JP6060835B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus of a type that exposes a photoreceptor surface with an LED is known.

  For example, Patent Document 1 discloses an image forming apparatus that includes a plurality of LED units that are movable between an exposure position and a retracted position and that have a plurality of light emitting units arranged to expose a photosensitive drum.

  For example, in Patent Document 2, the LED print head (LPH) is advanced to an exposure position for exposing the photosensitive drum, and the LPH is retracted to a retracted position that is further away from the photosensitive drum than the exposure position. An image forming apparatus having an advance / retreat mechanism in each image forming unit is disclosed.

JP 2009-175416 A JP 2011-020414 A

  An object of the present invention is to provide an image forming apparatus in which parts required for retracting an exposure device are suppressed.

An image forming apparatus according to claim 1 is provided.
A plurality of image carriers each having an image formed thereon and each holding the image;
A plurality of exposure units provided in association with each of the plurality of image carriers, each exposing the surface of the corresponding image carrier;
Any of the plurality of exposure devices can be attached or detached, and the attached exposure device can be moved away from the exposure position where the image carrier is exposed, and the retracted position where the distance from the image carrier is larger than the exposure position. A plurality of insertion points provided in association with each of the plurality of exposure devices;
It is provided with.

An image forming apparatus according to a second aspect further includes the image forming apparatus according to the first aspect.
The number of the retracting devices is less than the number of the exposure devices.

An image forming apparatus according to a third aspect further includes the image forming apparatus according to the second aspect.
A biasing member that biases the exposure device from the retracted position to the exposure position;
The retractor is a member that retracts the exposure device to the retracted position against the biasing force of the biasing member as it is inserted into the insertion location.

An image forming apparatus according to claim 4
The retractor has a mechanical mechanism for retracting the exposure device to the retracted position, and the mechanism is operated after being inserted into the insertion location.

  According to the image forming apparatus of the first aspect, compared with the case where the present configuration is not provided, parts required for retracting the exposure device can be suppressed.

  According to the image forming apparatus of the second aspect, the convenience is high as compared with the case where the retracting device is not provided.

  According to the image forming apparatus of the third aspect, the configuration of the retracting device can be simplified as compared with the case where the configuration is not provided.

  According to the image forming apparatus of the fourth aspect, the certainty of the retracting operation is high as compared with the case where the present configuration is not provided.

1 is a schematic configuration diagram of a printer corresponding to a first embodiment of an image forming apparatus. It is sectional drawing which showed the structure of LPH. It is the enlarged view which expanded and showed the surrounding structure of the advancing / retreating operation part. It is a front view of the state where the retraction key was inserted in the insertion location. It is a side view of the state where the retraction key was inserted into the insertion location. It is a front view of the state which LPH retracted. It is a side view of the state which LPH retracted. It is a figure which shows the advancing / retreating operation part in 2nd Embodiment.

  A specific embodiment of the image forming apparatus of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a printer corresponding to the first embodiment of the image forming apparatus.

  A printer 1 shown in FIG. 1 is a so-called tandem color printer, and includes an image forming process unit 10 that forms an image corresponding to image data of each color, a control unit 30 that controls the operation of the entire printer 1, and, for example, An image processing unit 35 that is connected to an external device such as a personal computer (PC) 3 or an image reading device 4 and performs image processing on image data received from these devices, and a main power source 36 that supplies power to each unit. I have.

  The image forming process unit 10 includes four image forming units 11Y, 11M, 11C, and 11K (hereinafter collectively referred to simply as “image forming units 11”) arranged in parallel at regular intervals. It has been. Each image forming unit 11 includes a photosensitive drum 12 on which an electrostatic latent image or a toner image is formed, a charger 13 for charging the surface of the photosensitive drum 12, and the surface of the photosensitive drum 12 as image data. An LED print head (LPH) 14 that performs exposure on the basis, a developing device 15 that develops an electrostatic latent image formed on the photosensitive drum 12, and a cleaner 16 that cleans the surface of the photosensitive drum 12 after transfer. Yes. Note that the photosensitive drum 12 in the present embodiment includes a rotation shaft not shown in FIG. 1, and the axial direction from the front side (front side in the figure) to the rear side (back side in the figure) of the printer 1. It is arranged to face.

