the surface of the paper in Fig. 3 along one end edge of the transparent plate 8. Though not diagramed, in the housing 6 of the electrostatic copying machine 2 are disposed various constitutional elements including a rotary drum that has an electrostatic photosensitive member on the surface thereof. As is well known, the document to be copied is placed in the transparent plate 8 with its surface to be copied being faced downwards and its one end edge being contacted to an inside edge of the document placing-position restricting member 10 (right end edge in Fig. 3). The diagramed automatic document conveying device 4 is made up of a document introduction portion 12, a central main portion 14, and a document delivery and re-introduction portion 16. The document introduction portion 12 of the automatic document conveying device 4 is disposed on the upstream side of the transparent plate 8 (left side in Fig. 3) and abuts on the one end edge thereof. Here, constitutions of the document sending means 42 (document sending roller 46 and document separation roller pair 48), document introduction means 44 (upper roller 60 and lower roller 62) and placed document detector 66 do not constitute any novel features of the present invention and may be those of the forms known by people having ordinary skill, e.g., may be those of the forms disposed in the specification and drawings of Japanese Laid-Open Patent Publication No. 100939/1990 filed by the present applicant entitled "Automatic Document Conveying Device and Image Processing Machine Equipped Therewith". Therefore, the specification of this application does not describe their constitutions in detail. The central main portion 14 in the automatic document conveying device 4 is equipped with a movable main portion frame member 70. The main portion frame member 70 is mounted on the upper surface of the housing 6 of the electrostatic copying machine 2 via a pair of hinge mechanisms 72 (Fig. 2) disposed at the rear side of the transparent plate 8, and can be manually opened or closed between a closed position shown in Figs. 1 and 3 and an open position shown in Fig. 2. When the main portion frame member 70 is brought to the closed position, the transparent plate 8 is covered with the main portion frame member 70. On the other hand, when the main portion frame member 70 is brought to the open position, the transparent plate 8 is exposed to the view. A portion of the main portion frame member 70 that covers the transparent plate 8 at the closed position assumes the box-like shape with its lower surface open. As clearly shown in Fig. 3, document conveying means 74 that conveys the document onto the transparent plate 8 is disposed in the box-like portion of the main portion frame member 70. The document conveying means 74 is constituted by a conveyor belt mechanism that includes a driven roller 76, a follower roller 78, pushing rollers 80, 82, 84 and 86 disposed maintaining a distance in a direction in which the document is conveyed (right-and-left direction in Fig. 3), and an endless belt 88 wound around these rollers. The frame member 70 is equipped with a main portion drive source 89 (Fig. 3) which may be a reversible electric motor. The main portion drive source 89 selectively drives the document conveying means 74 either in the normally conveying direction indicated by arrow 90 or in the reversely conveying direction indicated by arrow 92. The upper surface of the box-like portion of the main portion frame member 70 constitutes a first document receiving tray 94 that receives the document discharged through the document delivery and re-introduction portion 16. The document delivery and re-introduction portion 16 does not constitute any novel feature of the present invention and may, hence, be those of the forms disclosed in detail in the specification and drawings of US Patent Application Serial No. 07/550853 filed on July 10, 1990 or European Patent Application No. 90113174.8 filed on July 10, 1990 corresponding to Japanese Patent Application No. 175523/1989 (filed July 10, 1989 entitled Automatic Document Conveying Device) filed by the present applicant. Therefore, they are not described in detail in the specification of the present application. The above-mentioned automatic document conveying device 4 conveys the document in any one of a simple mode, a reversing mode or a double reversing mode. Details of the document conveying system in the simple mode, reversing mode and double reversing mode have been clearly described in the specification and drawings of US Patent Application Serial No. 07/557703 filed on July 25, 1990 or European Patent Application No. 90114376.8 filed on July 26, 1990 corresponding to Japanese Patent Application No. 192544/1989 (filed July 27, 1989, entitled Automatic Document Conveying Device) filed by the present applicant. Therefore, its detailed description is not repeated in this specification (i.e. reference should be made to the specification and drawings of the above application for its details). In the above-mentioned diagramed automatic document conveying device 4 attention