Image-forming machine

Abstract: An image-forming machine comprising a conveying passage (51) for conveying a sheet material through a transfer zone, a first (66) and a second (68) feed means for feeding the sheet material to the conveying passage (51), a first feed passage (86) for conducting the sheet material delivered from the first feed means (66) to the conveying passage (51), a second feed passage (96) for conducting the sheet material delivered from the second feed means (68) to the conveying passage (51), and a first (124) and a second (126) opening-closing member for opening and closing the first and second feed passages. Various improvements are made on the first (124) and second (126) opening-closing members. Further provided are an improvement for suppressing noises, an improvement for preventing folding of a sheet material, an improvement for easily switching over to a mode of forming an image on both surfaces of a sheet material, an improvement for accurately conducting the sheet material from a reversal holding portion (382) to a return passage (384), and an improvement for positioning the sheet material received in the receiving-refeeding means (386) at a predetermined widthwise position in the above and other types of image-forming machines.

Description: Field of the Invention This invention relates to an image-forming machine such as an electrostatic copying machine or a laser beam printer. Description of the Prior Art Image-forming machines such as an electrostatic copying machine have been in widespread commercial use. Examples thereof may be found in e.g. US-A-4 733 310 and JP-A-60 067 968. Conventional image-forming machines, however, have various problems yet to be solved, for example those listed below. (a) A feed passage for conducting a sheet material delivered from feed means to a conveying passage cannot be sufficiently opened. (b) When the feed passage is defined by an opening-closing member which is freely openable or closable, it is difficult to ascertain easily and accurately whether the opening-closing member is held at a closing position. (c) The structure of the machine is complex in relation to locking means for locking the opening-closing member into the closing position. (d) The sheet material delivered toward the feed passage from the feed means produces noises. (e) When delivered from the feed means, the sheet material folds at both ends of its leading end portion. (f) The structure of the machine is complex in relation to the opening-closing member. (g) The opening-closing member is difficult to hold accurately at the closing position. Summary of the Invention It is a first object of this invention to provide an excellent image-forming machine in which a feed passage for feeding a sheet material to a conveying passage can be sufficiently opened. A second object of the invention is to provide an excellent image-forming machine in which whether an opening-closing member defining a feed passage is held at a closing position can be ascertained easily and accurately. A third object of this invention is to provide an excellent image-forming machine in which locking means for locking an opening-closing member into a closing position can be held accurately in a locked state by a relatively simple structure. A fourth object of this invention is to provide an excellent image-forming machine in which noises produced at the time of delivering a sheet material can be suppressed. A fifth object of this invention is to provide an excellent image-forming machine in which folding of a sheet material which is liable to occur when it is delivered from feed means can be prevented. A sixth object of this invention is to provide an excellent image-forming machine in which the structure relating to an opening-closing member is simple. A seventh object of this invention is to provide an excellent image-forming machine in which an opening-closing member can be accurately held at a closing position. Other objects and features of this invention will become apparent from the following description. Brief Description of the Drawings Figure 1 is a sectional view showing in a simplified manner one embodiment of a laser beam printer which is one example of the image-forming machine in accordance with this invention; Figure 2 is a partial sectional view showing a first opening-closing member and a second opening-closing member and elements relating to them in the laser beam printer of Figure 1; Figure 3 is a perspective view showing the first opening-closing member of Figure 2; Figure 4 is a perspective view showing the second opening-closing member of Figure 2; Figure 5 is a top plan view showing part of a first feed means and its vicinity in the laser beam printer of Figure 1; Figure 6 is a view for illustrating the state of a sheet material delivered from a first feed means; Figure 7 is a view for illustrating the operation of opening a first feed passage in the laser beam printer shown in Figure 1; Figure 8 is a view showing the state in which the first feed passage and a second feed passage in the laser beam printer of Figure 1 are opened; Figure 9 is a top plan view showing the state in which the first opening-closing member and the second opening-closing member in the laser beam printer shown in Figure 1 are each held at a closing position; Figure 10 is a view showing the state in which the first opening-closing member is pivoted toward the closing position when the second opening-closing member is not at the closing position; Figure 11 is a top plan view corresponding to Figure 10; Figure 12 is a view showing in a simplified manner a first modified embodiment of the manner of mounting the first opening-closing member; Figure 13 is a view showing in a simplified manner a second modified example of the manner of mounting the first opening-closing member; Detailed Description of Preferred Embodiments The invention will be described in detail with reference to the accompanying drawings. Outline of the laser beam printer as a whole With reference to Figure 1, the outline of one embodiment of a laser beam printer as one example of the image-forming machine in accordance with this invention will be described. In Figure 1, the illustrated laser beam printer includes a nearly rectangular paralellpipedal main body 2 which has a so-called shell-type, i.e. vertically divisible, structure comprised of a lower frame member 4 and an upper frame member 6 mounted on the lower frame member 4 through a shaft member 5 (constituting a central axis extending perpendicularly to the sheet surface in Figure 1) so that it is free to pivot between an opening position (not shown) and a closing potition (the position shown in Figure 1). A process unit shown by reference numeral 8 is disposed in the upper frame member 6 of the main body 2. The illustrated process unit 8 is provided with a unit frame 10 detachably mounted on the upper frame member 6, and a rotating drum 12 is rotatably mounted on the unit frame 10. An electrostatographic material is disposed on the peripheral surface of the rotating drum 12. Around the rotating drum 12 which is to be rotated in the direction shown by an arrow 14 are disposed a charging corona discharger 16, a developing device 