  The photoconductive drum 12 corresponds to an example of an image carrier according to the present invention, and the LPH 14 corresponds to an example of an exposure unit according to the present invention.

  Here, in each image forming unit 11, the photosensitive drum 12, the charger 13, and the cleaner 16 are an integrated module (hereinafter referred to as a photosensitive module PM). The photoconductor module PM is detachable from the printer 1 and is exchanged according to the life of the photoconductor drum 12 or the like. The photoreceptor module PM may be a module of only the photoreceptor drum 12 that does not include the charger 13 and the cleaner 16, or a module in which the developing device 15 is further integrated in addition to the charger 13 and the cleaner 16. It may be adopted. That is, as long as the photoconductor drum 12 is included, the photoconductor module PM can be combined with any component, but in the present embodiment, the photoconductor module PM and the LPH 14 are configured separately. It is said.

  On the other hand, the LPH 14 is not mounted on the photoconductor module PM, and each image forming unit 11 advances the LPH 14 to an exposure position for exposing the photoconductor drum 12, and the LPH 14 is more sensitive than the exposure position. An advancing / retreating operation unit 17 is provided for retracting to a retracted position separated from the body drum 12. Although details of the advance / retreat operation unit 17 will be described later, a retraction key 70 for retracting the LPH 14 by being inserted into the advance / retreat operation unit 17 is provided in the printer 1 at a storage location that does not interfere with other elements. The retraction key 70 can be inserted into the advance / retreat operation unit 17 of any image forming unit 11.

  Each image forming unit 11 has the same configuration except for the toner stored in the developing device 15. Each image forming unit 11 forms yellow (Y), magenta (M), cyan (C), and black (K) toner images.

  Further, the image forming process unit 10 performs intermediate transfer on the intermediate transfer belt 20 onto which the color toner images formed on the photosensitive drums 12 of the image forming units 11 are transferred, and the color toner images on the image forming units 11. A primary transfer roll 21 that is sequentially transferred to the belt 20, a secondary transfer roll 22 that collectively transfers the superimposed toner image transferred onto the intermediate transfer belt 20 onto a sheet as a recording material, and an image that is secondarily transferred onto the sheet. And a fixing device 45 for fixing the toner image.

  In the printer 1, the image forming process unit 10 performs an image forming operation based on various control signals supplied from the control unit 30. That is, image data input from the PC 3 or the image reading device 4 is subjected to image processing by the image processing unit 35 under the control of the control unit 30 and is supplied to each image forming unit 11 via an interface (not shown). The For example, in the black (K) image forming unit 11K, the photosensitive drum 12 is charged to a predetermined potential by the charger 13 while being rotated in the direction of arrow A, and transmitted from the image processing unit 35. Exposure is performed by the LPH 14 that emits light based on data representing a black component image in the image data. As a result, an electrostatic latent image related to a black (K) color image is formed on the photosensitive drum 12. The electrostatic latent image formed on the photosensitive drum 12 is developed by the developing device 15, and a black (K) toner image is formed on the photosensitive drum 12. Similarly, yellow (Y), magenta (M), and cyan (C) toner images are formed in the image forming units 11Y, 11M, and 11C of other colors, respectively.

  The respective color toner images formed by the respective image forming units 11 are sequentially electrostatically attracted by the primary transfer roll 21 onto the intermediate transfer belt 20 moving in the direction of arrow B to form a composite toner image in which the respective color toners are superimposed. Is done. The synthetic toner image on the intermediate transfer belt 20 is conveyed to a region (secondary transfer portion T) where the secondary transfer roll 22 is disposed as the intermediate transfer belt 20 moves. Further, the sheet is supplied from the sheet holding unit 40 to the secondary transfer unit T in accordance with the conveyance timing of the synthetic toner image by the intermediate transfer belt 20. The composite toner image is collectively electrostatically transferred onto the conveyed paper by the transfer electric field formed by the secondary transfer roll 22 in the secondary transfer portion T.

