JP2005298217A5 - - Google Patents

Description

Process unit

  The present invention relates to a process unit that is formed by assembling at least an image carrier to a unit case and is detachably attached to an image forming apparatus main body.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic vertical sectional view showing an example of an image forming apparatus. The image forming apparatus shown here is configured as a laser printer. Inside the image forming apparatus main body 1 is accommodated a drum-shaped photoconductor 2 which is an example of an image carrier that is rotatably supported by the image forming apparatus main body 1. During the image forming operation, the photosensitive member 2 is rotationally driven counterclockwise in FIG. 1, and at this time, the surface of the photosensitive member 2 is uniformly charged to a predetermined polarity by a charging roller 3 which is an example of a charging device. A voltage having a predetermined polarity is applied to the charging roller 3, and the charging roller 3 contacts the surface of the photosensitive member while rotating to charge the surface of the photosensitive member. A charging device including a charging blade or a corona discharger can also be used.

  The surface of the charged photoreceptor 2 is irradiated with light-modulated laser light L emitted from an image exposure apparatus configured as a laser optical system 4, thereby forming an electrostatic latent image on the surface of the photoreceptor. . This electrostatic latent image is visualized as a toner image by powdered toner carried and conveyed by the developing roller 6 of the developing device 5.

  On the other hand, a sheet feeding device 7 is disposed below the image forming apparatus main body 1, and a transfer sheet P, which is an example of a transfer material accommodated in the sheet feeding cassette 8, is fed by the rotation of the sheet feeding roller 9. 8 is sent out one by one. As shown by an arrow A, the fed transfer paper P is transferred to a registration roller pair 10 and a toner image formed on the surface of the photoconductor 2 at a timing to match the toner image formed on the surface of the photoconductor 2. 2, the toner image on the photosensitive member is transferred onto the surface of the transfer sheet P. At this time, the transfer roller 11 rotates while being in contact with the photosensitive member 2 via the transfer paper P, and a voltage having a polarity opposite to the charging polarity of the toner on the surface of the photosensitive member is applied to the transfer roller 11. The toner image on the surface is electrostatically transferred onto the surface of the transfer paper P. Instead of the transfer roller 11, a transfer device including a transfer blade, a transfer brush, or a corona discharger can be used.

  Transfer residual toner that is not transferred to the transfer paper P and adheres to the surface of the photoconductor is removed from the surface of the photoconductor by the cleaning member 13 of the cleaning device 12, and the surface is cleaned.

  The transfer paper P is separated from the photosensitive member 2 by the action of a separation device including the static elimination needle 15. The transfer paper P that has passed through the transfer portion in this manner is continuously conveyed in the direction of the arrow B and passes between the fixing roller 16 and the pressure roller 17 of the fixing device 14, and at this time, the transfer is performed by the action of heat and pressure. The unfixed toner image carried on the paper surface is fixed on the transfer paper. The transfer paper is then discharged onto a paper discharge tray 20 by a pair of paper discharge rollers 19 that are driven to rotate with the surface of the fixed toner image facing down. The image forming apparatus main body 1 of the present example includes an outer cover 21 and a main body frame 18, and a discharge tray 20 is configured by the upper wall of the outer cover 21.

  The photosensitive member 2, the charging roller 3, the developing device 5, and the cleaning device 12 are configured as an integral process unit 22. The process unit 22 is detachably loaded in the image forming apparatus main body 1. The unit case 25 itself of the process unit 22 constitutes a developer container 26 of the developing device 5, in which a developer made of toner is accommodated. Similarly, a cleaning case 27 is formed by the unit case 25 itself. The transfer residual toner collected from the body 2 is accommodated.

  As shown also in FIG. 3, a part of the photoreceptor 2 is exposed outside the unit case through the case opening 29 formed in the unit case 25 of the process unit 22, and faces the transfer roller 11. The photoreceptor 2 is rotatably supported by the unit case 25 and is rotationally driven by a driving device (not shown) provided in the image forming apparatus main body 1. In this way, the photoreceptor 2 is accommodated in the image forming apparatus main body 1 and is supported rotatably with respect to the image forming apparatus main body 1 via the unit case 25.