18, a transfer corona discharger 20 and a cleaning device 22. An optical unit shown by numeral 34 is disposed in the upper space of the upper frame member 6, i.e. the space above the process unit 8. The optical unit 34 includes a box-like unit housing 36. Within the unit housing 36 are disposed a laser light source (not shown), a rotating polygon mirror 38, a first reflecting mirror 40, a second reflecting mirror 42 and a lens 44. The laser light source (not shown) irradiates laser light based on an image information outputted from a computer, for example, onto the rotating polygon mirror 38. The laser light reflected from the rotating polygon mirror 38 is reflected by the first reflecting mirror 40 and the second reflecting mirror 42, passes through the lens 44 and is projected onto the surface of the rotating drum 12 in a projecting zone 46, as shown by a one-dot chain line in Figure 1. In the lower portion of the main body 2, namely in the lower frame member 4, is disposed a conveying means 50 for conveying a sheet material which may be plain paper through a transfer zone 48 existing between the rotating drum 12 and the transfer corona discharger 20. The illustrated conveying means 50 is provided with a conveying roller pair 52, a guide member 54, a guide member 56 and a fixing roller pair 58, and defines a conveying passage 51 extrending nearly in a straight line from the nipping site 60 of the conveying roller pair 52 to the nipping site 62 of the fixing roller pair 58. In the illustrated embodiment, a hand-insertion feed means 64 is provided at the right end of the conveying passage 51, and below the conveying means 50, namely in the lower portion of the lower frame member 4, a first feed means 66 and a second feed means 68 are disposed. The first feed means 66 is comprised of a receiving portion 78 defined by the bottom portion of the main body 2, i.e. the bottom portion of the lower frame member 4, a cassette 82 detachably loaded into the receiving section 78 through an opening 80 formed in the left surface of the main body 2, and feed means 84 disposed above the receiving portion 78. Sheet materials are loaded into the cassette 82. When the feed means 84 is rotated in the direction shown by an arrow the uppermost sheet material in the cassette 82 is delivered from the cassette 82 and fed into the conveying passage through a first feed passage 86. The second supply means 68 positioned above the first supply means 66 is comprised of a receiving portion 88 defined in the upper portion of the lower frame member 4, a cassette 92 loaded detachably into the receiving portion 88 through an opening 90 formed in the left surface of the main body 2, and feed means 94 disposed above the receiving portion 88, and sheet materials are loaded into the cassette 92. When the feed means 94 is rotated in the direction of arrow, the uppermost sheet material is delivered from the cassette 92, and fed to the conveying passage through the second feed passage 96. A receiving plate 98 constituting a first receiving means is disposed in the left end portion in Figure 1 of the main body 2. The illustrated receiving plate 98 is comprised of a first piate 100 having a slightly concave upper surface (the upper surface in the state shown by a two-dot chain line in Figure 1) and a second plate 102 extending nearly in a straight line. A first discharge passage 106 is provided between the receiving plate 98 and the conveying passage 51. The illustrated first discharge passage 106 is defined by a guide member 108 and a first discharge roller pair 110. In the illustrated embodiment, there is also provided a second receiving means in the upper end of the main body 2. The second receiving means is defined by an inclined upper surface 112a in the upper wall 112 of the main body 2. In the upper end portion of the inclined upper surface 112a is mounted an auxiliary receiving member 114 which is free to pivot between a receiving position extending following the inclined upper surface 112a and a storage position above the inclined upper surface 112a. A second discharge passage 116 is provided between the second receiving member and the first discharge passage 106. The second discharge passage 116 is defined by the receiving plate 98 at the storage position (particularly, the right surface in Figure 1 of the second plate 102 in the storage state), a plurality of guide ribs 120 (one of which is shown in Figure 1) provided on the inner surface of the wall 118 and a second discharge roller pair 122. The operation of the laser beam printer described above will be described below in a general manner. While the rotating drum 12 is rotated in the direction of arrow 14, the charging corona discharger 16 charges the electrostatographic material of the rotating drum 12 to a specific polarity. Then, in the projecting zone 46, laser light from the laser light source (not shown) in the optical unit 34 is projected onto the electrostatographic material. As a result, a latent electrostatic image corresponding to the image information is formed on the surface of the electrostatographic material. First feed passage, second feed passage and related elements Now, a detailed description will be given on the first feed passage 66 for conducting the sheet material delivered from the first feed means 66 to the conveying passage, the second feed passage 96 for conducting the sheet material delivered from the second feed means 68 to the conveying passage, and elements related to them. With reference to Figure 2 as well as Figure 1, a greater portion of the first feed passage 86 is defined by a first opening-closing member 124 and a second opening-closing member 126, and a greater portion of the second feed passage 96 is defined by the second opening-closing member 126. The downstream portion of the first feed passage 86 and the downstream portion of the second feed passage 96 are associated, and the associated portion of the two passages is connected to the upstream end of the conveying passage 51. With reference to Figure 3, the illustrated first opening-closing member 124 has a pair of end walls 128 and 130 spaced from each other a predetermined distance, and between these end walls 128 and 130 are provided an outside wall 132, an inside wall 134, a bottom wall 136 and an upper wall 138 (see Figure 1 also). In the illustrated embodiment, the inside wall 134 has a substantially flat lower portion 140 and an upper portion 142 extending upwardly in an arcuate curved shape, and as can be seen from Figures 1 and 2, the inside surface of the upper portion 142 of the inside wall 134 defines one side of the first feed passage 86, i.e. its right side in Figure 1. As shown clearly in Figures 1 and 5, a plurality of guide ribs 144 in spaced-apart relationship in the widthwise direction (the direction perpendicular to the sheet surface in Figure 1, the vertical direction in Figure 5) are provided integrally on the inside surface (the surface acting as a guiding surface) of the upper portion 142 of the inside wall 134 (in Figure 3, the guide ribs 144 are omitted). Contact-preventing depressed portions 146 are defined in both end portions in the widthwise direction of the upper portion 142 of the inside wall 134. In