  Thereafter, the sheet on which the synthetic toner image has been electrostatically transferred is peeled off from the intermediate transfer belt 20 and conveyed to the fixing device 45. The synthesized toner image on the paper conveyed to the fixing device 45 is fixed on the paper by the fixing device 45 by a fixing process using heat and pressure. Then, the sheet on which the fixed image is formed is conveyed to the paper discharge stacking unit 41 provided in the discharge unit of the printer 1.

  On the other hand, toner (transfer residual toner) adhering to the intermediate transfer belt 20 after the secondary transfer is removed from the surface of the intermediate transfer belt 20 by the belt cleaner 25 after the completion of the secondary transfer to prepare for the next image forming cycle. In this way, image formation by the printer 1 is repeatedly executed for the number of printed sheets.

  FIG. 2 is a cross-sectional view showing the structure of the LPH 14.

  The LPH 14 is disposed below the photosensitive drum 12 in the printer 1 shown in FIG. 1 and exposes the photosensitive drum 12 from below.

  As shown in FIG. 2, the LPH 14 includes a housing 61, an LED array 63, an LED circuit board 62, a rod lens array 64, and a holder 65.

  The housing 61 is formed of a metal block such as aluminum or SUS or a sheet metal, and supports the LED circuit board 62.

  On the LED circuit board 62, an LED array 63, a signal generation circuit for driving the LED array 63, and the like are mounted.

  The rod lens array 64 forms an image of the light from the LED array 63 on the surface of the photosensitive drum 12, and is disposed along the axial direction of the photosensitive drum 12 and has a width in the rotation direction of the photosensitive drum 12. It is formed. The rod lens array 64 includes a plurality of gradient index lenses that form an erecting equal-magnification real image.

  The holder 65 is formed in a long shape and is disposed along the axial direction of the photosensitive drum 12, and supports the housing 61 and the rod lens array 64 and shields the LED array 63 from the outside. This makes it difficult for dust to adhere to the LED array 63 from the outside. The holder 65 supports the rod lens array 64 so that the light emitting point of the LED array 63 and the focal plane of the rod lens array 64 coincide.

  Here, the detail of the advancing / retreating operation part 17 mentioned above is demonstrated.

  FIG. 3 is an enlarged view showing the peripheral structure of the advance / retreat operation unit 17 in an enlarged manner.

  The advancing / retreating operation unit 17 is provided with a rotating member 80 that is rotatable about a shaft 81, and the rotating member 80 holds the LPH 14. The advancing / retreating operation unit 17 is also provided with a pushing spring 91 that pushes the rotating member 80 toward the photosensitive drum 12. The rotating member 80 and the LPH 14 are pushed toward the photosensitive drum 12 by the force of the pushing spring 91 and rotate around the shaft 81. Then, the positioning pin 66 protruding from the LPH 14 abuts against the bearing of the photoconductive drum 12 so that the distance between the LPH 14 and the photoconductive drum 12 becomes an appropriate distance for exposure. Thus, the position where the LPH 14 is at an appropriate distance for exposure with respect to the photosensitive drum 12 is the exposure position.

  The rotating member 80 has arms 82 and 83, and projections 84 and 85 are provided on the arms 82 and 83. The arms 82 and 83 rotate integrally with the rotating member 80, but the advancing / retreating operation unit 17 includes rails 92 and 93 provided independently of the rotating member 80 and the arms 82 and 83. The rails 92 and 93 are fixed in the printer 1 of FIG. 1 so that the rails 92 and 93 do not move even when the rotary member 80 or the arms 82 and 83 rotate. Note that the LPH 14 and the advancing / retreating operation unit 17 are detachable as exposure modules from the printer 1 for convenience of maintenance and the like, but detailed description thereof is omitted here.