should be given to the following points. That is, in the diagramed automatic document conveying device 4, the central main portion 14 that includes the movable main portion frame member 70 and the document conveying means (conveyor belt mechanism) 74 mounted thereon, is constituted quite separately from the document introduction portion 12 and the document delivery and re-introduction portion 16. No mutual action of driving force or no mutual action of pressing force exists between the main portion 14 and the document introduction portion 12 or between the main portion 14 and the document delivery and re-introduction portion 16. The introduction portion drive source 69, main portion drive source 89 and delivery portion drive source 165 are arranged in the document introduction portion 12, main portion 14 and document delivery portion 16, respectively, and there does not quite exist any drive coupling relationship between the main portion 14 and the document introduction portion 12 or between the main portion 14 and the document delivery portion 16. Furthermore, the pair of rollers that press each other and that word in cooperation together are not so disposed that one of them exists on the main portion 14 and the other one exists on the document introduction portion 12 or the document delivery and re-introduction portion 16. Therefore, no mutually pressing relationship exists at all between the main portion 14 and the document introduction portion 12 or between the main portion 14 and the document delivery and re-introduction portion 16. Thus, even when open and close operation of the movable main portion frame member 70 is carried out repetitively, the movable main portion frame member 70 of the main portion 14 and the document conveying means (conveyor belt mechanism) 74 are not adversely affected by the driving force or the pressing force and are stably placed at the required position with respect to the transparent plate 8 maintaining sufficiently high precision. Central Main Portion Next, detailed description will be given in respect to the central main portion 14. As described already with reference to Figs. 1 to 3, the central main portion 14 includes the movable main portion frame member 70 and the document conveyor means (conveyor belt mechanism) 74 mounted on the main portion frame member 70. The main portion frame member 70 is mounted on the upper surface of the housing 6 of the electrostatic copying machine 2 by a pair of hinge mechanisms 72 disposed maintaining a distance in the conveying direction so as to pivot between the closed position shown in Figs. 1 and 3 and the open position shown in Fig. 2. If further described with reference to Figs. 4 and 5, the movable main portion frame member 70 mounted on the upper surface of the housing 6 via the pair of hinge mechanisms 72 includes a support base member 216 and a cover member 218 (Figs. 1 to 3, and 9) mounted on the support base member 216. The support base member 216 has a pair of coupling members 220 and a pair of support plates 222 secured to the coupling members 220, respectively. If further described with reference to Figs. 4 to 6, the document conveying means 74 constituted by the conveyor belt mechanism is mounted on the support base member 216 of the main portion frame member 70 in the central main portion 14. The document conveying means 74 includes frontside support means 292 and rear-side support means 294. The front-side support means 292 has a driven-side support member 296 and a follower side support member 298 and, similarly, the rear-side support means 294 has a driven-side support member 300 and a follower-side support member 302. The driven-side support member 296 of the front-side support means 292 is constituted by a slender plate member that extends in the conveying direction (up-and-down direction in Fig. 6). Threaded holes 304 are formed in the front ends at the upper end portions of both side walls of the pair of support members 222 in the support base member 216, and four mounting holes 306 are formed in the driven-side support member 296 to correspond thereto. Set-screws 308 are screwed into the threaded holes 304 through the mounting holes 306, whereby the driven-side support member 296 is secured to the front end of the support plate 222. The follower-side support member 298 of the front-side support means 292 is constituted by a plate member that extends in the conveying direction. The follower-side support member 298 is mounted on the driven-side support member 296 to move over a required range in the conveying direction. Referring, further, to Figs. 4, 5, 7-A and 7-B, a forwardly protruded guide pin 310 and a lock pin 312 are studded on the driven-side support member 296 at the follower-side end (left lower end in Fig. 5). On the other hand, a guide slot 314 and a lock slot 316 are formed in the follower-side support member 298. The guide slot 314 extends in the conveying direction. The lock slot 316 has a relative movement-permitting portion 318 that extends in the conveying direction and a lock portion 320 that extends nearly perpendicularly to the