the illustrated embodiment, the central part in the widthwise direction of the upper portion 142 of the inside wall 134 extends downwardly with a relatively large curving from the nearly central part in the vertical direction. On the other hand, both end portions in the widthwise direction of the upper portion 142 of the inside wall 134 extend downwardly with a relatively small curving from its nearly central part in the vertical direction. By the differences in curvature between these curved surfaces, the contact-preventing depressed portions 146 are provided in both ends of the upper portion 142. In the illustrated embodiment, an introduction protrusion 148 protruding into the receiving portion 78 of the first supply means 66 are provided integrally, and nearly horizontally in Figures 1 and 2, in the upstream end of the central part, in the widthwise direction, of the upper portion 142. The introduction protrusion 148 is provided over substantially the entire width of the part between the contact-preventing depressed portions 146 in the upper portion 142 of the inside wall 134, and the guide ribs 144 provided on the upper portion 142 of the inside wall 134 extend to the introduction protrusion 148. Supporting portions 150 and 152 are formed integrally in the end walls 128 and 130 of the first opening-closing member 124 by removing them locally in a nearly U shape, and outwardly projecting pins 154 and 156 are provided at the end parts of the supporting portions 150 and 152. On the other hand, the lower frame member 4 has a pair of vertical base plates 158 and 160 (Figure 5) which are disposed in spaced-apart relationship perpendicularly to the sheet surface in Figure 1 and vertically in Figure 5. Supporting plate pieces 162 are provided in the inside surfaces of the vertical base plates 158 and 160 (Figure 2 shows only one supporting plate 162 disposed in the inside surface of the base plate 158), and an elongate hole 164 extending to the right nearly horizontally in Figures 1 and 2 is formed in each supporting plate piece 162 (Figure 2 shows one hole 164 formed in one supporting plate piece 162 and Figure 1 shows the other hole 164 in the supporting plate piece 162 not shown in the drawings). One end portion (the left inside end portion in Figures 1 and 2) extends while curving slightly upwardly. The pins 154 and 156 provided in the first opening-closing member 124 are detachably received in the pair of elongate holes 164. If desired, it is possible to provide pins in the vertical base plates 158 and 160 and elongate holes in the end walls 128 and 130 of the first opening-closing member 124. The first opening-closing member 124 may be formed of a synthetic resin, and by pressing the base parts of the supporting portions 150 and 152, it can be elastically deformed inwardly. This elastic deformation permits detachment of the pair of pins 154 and 156 from the corresponding holes 164. As will be described in detail later on, the first opening-closing member 124 is free to move between an operating position at which the pins 154 and 156 are positioned respectively at the end portions of the holes 164 (the position shown in Figures 1 and 2 and by a two-dot chain line 124 in Figure 7) and a removed position at which the pins 154 and 156 are positioned in the other end portions of the holes 164 (the position in Figure 7 by a solid line and in Figure 8) along these holes 164, and also free to pivot between a closing position at which it defines one side of the first feed passage 86 (the position shown in Figures 1 and 2 and by the two-dot chain line 124 in Figure 7) and an opening position at which it permits opening of the first feed passage 86 (the position shown in Figure 7 by a solid line and in Figure 8). The contact-preventing depressed portion 146 and the introduction protrusion 148 in the first opening-closing member 124 and the first feed means 66 are further constructed as shown below in the illustrated embodiment. In the first feed means 66, the cassette 82 is equipped with a box-like cassette body 166 having an open top, which is adapted to be mounted detachably between the pair of vertical base plates 158 and 160 of the lower frame member 4 through the opening 80. A carrying plate 168 is disposed within the cassette body 166, and a biasing spring (not shown) is interposed between the carrying plate 168 and the bottom wall of the cassette body 166. The rear end portion of the carrying plate 168 is mounted on the cassette body via a pin 170 so that the plate 168 is free to pivot. A stack of sheet materials which may be plain paper are placed on the carrying plate 168. Claw members 172 (Figure 5) for preventing overlapping feed of the sheet materials are disposed at both corners of the front end portion of the cassette body 166. The pair of claw members 172 can slightly move up and down and act on the two corners of the leading end of the sheet materials received in the cassette body. The feed means 84 is provided with a shaft member 174 mounted rotatably between and across the pair of vertical base plates of the lower frame member 4. A pair of feed rollers 176 are mounted on the shaft member 174 in an axially spaced-apart relationship. The first feed means 66 and the contact-preventing depressed portion 146 are arranged in the positional relationship shown in Figure 5. Specifically, the contact-preventing depressed portion 146 is disposed opposite to the claw member 172 and its vicinity in the cassette 82. Generally, as shown in Figure 6, when a sheet material whose leading end is arrested at its corners by the claw members 172 is to be delivered, that part of the sheet material which exists between the feed roller 176 and the claw members 172 bends upwardly, leaves the claw members 172 and jumps forwardly (shown by the two-dot chain line in Figure 6). The sheet material then continues to advance by the action of the feed roller 176. Accordingly, if the contact-preventing depressed portion 146 is not provided, the corners of the leading end of the sheet material (particularly, that part which exists between the feed roller 176 and the claw members 172) will contact the inside wall 134 of the first opening-closing member 124 and is likely to fold downwardly. The provision of the contact-preventing depressed portions 146 in both widthwise end portions of the inside wall 134 serves to accurately prevent the corner portions of the leading end of the sheet material from contacting the inside wall 134 upon delivery from the cassette 82. The side of the contact-preventing depressed portion 146 is such that the leading end of the sheet material does not contact the inside wall 134. A sufficient effect can be obtained, for example, when the height h in Figure 6 is about 15 mm. When as in the illustrated embodiment, the feed means 84 is composed of the pair of feed rollers 176, it is preferable to provide one contact-preventing depressed portion 146 opposite to the part between one feed roller 176 and the claw members 172 and the other contact-preventing depressed portion 146 opposite to the part between the other feed roller 176 and the claw members 172. The first feed means 66 and the introduction protrusion 148 are arranged in the positional