  The process unit 22 is also referred to as a process cartridge or an image forming unit. The process unit 22 of this example includes an image carrier made of the photosensitive member 2, a charging roller 3, a developing device 5, a cleaning device 12, and a unit case 25. The process unit includes at least It is only necessary to have an image carrier and a unit case in which the image carrier is assembled. In general, a process unit is often configured by assembling a charging device, at least one process element of a cleaning device and a developing device, and an image carrier to a unit case.

  The operator who operates the image forming apparatus shown in FIG. 1 is usually located on the right side of the image forming apparatus in FIG. Therefore, the image forming apparatus main body side on the right side in FIG. 1 is the front side, and the open / close cover 23 is provided on the front side of the image forming apparatus main body 1 with respect to the image forming apparatus main body 1. The pivot pin 24 is supported so as to be rotatable and openable. The opening / closing cover 23 normally occupies a closed position for closing the opening 28 (see FIG. 2) in the front portion of the image forming apparatus main body 1 as shown in FIG. The pivot pins 24 protrude from the side plates 30 and 30A (FIG. 3) of the main body frame 18 constituting the image forming apparatus main body 1, respectively. When the operator stands on the front side of the image forming apparatus main body 1, the side plates 30 and 30A of the main body frame 18 are located on the left and right sides of the operator, respectively.

  When an operator located on the front side of the image forming apparatus main body 1 grabs the upper part of the opening / closing cover 23 and pulls it to the near side, the opening / closing cover 23 moves around the pivot pin 24 as shown in FIG. By rotating in the C direction, the opening 28 of the image forming apparatus main body 1 is opened, thereby opening the transfer path of the transfer paper. The transfer roller 11 and the charge removal needle 15 are supported by the opening / closing cover 23. Therefore, when the opening / closing cover 23 is opened as shown in FIG. 2, the transfer roller 11 and the charge removal needle 15 are separated from the image forming apparatus main body 1 together with the opening / closing cover 23. .

  Since the transfer paper transport path is opened by opening the opening / closing cover 23 in this manner, the transfer paper jammed here can be easily removed. Further, the process unit 22, the fixing device 14, or other elements can be removed and replaced from the front side of the image forming apparatus main body 1 with the opening / closing cover 23 opened. When the toner in the developer container 26 runs out or the cleaning case 27 is full of toner, the process unit 22 can be replaced with a new process unit. Further, the paper feeding device 7 can also be pulled out from the front side of the image forming apparatus main body 1 to the front side (right side in FIG. 1), and transfer paper can be replenished to the paper feeding cassette 8. After replenishing the transfer paper, the paper feeding device 7 is pushed into the back side (left side in FIG. 1), and this is set at the position shown in FIG.

  When the opening / closing cover 23 is rotated in the direction of arrow D and brought to the closed position shown in FIG. 1, the transfer roller 11 faces the photosensitive member 2 and the toner formed on the surface of the photosensitive member as described above. The image can be transferred onto the transfer paper P.

  As described above, the image forming apparatus of this example has an image carrier on which a toner image is formed on the surface, and a transfer device that transfers the toner image on the surface of the image carrier to a transfer material, and at least the image carrier. The process unit is configured by assembling the body to the unit case, and the process unit is detachably mounted on the image forming apparatus main body.

  Here, as described above, the transfer paper P delivered from the paper feeding device 7 passes through the conveyance path between the unit case 25 and the opening / closing cover 23 as shown by an arrow A in FIG. And passed through the nip portion of the transfer roller 11 and then fed into the fixing device 14. As described above, the transfer paper P is conveyed along the unit case 25 and is sent to the transfer portion between the photosensitive member 2 and the transfer roller 11, so that the transfer paper P is transferred so that the transfer paper P is correctly conveyed. It is necessary to form a guide for guiding the unit in the unit case 25.

  However, if only the guides formed on the unit case 25 are configured to guide the surface of the transfer paper P that has exited the registration roller pair 10, the length of the guide along the transfer paper transport direction increases, and the process unit 22. Is attached to and detached from the image forming apparatus main body 1, the guide may interfere with the image forming apparatus main body or elements on the main body side, and the process unit 22 may be difficult to attach or detach. .