conveying direction. The guide pin 310 is inserted in the guide slot 314 and the lock pin 312 is inserted in the lock slot 316, so that the follower-side support member 298 is mounted on the driven-side support member 296. The driven-side support member 298 has an engaging piece 319 that forwardly protrudes from the upper edge thereof and a grip piece 321 that extends forward from the lower edge thereof. As clearly shown in Figs. 7-A and 7-B, resiliently urging means 322 constituted by a pulling spring is provided between the guide pin 310 of the driven-side support member 296 and the engaging piece 319 of the follower-side support member 298. When the lock pin 312 is positioned in the relative movement-permitting portion 318 of the lock slot 316 as shown in Fig. 7-A, the guide pin 310 moves in the conveying direction in the guide slot 314, so that the lock pin 312 moves in the conveying direction in the relative movement-permitting portion 318 of the lock slot 316, and the driven-side supporting member 298 is allowed to move in the conveying direction with respect to the driven-side support member 296. Resiliently urging means 322 resiliently urges the driven-side support member 298 leftwardly in Fig. 7-A, i.e. toward the direction to extend the full length of the front-side support means 292 defined by the driven-side support member 296 and the driven-side support member 298 in the conveying direction. As will be described later in further detail, a driven roller 76 and a follower roller 78 are mounted between the front-side support means 292 and the rear-side support means 294 maintaining a distance in the conveying direction, and an endless belt 88 is wound round the driven roller 76 and the follower roller 78. The endless belt 88 is maintained under the stretched condition due to the resiliently urging action by the resiliently urging means 322 (under this condition, the full length between the driven-side support member 296 and the follower-side support member 298 is not the possible greatest length but is slightly shorter than it). The grip piece 321 formed in the follower-side support member 298 is gripped or is touched by a finger, and the follower-side support member 298 is moved by a predetermined length rightwards in Figs. 7-A and 7-B, i.e. toward the direction to shorten the full length of the front-side support means 292 defined by the driven-side support member 296 and the follower-side support member 298 against the resiliently urging action of the resiliently urging means 322. Then, the right end portion of the follower-side support member 298 is slightly moved downwardly in Figs. 7-A and 7-B, so that the lock pin 312 is positioned in the lock portion 320 of lock slot 316 as shown in Fig. 7-B. Due to the action of the resiliently urging means 322, therefore, the follower-side support member 298 is prevented from returning to the left in Fig.7-B; i.e. the follower-side support member 298 is locked under the full-length contracted condition as shown in Fig. 7-B (thus, the lock pin 312 and the lock slot 316 work in cooperation to constitute locking means). In Figs. 7-A and 7-B, if the right end portion of the follower-side support member 296 is moved slightly upwards such that the lock pin 312 is positioned in the relative movement-permitting portion 318 of lock slot 316, the locking action is released and the follower-side support member 298 is returned to the condition shown in Fig. 7-A due to the action of the resiliently urging means 322. A driven-side support member 300 of the rear-side support means 294 is also constituted by a plate-like member that extends in the conveying direction. Here, the height of the driven-side support member 300 of the rear-side support means 294 in the up-and-down direction is considerably greater than the height in the up-and-down direction of the driven-side support member 296 of the front-side support means 292. Threaded holes (not shown) are formed in the upper rear ends of both side walls of the pair of support plates 222 in the support base member 216, and four mounting holes 324 are formed in the driven-side support member 300 to correspond thereto. Set-screws (not shown) are screwed into the threaded holes through the mounting holes 324, and the driven-side support member 300 is secured to the rear ends of the support plates 222. The driven-side support member 302 of the rear-side support means 294, too, is constituted by a plate-like member that extends in the conveying direction, and its height in the up-and-down direction is considerably greater than the height in the up-and-down direction of the follower-side support member 298 of the front-side support means 292. The follower-side support member 302 is mounted on the driven-side support member 300 to move over a required range in the conveying direction. If described with reference to Figs. 4 and 5, and Figs. 8-A and 8-B, a rearwardly protruding guide pin 325 and a lock pin 326 are studded on the driven-side support member 300 at the follower-side ends (left lower end portions in Fig. 5). An expanded head is formed at the protruded