  The retraction key 70 described above is inserted into an insertion portion 70 ′ provided between the rails 92 and 93 of the advance / retreat operation unit 17. When the user needs to retreat the LPH 14 as in the case of replacing the photoconductor module PM, for example, the user extracts the retraction key 70 from the above-mentioned storage location and inserts it into the insertion location 70 '. This insertion location 70 ′ corresponds to an example of the insertion location according to the present invention. Further, the push spring 91 corresponds to an example of an urging member according to the present invention, and the retraction key 70 corresponds to an example of an evacuation device according to the present invention.

  The operation when the retract key 70 is inserted into the insertion location 70 'will be described below.

  FIG. 4 is a front view of a state where the retraction key 70 is inserted into the insertion portion 70 ′, and FIG. 5 is a side view of a state where the retraction key 70 is inserted into the insertion portion 70 ′. FIG. 5 shows a side view seen from the right side of FIGS. 3 and 4, and illustration of the photosensitive drum 12 and the like is omitted in FIG. 5.

  4 and 5 show a state in which the retracting key is inserted but the LPH 14 remains in the exposure position and the positioning pin 66 remains in contact with the bearing of the photosensitive drum 12.

  The retraction key 70 is inserted in the direction of the arrow shown in FIG. The retraction key 70 has a simple structure in which two inclined plates 71 and 72 are overhanged by being divided in the front and rear in the insertion direction. Further, the two arms 82 and 83 of the rotating member 80 are also provided separately before and after the retraction key 70 in the insertion direction as shown in FIG. The inclined plate 71 provided on the rear side in the insertion direction corresponds to the arm 83 shown on the left side of FIGS. The inclined plate 72 provided on the front side corresponds to the arm 82 shown on the right side of FIGS. 3 and 4 among the two arms 82 and 83 of the rotating member 80.

  The retraction key 70 inserted by the user into the insertion portion 70 'is guided by the rails 92 and 93 and proceeds to the right in FIG. As a result, the two inclined plates 71 and 72 approach the protrusions 84 and 85 protruding from the corresponding arms 82 and 83, respectively.

  6 is a front view of the LPH 14 in a retracted state, and FIG. 7 is a side view of the LPH 14 in a retracted state. 7 shows a side view as viewed from the right side of FIG. 6. In FIG. 7, illustration of the photosensitive drum 12 and the like is omitted. Further, in FIGS. 6 and 7, the rails 92 and 93 are not shown.

  When the retraction key 70 is further depressed from the state shown in FIGS. 4 and 5, the retraction state shown in FIGS. That is, when the retraction key 70 is guided by a rail (not shown) and proceeds in the right direction in FIG. 7, the two inclined plates 71 and 72 projecting from the retraction key 70 correspond to the corresponding arms 82 and 83. It contacts each protrusion 84,85. Then, when the retraction key 70 is further pushed by the user, the projections 84 and 85 are pulled down along the inclination of the inclined plates 71 and 72 in FIGS. As a result, the arms 82 and 83 and the rotating member 80 rotate around the shaft 81 against the force of the pressing spring 91, and the LPH 14 moves to a retracted position farther from the photosensitive drum 12 than the exposure position. Moving. As shown in FIG. 6, the positioning pin 66 of the LPH 14 is also separated from the bearing of the photosensitive drum 12, and contact between the LPH 14 and the photosensitive drum 12 is avoided even when the photosensitive module PM is replaced.

  When the replacement of the photoconductor module PM is completed, the retraction key 70 is pulled out by the user from the state shown in FIGS. As a result, the protrusions 84 and 85 of the arms 82 and 83 are released from the inclined plates 71 and 72 of the retraction key 70, and the rotating member 80 and the LPH 14 are pushed up by the force of the pressing spring 91 to center on the shaft 81. As shown in FIG. As shown in FIG. 4, the positioning pin 66 hits the bearing of the photosensitive drum 12, and the LPH 14 returns to the exposure position again.