  Therefore, in the image forming apparatus of this example, as shown in FIGS. 1 to 3, the first guide 31 is formed in the unit case 25, and the second guide 32 is provided in the image forming apparatus portion other than the process unit 22. The transfer paper is guided by the cooperative action of these guides 31 and 32. In this way, the length of the first guide 31 formed in the unit case 25 in the transfer paper conveyance direction can be kept small, and the first guide 31 can be used as another element when the process unit 22 is attached or detached. It is possible to prevent the trouble that the process unit 22 cannot be attached and detached due to interference.

  In the illustrated example, as shown in FIG. 3, the end portions of the support member 33 are fixed to the left and right side plates 30 and 30A of the main body frame 18, and the second guide 32 is fixed to the upper surface thereof. Thus, in the image forming apparatus of this example, the second guide 32 is supported by the support member 33 that constitutes a part of the main body frame 18. The second guide 32 is provided in the image forming apparatus portion other than the process unit 22.

  The transfer paper P conveyed in the direction of arrow A in FIG. 1 moves while being guided by the second guide 32 and the first guide 31 on the same side surface, that is, the surface onto which the toner image is transferred. It is fed between the body 2 and the transfer roller 11. The back surface of the transfer paper is guided by a guide piece 34 formed integrally with the opening / closing cover 23.

  As described above, in the image forming apparatus of the present example, the first and the second guides guide the surface on the same side of the transfer material conveyed to the transfer unit to the unit case 25 and the image forming apparatus part other than the process unit 22. Second guides 31 and 32 are provided, respectively.

  At this time, as can be seen from FIGS. 3 to 5, the first guide 31 formed in the unit case 25 itself is formed with a plurality of notches 35, and a transfer material guide portion is formed between the notches 35. 36 is formed. The plurality of transfer material guides 36 are arranged at intervals from each other in a direction orthogonal to the conveyance direction A of the transfer paper P.

  On the other hand, the second guide 32 protrudes integrally on the upper surface of the base 37 extending in a direction orthogonal to the conveyance direction A of the transfer paper P, and is spaced apart from each other in the orthogonal direction. And a tongue-shaped transfer material guide portion 38 arranged in the manner described above. Further, the transfer material guide portions 36 and 38 of the first and second guides 31 and 32 are arranged in a state where they are not in contact with each other, as shown in FIGS. As shown in FIG. 4 with double diagonal lines, the transfer material guide portions 36 and 38 of the first and second guides 31 and 32 enter each other with their respective parts overlapping. is there.

  As described above, the first and second guides 31 and 32 are each a plurality of transfer material guides 36 and 38 that are spaced apart from each other in a direction orthogonal to the transfer material transport direction A. The transfer material guides 36 or 38 of one guide 31 or 32 of the first and second guides 31 and 32 are respectively connected to the transfer material guides 38 or 36 of the other guide 32 or 31. They are arranged in a state where they are not in contact with each other. Moreover, each of the transfer material guide portions 36 of the first guide 31 is formed by a unit case surface between the notches 35 formed in the unit case 25. 3 and 4, each notch 35 includes a pair of unit case side wall portions 50 facing each other at an interval in a direction orthogonal to the transfer material transport direction A, and the pair of unit case side walls 50. The unit case connecting wall 51 is connected to the unit case side wall 50. Further, the notches 35 are formed in the notches 35 so that the transfer material guide portions 38 of the second guide 32 provided in the image forming apparatus portion other than the process unit can enter without being in contact with each other. Yes.

  As shown in FIG. 7, assuming that the first guide 31 and the second guide 32 are arranged without overlapping each other, the manufacturing unit 22 of these guides 31 and 32 and the process unit 22 with respect to the main body frame 18 are arranged. There is a possibility that a gap G or a step H may be formed between the guides 31 and 32 due to a deviation in assembling. In such a case, when a transfer sheet made of a weak sheet such as a thin sheet is used, the leading end of the transfer sheet may enter the gap G as indicated by an arrow E, causing a paper jam. Further, when the rear end portion of the transfer paper passes through the step H, the rear end portion flutters and the impact of the impact on the toner image transferred onto the transfer paper is unavoidable.