end of the guide pin 325. On the other hand, a guide slot 328 and a lock slot 330 are formed in the follower-side support member 302. The guide slot 328 extends in the conveying direction and the end of its driven side is open. The lock slot 330 has a relative movement-permitting portion 332 extending in the conveying direction and a lock portion 334 extending nearly perpendicularly to the conveying direction. The guide pin 325 is inserted in the guide slot 328 and the lock pin 326 is inserted in the lock slot 330, so that the follower-side support member 302 is inserted in the driven-side support member 300. The driven-side support member 300 has an engaging piece 336 that forwardly protrudes from the lower edge thereof, and the follower-side support member 302 has an engaging piece 338 that forwardly protrudes from the lower edge thereof. The follower-side support member 302 further has a grip piece 340 (Figs. 5 and 6) that rearwardly extends from the lower edge thereof. As clearly shown in Figs. 8-A and 8-B, resiliently urging means 342 constituted by a pulling spring is disposed between the engaging piece 336 of driven-side support member 300 and the engaging piece 338 of follower-side support member 302. When the lock pin 326 is positioned in the relative movement-permitting portion 332 in the lock slot 330 as shown in Fig. 8-A, the guide pin 325 is allowed to move in the guide slot 326 in the conveying direction and the lock pin 326 moves within the relative movement-permitting portion 332 in the lock slot 330 in the conveying direction, so that the follower-side support member 302 is allowed to move in the conveying direction relative to the driven-side support member 300. The resiliently urging means 342 resiliently urges the follower-side support member 302 toward the left in Fig. 8-A, i.e. toward the direction to extend in the conveying direction the full length of the rear-side support means 294 that is defined by the driven-side support member 300 and the follower-side support member 302. Like the case mentioned in connection with the front-side support means 292, the endless belt 88 (Figs. 2 and 3) is maintained under the stretched condition by the resiliently urging action of the resiliently urging means 342 (under this condition, the full length between the driven-side support member 300 and the follow-side support member 302 is not the possible greatest length but is slightly shorter than it). The grip piece 340 of the follower-side support member 302 is gripped or is touched by finger, and the follower-side support member 302 is moved by a predetermined length toward the right in Figs. 8-A and 8-B, i.e. toward the direction to shorten the full length of the rear-side support means 294 defined by the driven-side support member 300 and the follower-side support member 302 against the resiliently urging action of the resiliently urging means 342. Then, the right end portion of the follower-side support member 302 is slightly moved downwards in Figs. 8-A and 8-B, so that as shown in Fig. 8-B, the lock pin 326 is positioned in the lock portion 334 of lock slot 330. The follower-side support member 302 is then prevented, by the action of the resiliently urging means 342, from returning to the left in Fig. 8-B, and is locked under the full-length contracted condition that is shown in Fig. 8-B (thus, the lock pin 326 and the lock slot 330 work in cooperation to constitute locking means). If the right end portion of the follower-side support member 302 is slightly moved upwards in Figs. 8-A and 8-B so that the lock pin 326 is positioned in the relative movement-permitting portion 332 of lock slot 330, the locking action is released and the follower-side support member 302 is returned back to the condition shown in Fig. 8-A owing to the action of the resiliently urging means 342. If described with reference to Figs. 4 to 6, a shaft member 348 is rotatably fitted via bearing sleeves 344 and 346 between one end (upper end portion of Fig. 6) of the driven-side support member 296 of the front-side support means 292 and one end (upper end portion in Fig. 6) of the driven-side support member 300 of the rear-side support means 294, and a driven roller 76 that continuously extends in the direction of width (right-and-left direction in Fig. 6) is secured to the shaft member 348. Furthermore, a shaft member 354 is rotatably fitted via bearing sleeves 350 and 352 between one end (lower end portion in Fig. 6) of the follower-side support member 298 of the front-side support member 292 and one end (lower end portion in Fig. 6) of the follower-side support member 302 of the rear-side support means 294, and a plurality of follower rollers 78 are fastened to the shaft member 354 maintaining a suitable distance in the axial direction thereof. As clearly shown in Fig. 3, an endless belt 88 is wound round the driven roller 76 and the follower roller 78. In the diagramed embodiment constituted according to the present invention, the driven-side support member 296 and the follower-side support member 298 constituting the front-side support means 292 have a size