relationship shown in Figure 1, 5 and 6. Specifically, the introduction protrusion 148 is constructed such that its end 148 projects to a point above the front wall 178 of the cassette body 166 loaded in the cassette-receiving section 78, and its protruding end surface defines nearly the same plane with the inside surface of the front wall 178 (in relation to this structure, a cut 180 corresponding to the introduction protrusion 148 is formed in the upper end of the front wall 178 of the cassette body 166). Accordingly, the projecting end surface of the introduction protrusion 148, as can be understood from Figure 1, restricts the leading ends of the sheet materials received in the cassette body 166 and the inside surface of the front wall 178 of the cassette body 166. In the prior art, the introduction protrusion 148 for conducting the sheet material delivered from the cassette 82 to the first feed passage 86 is not provided, and in this case, a space exists between the front wall 178 of the cassette body 166 loaded in the cassette-receiving section 78 and the inside wall 134 of the first opening-closing member 124. Hence, when the sheet material delivered from the cassette body 166 is fed to the upwardly curved feed passage and its trailing end passes through the above-mentioned space, the stiffness of the sheet material itself causes its trailing end to touch the upstream end of the inside wall 134, and consequently, produce noises. If, on the other hand, the introduction protrusion 148 is provided as described above, there is substantially no space between the front wall 178 of the cassette body 166 and the inside wall 134 of the opening-closing member 124 at a part where the introduction protrusion 148 exists. The sheet material delivered from the cassette body 166 is therefore guided by the upper surface of the introduction protrusion 148 and conducted to the first feed passage 86, and its trailing end is accurately prevented from contacting the upstream end of the inside wall 134. To conduct the sheet material smoothly to the first feed passage 86, it is preferable to design the introduction protrusion 148 such that the uppermost sheet material in the stack of sheet materials in the cassette body 166 exists on nearly the same level as the upper surface of the introduction protrusion 148. This construction serves to prevent the occurrence of noises effectively. When as in the illustrated embodiment, the feed means 84 consists of the pair of feed rollers 176, that part of the sheet material which exists between the feed rollers 176 is fed stably by the feed rollers 176. It is preferable therefore to provide the introduction protrusion 148 in correspondence to that part of the sheet material which is stably delivered, namely that part which exists between the pair of feed rollers 176. Now, with reference to Figures 1, 2 and 4, the second opening-closing member 126 will be described in detail. The illustrated second opening-closing member 126 has a pair of spaced end walls 182 and 184 which are slightly larger than the pair of end walls 128 and 130 in the first opening-closing member 124, and a lower wall 186 extending downwardly in a straight line and an upper arcuate wall 188 extending while curving upwardly are disposed between the pair of end walls 182 and 184. As can be understood from Figures 1 and 3, in the illustrated embodiment, the outside surfaces (the right surfaces in Figures 1 and 2) of the lower wall 186 and the upper arcuate wall 188 define the left side in Figure 1 of the first feed passage 86, and the inside surface (the left surface in Figures 1 and 2) of the upper arcuate wall 188 defines the right side in Figure 1 of the second feed passage 96. As clearly shown in Figure 1, in the second opening-closing member 126, a plurality of guide ribs 190 are provided in spaced-apart relationship on the outside surfaces of the lower wall 186 and the upper arcuate wall 188 in the widthwise direction (perpendicularly to the sheet surface in Figures 1 and 2), and a plurality of guide ribs 192 are provided at widthwise intervals on the inside surface of the upper arcuate wall 188. Furthermore, a plurality of contacting ribs 194 are provided on the inside surface of the lower wall 186 at widthwise intervals. In Figure 4, the guide ribs 190 and 192 and the contacting ribs 194 are omitted. In the second opening-closing member 126, a contact-preventing depressed portion 196 is defined in both widthwise end portions of the upper arcuate wall 188, and an introduction protrusion 198 slightly projecting into the cassette receiving section 88 of the second supply means 68 in the widthwise central part of the upper arcuate wall 188 which acts as a guiding surface of the second feed passage 96, as in the first opening-closing member 124. In the illustrated embodiment, the widthwise central part of the upper arcuate wall 188 extends downwardly while curving relatively greatly, and the widthwise end portions of the upper arcuate wall 188 extend inclinedly downwardly in a nearly straight line. By these differences in shape, the contact preventing depressed portions 196 are formed in these end portions. The introduction protrusion 198 is provided over substantially the entire width of a part between the contact-preventing depressed portions 196 in the upper arcuate wall 188, and extends nearly horizontally to the left in Figures 1 and 2 towards the cassette receiving section 88. The guide ribs 192 extend to the introduction protrusion 198. Supporting protrusions 200 and 202 projecting to the left in Figures 1 and 2 are integrally provided in the lower end portions of the end walls 182 and 184 of the second opening-closing member 126, and pins 204 and 206 projecting outwardly are provided in the supporting protrusions 200 and 202. On the other hand, a plate 208 defining the under surface of the cassette receiving section 88 is set between the pair of vertical base plates 158 and 160 (Figure 5) of the lower frame member 4. To the undersurface of the plate 208 are secured a pair of supporting brackets (Figure 2 shows a front bracket 210 and Figure 1, a rear bracket 210). The pins 204 and 206 in the second opening-closing member 126 are detachably and pivotally mounted on the pair of supporting brackets 210. The second opening-closing member 126 can also be formed of a synthetic resin. By pressing the base plates of the supporting protrusions 200 and 202, they can be elastically deformed inwardly, and the pins 204 and 206 can be detached from the supporting brackets 210. As will be described in detail later on, the second opening-closing member 126 is free to pivot between a closing position (the position shown in Figures 1 and 2) at which its inside surface defines one side of the second feed passage 96 and its outside surface defines the other surface of the first feed passage 86) and an opening position (the position shown in Figure 8) at which it opens the second feed passage 96. The second feed means 68 is of substantially the same construction as the first feed means 66. The cassette 92 is provided with a box-like cassette body 212 having an open top, and is detachably loaded through the opening 90 into the cassette receiving section defined by the