  Incidentally, although the printer 1 shown in FIG. 1 includes four image forming units 11Y, 11M, 11C, and 11K, the replacement of the photoconductor module PM and the like are executed by one image forming unit 11 at a time. Therefore, the retracted state shown in FIGS. 6 and 7 is not required simultaneously for the plurality of image forming units 11. For this reason, in the present embodiment, only one retraction key 70 is provided for the four image forming units 11Y, 11M, 11C, and 11K, thereby fulfilling a sufficient role. That is, one retraction key 70 is shared by the four image forming units 11Y, 11M, 11C, and 11K, and it can be said that the number of parts is reduced accordingly.

  Next, a second embodiment of the present invention will be described. This second embodiment is the same as the first embodiment described above except that the structure of the advancing / retreating operation unit is different. Therefore, the following description will focus on the differences from the first embodiment. Repeated explanation is omitted.

  FIG. 8 is a diagram illustrating an advance / retreat operation unit according to the second embodiment.

  8 shows the advancing / retreating operation unit 17 'viewed from the direction corresponding to the right side of FIG.

  In the second embodiment as well, the LPH 14 is held by the rotating member 80 as in the first embodiment. Although not shown, the rotating member 80 is pressed by the pressing spring 91 as in the first embodiment. The rotating member 80 of the second embodiment does not have the arms 82 and 83 as shown in FIG. 3 and the like, and the coupled protrusions 87 and 88 protrude.

  Also in the second embodiment, a rail 95 independent of the rotating member 80 is provided, and an insertion point 100 ′ is provided between the rail 95 and the rotating member 80. In the case of the second embodiment, the retractor 100 is inserted into the insertion location 100 ′. The retractor 100 is for retracting the LPH 14 by the user operating the operation lever 101 to be tilted.

  In addition to the operation lever 101 operated by the user, the retractor 100 includes coupling projections 102 and 103 coupled to the coupled projections 87 and 88 of the rotating member 80, and coupling projections 102 and 103 by operating the operation lever 101. A mechanism unit 104 incorporating a mechanical mechanism that moves up and down is provided. Detailed structures of the mechanism unit 104 and the operating lever 101 are the same as the structure described in the above-described Japanese Patent Application Laid-Open No. 2011-020414, and thus detailed description thereof is omitted here.

  The retractor 100 shown in FIG. 8 is detachable from the printer, like the retract key 70 of FIG. 1, and only one is prepared for the four image forming units 11Y, 11M, 11C, and 11K. Therefore, it can be freely attached to and detached from any of these four image forming units 11Y, 11M, 11C, and 11K. The retractor 100 corresponds to an example of a retractor having a mechanical mechanism according to the present invention.

  When the user inserts the retractor 100 into the insertion location 100 ′, the retractor 100 is guided by the rail 95 and proceeds to the right in FIG. 8. As a result, the coupling protrusions 102 and 103 of the retractor 100 are coupled to the coupled protrusions 87 and 88 of the rotating member 80. The coupling protrusions 102 and 103 and the coupled protrusions 87 and 88 are provided separately in front and rear in the insertion direction of the retractor 100, but the insertion direction front of the retractor 100 is not disturbed when the retractor 100 is attached or detached. The connecting protrusion 103 provided on the back is short and the connecting protrusion 102 provided on the rear side in the insertion direction is high. Even if the retractor 100 is inserted deeply and the coupling protrusions 102 and 103 and the coupled protrusions 87 and 88 are completely coupled to each other, unlike the first embodiment, the LPH 14 is at the exposure position unless the operation lever 101 is operated. It remains.