in the up-and-down direction which is smaller than the diameters of the driven roller 76 and of the follower roller 78, and the upper running portion and the lower running portion of the endless belt 88 wound round the driven roller 76 and the follower roller 78 are positioned over and under the driven-side support member 296 and the follower-side support member 298, respectively. In view of the above fact, a belt locking member 355 (Figs. 5 and 6) is mounted on one end (upper end portion in Fig. 6) of the driven-side support member 296 of the front-side support means 292. The belt locking member 355 that may be made of a suitable synthetic resin has an inside shape that corresponds to the outer at one end of the driven-side support member 296, and is detachably and resiliently engaged with one end of the driven-side support member 296. On the inside of the belt locking member 355 is formed a locking flange 357 that is positioned opposed to one side edge of the endless belt 88 and that prevents the endless belt 88 from moving forward. Further, on the outside of the belt locking member 355 is formed a grip piece 359 that can be gripped by hand at the time when the belt locking member 355 is to be mounted on, or removed from, the driven-side support member 296. Attention should be given to the following fact concerning the aforementioned document conveying means (conveyer belt mechanism). As will be described later, a cover member 218 is mounted on the support base member 216 and on the conveyer belt mechanism that is mounted thereon; i.e. the conveyer belt mechanism is covered with the cover member 218. The endless belt 88 in the conveyer belt mechanism will be fouled or damaged after used for extended period of time. In such a case, the endless belt 88 must be renewed, and the following operation may be carried out to replace the endless belt 88. First, the cover member 218 is removed. Then, the belt locking member 355 is removed from one end portion of the driven-side support member 296 of the front-side support means 292. Thereafter, the follower-side support member 298 in the front-side support means 292 is operated as mentioned above, and the driven-side support member 296 and the follower-side support member 298 in the front-side support means 292 are locked under the full-length contracted condition as shown in Fig. 7-B. At the same time or thereafter, the follower-side support member 302 in the rear-side support means 294 is operated as described above, and the driven-side support member 300 and the follower-side support member 302 in the rear-side support means 294 are locked under the full-length contracted condition as shown in Fig. 8-B. At a result, the driven roller 76 and the follower roller 78 are brought close to each other, and the endless belt 88 is shifted to be placed under the slackened condition from the stretched condition. It is therefore allowed to very easily pull out the endless belt 88 forward to remove it. The driven-side support member 296 and the follower-side support member 298 of the front-side support means 292 have a size in the up-and-down direction which is so small as will not interrupt the endless belt 88 from being pulled out forward. Then, a new endless belt 88 is moved from the front toward the rear, and is wound round the driven roller 76, follower roller 78, and pressing rollers 80, 82, 84 and 86 to load it. At this moment, the driven roller 76 and the follower roller 78 are maintained under the condition where they are brought close to each other, and it is allowed to very easily load the new endless belt 88 as required. Then, through the aforementioned operation for the rear-side support means 294, locking under the full-length contracted condition is released, and the driven-side support member 300 and the follower-side support member 302 in the rear-side support means 294 are placed under the condition (shown in Fig. 8-A) where they are resiliently urged toward extending the full length thereof due to the action of the resiliently urging means 342. Also in the front-side support means 292, locking under the full-length contracted condition is released due to the above-mentioned operation, and the driven-side support member 296 and the follower-side support member 298 in the front-side support means 292 are placed under the condition (shown in Fig. 7-A) where they are resiliently urged toward extending the full length thereof due to the action of the resiliently urging means 322. Then, the newly mounted endless belt 88 is stretched by the resiliently urging action of the resiliently urging means 322 and 342. Thereafter, the belt locking member 355 is mounted again to one end of the driven-side support member 296 in the front-side support member 292. Then, the cover member 218 is mounted as required. The above-mentioned operation for replacing the endless belt 88 can be very easily carried out by one person. If described with reference to Figs. 4, 5 and 9, the movable main portion frame member 70 of the central main portion 14 includes, as described already the cover member 218 that covers the document