pair of vertical base plate 158 and 160 and the plate 208. Within the cassette body 212 is disposed a carrying plate 214 which is free to pivot vertically with its rear end portion as a fulcrum. A biasing spring (not shown) is interposed between the carrying plate 214 and a bottom wall of the cassette body 212. The feed means 94 is equipped with a shaft member 216 rotatably mounted between, and across, the vertical base plates 158 and 160. A pair of feed rollers 218 (only one of which is shown in Figures 1 and 2) are mounted on the shaft member 216 in axially spaced relationship. The contact-preventing depressed portions 196 and the introduction protrusion 198 in the second feed means 68 and the second opening-closing member 126 are arranged in substantially the same positional relationship as the contact-preventing depressed portions 146 and the introduction protrusion 148 in the first feed means 86 and the first opening-closing member 124, and they operate in substantially the same manner. Accordingly, a detailed description of the structure and operation of these members 196 and 198 is omitted herein. In relation to the first opening-closing member 124, first locking means 220 are provided in order to releasably lock the first opening-closing member 124 into the closing position while it is held at the operating position. The first locking means 220 are disposed respectively at the widthwise end portions of the upper end portions of the first opening-closing member 124. Each of the first locking means 220 is provided with an anchoring member 222, and a shaft portion 224 provided in the anchoring member 222 is pivotally mounted on the inside surface of the end wall of the first opening-closing member 124 (on the inside surface of the end wall 128 in the case of one first locking means 220, and on the inside surface of the end wall 130 in the case of the other first locking means 220). One end portion 222a of the anchoring member 222 acts as an operating portion, and is operated in the direction shown by an arrow 226 (Figure 1) when the anchoring member 222 is held in the released state. A claw portion 228 is provided in the other end portion of the anchoring member 222, and can projects upwardly through an opening 230 formed in the upper wall 138 and the inside wall 134 of the first opening-closing member 124. The anchoring member 222 further has provided therein a biasing spring (not shown) for biasing the anchoring member 222 in a direction opposite to the direction of arrow 226. Usually, the anchoring member 222 is held at a locked position (the position shown in Figures 1 and 2 and by a two-dot chain line 222 in Figure 7) when the action of the biasing spring causes the claw portion 228 to contact the opening end of the upper wall 138. In relation to the second opening-closing member 126, second locking means 232 are provided in order to releasably lock the second opening-closing member 126 into the above position. The second locking means 232 are provided at the widthwise end portions of the second opening-closing member 126, and have operative projecting portions 234 extending to the right in Figures 1 and 2 (one operative projecting portion 234 is provided in the end wall 182, and the other operative projecting portion 234, in the end wall 184). An outwardly projecting locking pin 236 is provided in the end portion of each of the operative projecting portions 234. In the illustrated embodiment, recesses are formed in the end walls 182 and 184 so as to enable the operative projecting portions 234 to be elastically deformed inwardly to a relatively large extent. A pair of plate pieces 240 (one of them is shown in Figure 2) are disposed in the inside surface of a right outside wall 238 (Figure 2) in the main body 2 of the machine in correspondence to the operative projecting portions 234. Each of the plate pieces 240 has formed therein a hole 242 capable of releasably receiving the pin 236 of the operative projecting portion 234. A biasing spring 244 which can be formed of, for example, a plate spring is disposed below the first opening-closing member 124. The biasing spring 244 is secured to a fixing piece 248 attached to a bottom wall 246 in the main body 2 of the machine. Its arcuately curving end portion acts on the bottom wall 136 of the first opening-closing 124 to bias the first opening-closing member 124 clockwise in Figures 1 and 2 about the pins 154 and 156 as a center. When locked by the first locking means 220 and the second locking means 232, the first opening-closing member 124 and the second opening-closing member 126 are kept in the state shown in Figures 1 and 2. Specifically, the anchoring members 222 in the first locking means 220 are held in the locked position, and the claw portions 228 projecting upwardly through the openings 230 engage the lower end portion of a cover member 250. As a result, the first opening-closing member 124 is locked releasably into the closing position while it is at the operative position. In this closed state, the first opening-closing member 124 is biased clockwise by the action of the biasing spring 244, and thus elastically held at the closing position. Furthermore, the pins 236 in the second locking means 232 are detachably received in the holes 242 of the plate pieces 240, and thus, the second opening-closing member 126 is locked into the closing position. In the above-mentioned state, a greater portion of the first feed passage 86 is defined by the inside surface of the first opening-closing member 124 and the outside surface of the second opening-closing member 126, as shown in Figure 1. A sheet material delivered from the first feed means 66 passes between the first opening-closing member 124 and the second opening-closing member 126 and further through guide ribs 252 formed in the inside surface of the cover member 250 and a feed roller 254, and is fed to the upstream end of the conveying passage. Most of one side of the second feed passage 96 is defined by the inside surface of the second opening-closing member 126, and a sheet material delivered from the second feed means 68 is guided by the second opening-closing member 126, passes between the guide ribs 252 and the feed roller 254, and is fed to the upstream end of the conveying passage 51. The illustrated embodiment has the following characteristic features in relation to the feeding of the sheet material from the first feed means 66. As can be understood from Figure 1, the sheet material delivered from the first feed means 66 acts so as to bias the first opening-closing member 124 clockwise in Figure 1 about the pins 154 and 156 as a center, or in other words, so as to cause the first opening-closing member 124 to be held at the above opening and closing positions. Accordingly, the first opening-closing member 124 accurately conducts the sheet material delivered from the first feed means 66 between the guide ribs 252 and the feed roller 254 without being displaced from the closing position by the sheet material. To open the first feed passage 86, the anchoring members 222 of the first locking means 220 are pivoted in the direction of arrow 226 through the openings formed in the outside wall 132 of the first opening-closing member 