  When the operating lever 101 is operated after the retractor 100 is inserted and tilted to the left side in FIG. 8, the coupling protrusions 102 and 103 are pulled down in FIG. 8 by the movement of the mechanical mechanism incorporated in the mechanism unit 104. . As a result, the rotating member 80 and the LPH 14 are also pulled downward in FIG. 8 through the coupled projections 87 and 88 coupled to the coupling projections 102 and 103. As a result, the LPH 14 moves to a retracted position that is farther from the photosensitive drum 12 than the exposure position shown in FIG.

  When the user returns the operation lever 101 to the position shown in FIG. 8 from the state where the LPH 14 is retracted to the retracted position, the coupling protrusions 102 and 103 also return to the height shown in FIG. 8, and the rotary member 80 and the LPH 14 are also not shown. The position returns to the position shown in FIG. 8 by the force of the pressing spring. At this time, as in the first embodiment, the positioning pin 66 comes into contact with the bearing of the photosensitive drum 12, whereby the LPH 14 is positioned at an exposure position at a distance suitable for exposure with respect to the photosensitive drum 12.

  In the second embodiment, the LPH 14 is moved to the exposure position by the operation of the operation lever 101 even when the retractor 100 is inserted in the insertion portion 100 ′. Accordingly, in the second embodiment, a storage location different from the insertion location is not required as in the first embodiment, and if it is inserted into any of the four image forming units 11Y, 11M, 11C, and 11K. Good.

  As described above, also in the second embodiment, since only one retractor 100 is prepared for the four image forming units 11Y, 11M, 11C, and 11K, the retractor 100 includes four image forming units 11Y, 11M, 11C, and 11K are used together, and it can be said that the number of parts is suppressed accordingly.

  This is the end of the description of the specific embodiment of the present invention.

  In the description of each of the above embodiments, a tandem color printer is illustrated as an embodiment of the image forming apparatus of the present invention. However, the image forming apparatus of the present invention is a revolver type color printer or a monochrome printer. Also good. In addition to the printer, the image forming apparatus of the present invention may be a copier, a facsimile machine, or a multifunction machine.

  In the description of each of the above embodiments, a pressing spring is shown as an example of the biasing member according to the present invention. However, the biasing member according to the present invention may be a tension spring or rubber.

  In the description of each of the above embodiments, an example in which the movement between the exposure position and the retracted position is a rotational movement around the rotation axis is shown. However, the exposure position and the retracted position referred to in the present invention are described as follows. The movement between the two may be a parallel movement guided by a rail or the like.

  In the description of each of the above embodiments, an example in which one retractor according to the present invention is provided for four image forming units is shown. However, the image forming apparatus of the present invention includes four retractors. Two or three image forming units may be provided, or none may be provided, and a system engineer or the like may be provided when necessary.

1 Printer 11 Image Forming Unit 12 Photosensitive Drum 14 LED Print Head (LPH)
17 Advancing / retreating operation part 70 Retraction key 70 'insertion point 100 Retractor 100' insertion point

Claims (4)

A plurality of image carriers each having an image formed thereon and each holding the image;
A plurality of exposure units provided in association with each of the plurality of image carriers, each of which exposes the surface of the corresponding image carrier;
The exposure device can be attached to or detached from any of the plurality of exposure devices, and the attached exposure device is retracted at a distance greater than the exposure position from the exposure position at which the image holding member is exposed. A plurality of insertion points provided in association with the plurality of exposure devices, respectively, into which retraction instruments for retraction are inserted; and
An image forming apparatus comprising:   The image forming apparatus according to claim 1, wherein the number of the retracting devices is less than the number of the exposure devices. A biasing member that biases the exposure device from the retracted position to the exposure position;
3. The member according to claim 2, wherein the retracting device is a member that retracts the exposure device to the retracted position against the biasing force of the biasing member as it is inserted into the insertion location. Image forming apparatus.   3. The retractor has a mechanical mechanism for retracting the exposure device to the retracted position, and the mechanism is operated after being inserted into the insertion location. Image forming apparatus.

Images