conveying means (conveyer belt mechanism) 74. As mentioned above, protruded pieces 229 are formed at the rear end of one side wall 226 of the pair of coupling members 220 in the support base member 216 of the movable main portion frame member 70, and a threaded hole 231 is formed in the protruded pieces 229. A pair of slots or holes (not diagramed) are formed in the rear wall of the cover member 218 to correspond to the threaded holes 231. Set-screws (not shown) are screwed into the threaded holes 231 of the protruded pieces 229 through the slots or holes formed in the rear wall of the cover member 218, and the rear wall of the cover member 218 is secured to the coupling members 220 of the support base member 216. As shown in Figs. 4 and 5, furthermore, the driven-side support member 296 of the front-side support means 292 in the document conveying means 74 has support protrusions 402 and 404 that protrude forward from the upper edge of the support member 296. A hole 406 is formed in one end portion (right upper end in Fig. 4) of the support protrusion 402, and a hole 408 is formed in the support protrusion 404. Further, a pair of coupling blocks (not shown) are fastened to the inner surface of the upper wall of cover member 218 to correspond to the holes 406 and 408, and a threaded hole is formed in each of the coupling blocks. Set-screws (not shown) are screwed into the threaded holes in the coupling blocks through the holes 406 and 408, and the front portion of upper wall of the cover member 218 is fastened to the driven-side support member 296 and is, hence, fastened to the support base member 216 via the driven-side support member 296. If further described with reference to Figs. 1 and 9, the cover member 218 has a high bulging portion 410 located at the rear end portion thereof and a low box-like portion 412 that extends forward from the bulging portion 410. The high bulging portion 410 is relatively high and the low box-like portion 412 is relatively low. The upper surface of the low box-like portion 412 that covers the document conveying means (conveyer belt mechanism) 74 constitutes the document receiving tray 94. An upright wall 414 is formed at one edge (right upper side edge in Fig. 9) of the low box-like portion 412. As will be understood with reference to Fig. 1, the upright wall 414 upwardly extends to slightly under the first discharge opening 114 in the document delivery and re-introduction portion 16. Recessed portions 416, 418 and 420 are formed in the rear portion, the other edge portion (left lower side edge in Fig. 4) and the front portion on the upper surface of the low box-like portion 412 (in other words, the upper surface of the low box-like portion 412 is bulged in the areas other than recessed portions 416, 418 and 420, and the amount of the bulging gradually increases toward the direction indicated by the arrow 422).

Claims: An automatic document conveying device to be applied to an image processor that has a transparent plate (8) disposed on the upper surface of a housing (6) so that a document to be processed is placed thereon, comprising a main portion (14) that includes a movable main portion frame member (70) mounted to pivot between a closed position to cover said transparent plate (8) and an open position to expose said transparent plate (8) into view, and a document conveying means (74) mounted on said main portion frame member (70) to convey the document along said transparent plate (8) when said main portion frame member (70) is located at said closed position; wherein said document conveying means (74) is constituted by a conveyer belt mechanism that includes a front-side support means (292) and a rear-side support means (294) disposed in the direction of width maintaining a distance, a driven roller (76) and a follower roller (78) provided between said front-side support means and said rear-side support means maintaining a distance in the direction of delivering document, and an endless belt (88) wound round said driven roller (76) and said follower roller (78); characterized in that said front-side support means (292) in said conveyer belt mechanism is constituted by a driven-side support member (296) and a follower-side support member (298) that are so combined together as to change the full length thereof as they move relative to each other in the conveying direction, a resiliently urging means (322) that resiliently urges said driven-side support member (296) and said follower-side support member (298) toward a direction to increase the full length thereof and a locking means (312, 316) which releasably locks said driven-side support member (296) and said follower-side support member (298) under the condition in which they are moved relative to each other by a predetermined amount in a direction to shorten the full length thereof against the resiliently urging action of said resiliently urging means (322), wherein the front end of said driven roller (76) is mounted on said driven-side support member (296), the front end of said follower roller (78) is mounted on said follower-side support member (298), said endless belt (88) is placed under the stretched condition when said driven-side support member (296) and said follower-side support member (298) are resiliently urged by said resiliently urging means (322) in a direction to extend the full length thereof, and said endless belt (88) is placed under the slackened condition when said driven-side support member (296) and said follower-side support member (298) are put under the condition where the full length thereof is shortened. The automatic document conveying device according to claim 1, wherein said rear-side support means (294) in said conveyer belt mechanism is constituted by a driven-side support member (300) and a follower-side support member (302) that are so combined together as to change the full length thereof as they move relative to each other in the conveying direction, a resiliently urging means (342) that resiliently urges said driven-side support member (300) and said follower-side support member (302) toward a direction to increase the full length thereof, and a locking means (326, 330) which releasably locks said driven-side support member (300) and said follower-side support member (302) under the condition in which they are moved relative to each other by a predetermined amount in a direction to shorten the full length thereof against the resiliently urging action of said resiliently urging means (342), wherein the front end of said driven roller (78) is mounted on said driven-side support member (300), the front end of said follower roller (78) is mounted on said follower-side support member (302), said endless belt (88) is placed under the stretched condition when said driven-side support member (300) and said follower-side support member (302) are resiliently urged by said resiliently urging means (342) in a direction to extend the full length thereof, and said endless belt (88) is placed under the slackened condition when said driven-side support member (300) and said follower-side support member (302) are put under the condition where the full length thereof is shortened. The automatic document conveying device according to claim 1, wherein a slot (316) is formed in one of said driven-side support member (296) or said follower-side support member (298), said slot (316) having a relative movement-permitting portion (318) that extends in the conveying direction and a lock portion (320) that extends nearly perpendicularly to the conveying direction, a pin (312) is disposed on the other one of said driven-side support member (296) or said follower-side support member (298) so as to be inserted in said slot (316), said driven-side support member (296) and said follower-side support member (298) are allowed to move relative to each other in the conveying direction as said pin (312) moves in said relative movement-permitting portion (318) of said slot (316), and when said pin (312) is positioned at the lock portion (320) of said slot (316), said driven-side support member (296) and said follower-side support member (298) are placed under the condition where the full length thereof is shortened, and the relative movement of these two members (296, 298) is locked in the conveying direction. The automatic document conveying device according to claim 1, wherein said main portion frame member (70) is constituted by a support base member (216) that is movably mounted and a cover member (218) that is removably mounted on said support base member (216), said conveyer belt mechanism is mounted on said support base member (216), and when said cover member (218) is mounted on said support base member (216), said conveyer belt mechanism is covered by said cover member (218) and when said cover member (218) is removed from said support base member (216), said conveyer belt mechanism is exposed to view, enabling the endless belt (88) in said conveyer belt mechanism to be easily replaced. The automatic document conveying device according to claim 4, wherein said driven-side support member (296, 300) is mounted on said support base member (216), and said follower-side support member (298, 302) is mounted on said driven-side support member (296, 300). The automatic document conveying device according to claim 5, wherein a belt locking member (355) that prevents said conveyer belt (88) from moving forward is detachably mounted on said driven-side support member (296) in said front-side support means (292), and it is allowed to pull said endless belt (88) forward from said driven roller (76) and from said follower roller (78) when said belt locking member (355) is removed from said driven-side support member (296) and when said driven-side support member (296) and said follower-side support member (298) are put under the condition where the full length thereof is shortened.

Inventors: IRIE YOICHIRO, KIDA YASUHIKO, NAGAO TSUYOSHI TAIHOMIDORIBASH, TAKEDA YOSHIYUKI, IRIE, YOICHIRO, KIDA, YASUHIKO, NAGAO, TSUYOSHI, TAIHOMIDORIBASHI, TAKEDA, YOSHIYUKI
Applicants: MITA INDUSTRIAL CO LTD, MITA INDUSTRIAL CO., LTD.
Application year: 1990
Main classification: G03G15
IPC codes: G03G15, G03B27, B65H5