124, as shown in Figure 7. As a result, the anchoring members 222 are brought to the unlocked position shown in Figure 7 from the locking position, and the claw portions 228 are substantially received within the first opening-closing member 124 and disengaged from the cover member 250, to permit movement of the first opening-closing member 124. Thereafter, the first opening-closing member 124 is pivoted in the direction shown by an arrow 258 while it is moved in the direction shown by an arrow 256. When the first opening-closing member 124 is moved in the direction of arrow 256 from the above operating position, the pins 154 and 156 move to the right in Figure 7 within and along the holes 164 of the supporting plate pieces 162, and as the pins 154 and 156 abut with the other ends of the holes 164, the first opening-closing member 124 is held at the operating position past the position shown by the two-dot chain line 124A in Figure 7. When the first opening-closing member 124 is turned in the direction of arrow 258, it pivots clockwise around the pins 154 and 156 as a center. When the first opening-closing member 124 is held at the opening position shown by the solid line in Figure 7 while it is at the above removed position, the lower end of its outside wall 132 comes into contact with the upper surface of a table 260 on which the main body 2 of the machine is placed. As a result, the first opening-closing member 124 is held at the opening position at its removed position as shown in Figure 8 and by the solid line in Figure 7. It will be appreciated from Figure 7 that in the closed state, most of the first feed passage 86 is opened, and in the event of paper jamming in the first feed passage 86, the sheet material that has jammed up can be easily removed. In the open state, the pins 154 and 156 can be detached from the holes 162 and 164 by elastically deforming the supporting members 150 and 152 elastically, and the first opening-closing member 124 can be detached from the main body 2 of the machine. In the illustrated embodiment, the first opening-closing member 124 is constructed such that it is free to move between the operating position and the removed position, and when the first feed passage 86 is opened, the first opening-closing member 124 is moved to the removed position and held at the opening position. Accordingly, the first feed passage can be opened to a greater extent than when the first opening-closing member is constructed merely such that it is free to pivot between the opening position and the closing position, and it is much easier to remove the sheet material in the event of paper jamming. Furthermore, since in the illustrated embodiment, the biasing spring biases the first opening-closing member 124 clockwise toward the opening position, as can be seen from Figure 7, the first opening-closing member 124 can be easily pivoted toward the opening position by the biasing action of the biasing spring 244. Furthermore, since the biasing spring 244 also acts as a supporting guide during the movement of the first opening-closing member 124 between the operating position and the removed position, the first opening-closing member 124 can be smoothly moved in the direction of arrow 256 and in a direction opposite to it. To open the second feed passage 96 then, the operative protrusions 234 of the second locking means 232 are pressed inwardly through openings formed by positioning the first opening-closing member 124 at the above operating position. As a result, the operating protrusions 234 are elastically deformed inwardly from the locking position and the pins 236 are detached from the holes 242 of the plate pieces 240 to allow the second opening-closing member 126 to be free to pivot. direction shown by an arrow 262 (Figure 8) while it is elastically deformed inwardly. When the opening-closing member 126 is pivoted to the position shown in Figure 8 from the above closing position, the lower end portion of the lower wall 186 of the second opening-closing member 126 comes into contact with the introduction protrusion 148 of the first opening-closing member 124 at the closing position, whereby the second opening-closing member 126 is held at the opening position shown in Figure 8. It will be understood from Figure 8 that in this opening position, most of the second feed passage 96 is opened, and in the event of jamming in the second feed passage 96, the sheet material that has jammed up can be easily removed. In the illustrated embodiment, the first feed passage 86 can be opened to a greater extent than in the prior art, and in relation to it, by pivoting the second opening-closing member 126 to a relatively large extent, it comes into contact with the first opening-closing member 124. Accordingly, the second feed passage 96 can also be opened to a great extent. To return the second feed passage 96 so opened to the original state, the second opening-closing member 126 is pivoted in a direction opposite to the direction of arrow 262 to the above closing position, and then, the pins 236 in the second locking means 232 are brought into engagement with the holes 242 of the plate pieces 240. In order to return the opened first feed passage 86 to the original state, the first opening-closing member 124 is pivoted in the opposite direction shown by arrow 258 while it is moved in a direction opposite to the direction of arrow 256. As a result, the first opening-closing member 124 is held at the closing position while it is at the operative position. Thereafter, the claw portions 228 of the anchoring members 222 of the first locking means 220 are engaged with the cover member 250. The illustrated embodiment is further constructed as shown below in relation to the second locking means 232. Firstly, it is so constructed that when the second locking means 232 are in the locking condition and then the first opening-closing member 124 is locked into the closing position, it is virtually impossible to cancel the locking of the second locking means 232. With reference to Figure 9 in conjunction with Figures 2 and 3, outwardly projecting nearly triangular operative protrusions 264 and 266 are further provided in the outside surfaces of the end walls 128 and 130 of the first opening-closing member 124 in the illustrated embodiment. These operative protrusions 264 and 266 are disposed in correspondence to, and constructed so as to act on, the operative protrusions 234 in the second locking means 232. More specifically, when the second opening-closing member 126 is held at the closing position and locked by the second locking means 232 and thereafter the first opening-closing member 124 is pivoted to the closing position at the operating position and locked by the first locking means 220, the pair of end walls 128 and 130 of the first opening-closing member 124 are situated inwardly of the pair of end walls 182 and 184 of the second opening-closing member 126 as shown in Figure 9. In this state, the operative protrusion 264 provided in the end wall 128 acts on the inside surface of the operating protrusion 234 provided in one second locking means 232, and the operating protrusion 266 provided in the other end wall 130 acts on the inside surface of the operating protrusion 234 in the other second locking means 232. In this state, these operative protrusions 264 and 266 accurately prevent the operative protrusions 234 of the second locking means 232 from being elastically deformed inwardly. Consequently, it is virtually impossible to unlock the second locking means 232 and detach the pins 236 from the holes 242 of the plate pieces 240. Secondly, the first opening-closing member 124 is designed such that when the second opening-closing member 126 is not locked in the closing position by the second locking means 232, it is virtually impossible to pivot the first opening-closing member 124 to the closing position at the operating position. With reference to Figures 10 and 11, when the second opening-closing member 126 is pivoted toward, and near, the above closing position, the pins 236 provided in the operating protrusions 234 of the second locking means 232 is positioned inwardly of the plate piece 240 on the side of the main body 4 of the apparatus. When in this state the inward depressing pressure of the operative protrusions 234 is cancelled, the pins 236 abut with the inside surfaces of the plate pieces 240 without fitting in the holes 242. In this abutting state, the operative protrusions 234 in the second locking means 232 are elastically deformed inwardly, and their free end portions project inwardly inclinedly into the pivoting path of the first opening-closing member 124, as shown in Figure 11. Accordingly, when in this state the first opening-closing member 124 is pivoted toward the closing position, the opposite end portions (the end walls 128 and 130 in the illustrated embodiment) of the first opening-closing member 124 come into contact with the free end portions of the operative protrusions 234 which are elastically deformed inwardly, and consequently the first opening-closing member 124 cannot be brought to the closing position. The two structures described above with regared to the second locking means 232 (the structure in which when the second locking means 232 is locked and then the first opening-closing member 124 is locked in the closing position, it is virtually impossible to cancel the locking state of the second locking means 232, and the structure in which when the second opening-closing member 126 is not locked into the closing position by the second locking means 232, the first opening-closing means 124 cannot substantially be brought to the closing position) can also be applied to an apparatus of the type in which the first opening-closing member 124 is simply free to pivot between the opening position and the closing position. Modified examples of the method of mounting the first opening-closing member By mounting the first opening-closing member as shown in Figure 12 or 13, the same operation and result are achieved. In Figure 12 showing a first modified example of the method of mounting the first opening-closing member, the first opening-closing member 124' is mounted on the main body of the apparatus via a pair of linking members 268 (only one of them is shown). One linking member 268 is disposed on the side of one end of the first opening-closing member 124', and its one end is linked pivotally to one vertical base plate of the lower frame member via a pin 270. The other end of the linking member 268 is linked pivotally to one end wall 128' of the first opening-closing member 124'. The other linking member 268 is disposed on the side of the other end of the first opening-closing member 124', and its one end is pivotally linked to the other vertical base plate of the lower frame member via a pin while its other end is liked pivotally to the other end wall of the first opening-closing member 124' via a pin. To open the first feed passage in the first modified example, one releases the first locking means 220' and then moves the first opening-closing member 124' from the operating position shown by a solid line toward the removed position in the direction shown by an arrow 274 and at the same time, pivots it from the closing position shown by a solid line toward the opening position shown by a two-dot chain line in the direction shown by an arrow 276. When the first opening-closing member 124' is pivoted to the opening position at the above removed position, its outside surface comes into contact with the upper surface of the table 260' as shown by a two-dot chain line in Figure 12 to maintain the first opening-closing member 124' at the opening position. In mounting the first opening-closing member 124' as in the first modified example, too, the first opening-closing member 124' is moved toward the above-mentioned removed position at the time of opening the first feed passage and at the same time, pivoted toward the opening position. Accordingly, the first feed passage can be opened to a great extent as in the above-described embodiment. Figure 13 shows a second embodiment of the method of mounting the first opening-closing member. In the second modified embodiment, rail members 278 (one of which is shown) are provided in the inside surfaces of the pair of vertical base plates of the lower frame member. The rail member 278 is slightly inclined downwardly from one end (left side) to the other end (right side), and its other end portion extends downwardly in a nearly vertical direction. A pair of rollers 280 corresponding to one rail member 278 are rotatably mounted on the end wall 128'' of the first opening-closing member 124'', and although not shown, a pair of rollers 280 corresponding to the other rail member 278 are also rotatably mounted on the other end wall of the first opening-closing member 124''. The pair of rollers 280 are disposed vertically and positioned on both sides of the rail member 278 so as to hold them therebetween. Accordingly, the pair of rollers 280 can move along the rail member 278 while rotating. To prevent the pair of rollers 280 from being detached from the rail member 278, it is preferable to provide detachment preventing pieces 282 and 284 in both end portions of the rail member 278. When the mounting method in the second modified example is used, the first opening-closing member 124'' is free to move between an operative position (shown by a solid line) at which the rollers 280 are positioned at one end portion of the rail member 278 and a removed position (shown by a two-dot chain line) at which the rollers 280 are positioned at the other end portion of the rail member 278 and at the same time free to pivot between the closing position shown by the solid line and the opening position shown by the two-dot chain line. At the time of opening the first feed passage, the first opening-closing member 124'', after the first locking means 220'' is released, is moved toward the removed position in the direction shown by an arrow 286 and pivoted toward the opening position in the direction shown by an arrow 288. When it is pivoted to the opening position while it is at the removed position, the lower end portion of its outside comes into contact with the upper surface of the cable 260'' and is consequently held at the opening position. As a result, in the second modified embodiment, too, the first feed passage can be opened to a great extent.

Claims: An image-forming machine comprising a conveying passage (51) for conveying a sheet material through a transfer zone (48), a first (66) and a second (68) feed means for feeding the sheet material to the conveying passage (51), a first feed passage (86) for conducting the sheet material delivered from the first feed means (66) to the conveying passage (51) and a second feed passage (96) for conducting the sheet material delivered from the second feed means (68) to the conveying passage (51), characterized in that at least a greater portion of one side of the first feed passage (86) is defined by a first opening-closing member (124) and at least a greater portion of its other side is defined by one surface of a second opening-closing member (126), at least a greater portion of one side of the second feed passage (96) is defined by the other surface of the second opening-closing member (126), the first opening-closing member (124) is free to pivot between a closing position at which it defines one side of the first feed passage (86) and an opening position at which it opens the first feed passage (86), and the second opening-closing member (126) is free to pivot between a closing position at which its one surface defines the other side of the first feed passage (86) and its other surface defines the second feed passage (96) and an opening position at which it opens the second feed passage (96). The image-forming machine of claim 1, in which a pair of pins (154, 156) are provided in one of the first opening-closing member (124) and the main body (2) of the machine, and slender receiving portions (164) corresponding to the pair of pins (154, 156) are provided in the other of the first opening-closing member (124) and the main body (2) of the machine, and the pair of pins (154, 156) are respectively adapted to be received in the corresponding receiving portions (164) so that they are free to move relative to each other along the receiving portions (164) between an operating position in the main body (2) of the machine and a removed position removed from the operating position and are free to pivot relative to each other between the closing position and the opening position. The image-forming machine of claim 1 or 2, in which the first and second opening-closing members (124, 126) are constructed such that when the second opening-closing member (126) is not at the closing position, the first opening-closing member (124) cannot substantially be held at the closing position. The image-forming machine of any one of the claims 1 to 3, in which a first locking means (220) for releasably locking the first opening-closing member (124) into the closing position and a second locking means (232) for releasably locking the second opening-closing member (126) into the closing position are provided, and the first and second opening-closing members are constructed such that when the second opening-closing member (126) is not locked into the closing position by the second locking means (232), the first opening-closing member (124) cannot substantially be held at the closing position. The image-forming machine of claim 4, in which when, while the second opening-closing member (126) is not locked at the closing position by the second locking means (232), the first opening-closing member (124) is pivoted toward the closing position, the first opening-closing member (124) comes into contact with part of the second locking means (232), and cannot substantially be held at the closing position. The image-forming machine of claim 4 or 5, in which when the second opening-closing member (126) is locked at the closing position by the second locking means (232) and then the first opening-closing member (124) is locked at the closing position by the first locking means (220), the first opening-closing member (124) acts on part of the second locking means (232) and thus, the second locking means (232) cannot substantially be maintained in the lock-released state. The image-forming machine of claim 6, in which the second locking means (232) has an operating portion provided in the second opening-closing member (126) so that it can elastically be deformed between a locked state and a lock-released state; an engaging protrusion (264, 268) is provided in one of the main body of the machine on which the second opening-closing member (126) is mounted and the operating portion of the second locking means (232) and a receiving portion for detachably receiving the engaging protrusion is defined in the other of the main body and the operating portion; when the engaging protrusion in the second locking means is engaged with the receiving portion to lock the second opening-closing member (126) into the closing position and then the first opening-closing member (124) is locked into the closing position by the first locking means (220), the first opening-closing member (124) acts on the operating portion and thus, the operating portion cannot substantially be maintained lock-released state from the locked state. The image-forming machine of claim 2, in which a biasing spring (244) is disposed for biasing the first opening-closing member (124) toward the opening position, and the biasing spring (244) acts as a supporting guide when the first opening-closing member (124) is moved between the operating position and the removed position. The image-forming machine of claim 8, in which the first locking means (220) locks the first opening-closing member (124) into the closing position as a result of the opening-closing member (124) being biased toward the opening position by the biasing action of the biasing means (244); and the sheet material conveyed through the passage (86) acts so as to pivot the first opening-closing member (124) toward the opening position. The image-forming machine of any one of claims 1 to 9, in which the first feed means (66) and the second feed means (68) each include a cassette-receiving section (78, 88) defined within the main body (2) of the machine, a cassette (82, 92) having sheet materials placed therein and adapted to be detachably loaded into the cassette-receiving section (78, 88) and a feed roller (84, 94) disposed above the cassette-receiving section, and the inside surface of at least one of the first (124) and second (126) opening-closing members extends curvingly upwardly toward the conveying passage (51) from the cassette-receiving section (78, 88), and contact-preventing depressed portions (146, 196) for preventing both end portions of the leading end of the sheet material delivered from the cassette (82, 92) from coming into contact with the opening-closing member are provided at both end portions in the widthwise direction of the upstream end portions of said upwardly extending inside surface. The image-forming machine of claim 10, in which an introduction protrusion (148, 188) slightly projecting into the cassette-receiving section (78, 88) is provided at a central part in the widthwise direction of the upstream end of the inside surface of one of the first (124) and second (126) opening-closing members. The image-forming machine of any one of claims 1 to 11, in which the first opening-closing member (124) is detachably mounted on the main body (2) of the machine.

Inventors: FUCHI MASAMI, HAYASHI SHIGEKI, ISHIDA NAOYUKI, KUBOTA HIROSHI, MAKIURA YOSHINORI, NAKAMURA HIROAKI, OGIRI TADAKAZU, YAMAGUCHI KATSUHIDE, FUCHI, MASAMI, HAYASHI, SHIGEKI, ISHIDA, NAOYUKI, KUBOTA, HIROSHI, MAKIURA, YOSHINORI, NAKAMURA, HIROAKI, OGIRI, TADAKAZU, YAMAGUCHI, KATSUHIDE
Applicants: MITA INDUSTRIAL CO LTD, MITA INDUSTRIAL CO., LTD.
Application year: 1989
Main classification: G03G15
IPC codes: B65H5, B65H3, G03G21, G03G15