  On the other hand, when the transfer material guide portions 36 and 38 of the first and second guides 31 and 32 are assembled so as to enter each other as in the image forming apparatus of this example, each of the first and second guides 31 and 32 is assembled. In addition, when the shape and size of the second guides 31 and 32 vary somewhat, or when the process unit 22 is set in the image forming apparatus body 1, the assembled state of the process unit 22 with respect to the image forming apparatus body 1 is slightly out of order. However, it is possible to prevent a gap or a step between the first and second guides 31 and 32 from being formed in the transfer paper conveyance direction, and to convey the transfer paper correctly in a predetermined direction A while smoothly guiding the transfer paper. can do. The guide surfaces of the first and second guides 31 and 32 facing the transfer paper transport path are continuous in the transfer paper transport direction. That is, as illustrated in FIG. 4, the guide surface F <b> 1 configured by the base portion 37 of the second guide 32, the next guide surface F <b> 2 configured by the transfer material guide portions 38 of the second guide 32, and the second A guide surface F3 constituted by each transfer material guide portion 36 of one guide 31 and a guide surface F4 on the upper side of the first guide 31 are continuously located in the transfer paper conveyance direction, and the transfer paper is guided by these guide papers. Smoothly guided by the surface.

  Further, each transfer material guide portion 36 of the first guide 31 and each transfer material guide portion 38 of the second guide 32 are positioned so as to enter each other without being in contact with each other. The two guides 32 are not in contact at all. For this reason, even if the shape and size of the first and second guides 31 and 32, particularly the transfer material guides 36 and 38, or their arrangement positions are somewhat out of order due to variations in manufacturing, the process unit 22 Is set in the image forming apparatus main body 1, the first and second guides 31 and 32 interfere with each other so that the setting becomes difficult or incapable of causing the inconvenience. Even if the accuracy in manufacturing the first and second guides 31 and 32 is not particularly increased, the process unit 22 can be mounted on the image forming apparatus main body 1 without hindrance, thereby preventing an increase in cost of the image forming apparatus. It can be done.

  As described above, each transfer material guide portion 36 of the first guide 31 has a part thereof, that is, a portion indicated by a double oblique line in FIG. 4, between each transfer material guide portion 38 of the second guide 32. The transfer material guides 38 of the second guide 32 are also partly located, that is, the portions with double diagonal lines in FIG. 4 of the transfer material guides 36 of the first guide 31. Located in between. As a result, the various advantages described above can be obtained. As shown in FIGS. 8 and 9, the transfer material guide portions 36 of the first guide 31 and the transfer material guide portions 38 of the second guide 32. Have tip portions 39, 40, and particularly when the tip portions 39, 40 are pointed, one of the tip portions 39 is each transfer material guide portion 38 of the second guide 32 as shown in FIG. S1 protrudes without being positioned between them, and the other end portion 40 protrudes only by S2 without being positioned between the transfer material guide portions 36 of the first guide 31 as shown in FIG. Steps H1 and H2 are formed between the first and second guides 31 and 32, and the leading edge of the transfer paper is caught on the step H1, or the trailing edge of the transfer paper falls on the step H2, and the transfer is performed. There is a possibility that an impact is applied to the paper and the toner image is disturbed.

  Therefore, in the image forming apparatus of this example, as shown in FIGS. 4 and 5, the leading end portion 40 of each transfer material guide portion 38 of the second guide 32 is replaced with each transfer material guide portion of the first guide 31. It is located in a state where it has entered between 36. Similarly, the leading end portions 39 of the transfer material guide portions 36 of the first guide 31 are positioned so as to enter between the transfer material guide portions 38 of the second guide 32. 8 and 9 between the first and second guides 31 and 32 even when each of the transfer material guides has the sharp end portions 39 and 40. Such a step can be prevented, the leading edge of the transfer paper is caught and the trailing edge is prevented from falling, and high transfer reliability of the transfer paper can be ensured.

  By the way, there are many types of image forming apparatuses, and a dedicated process unit 22 suitable for the function of each type of image forming apparatus is mounted on the image forming apparatus main body 1 and used. However, the process unit 22 for each type of image forming apparatus is different in its function and performance, but its appearance is very similar, and it is often impossible to determine by just looking at these. Therefore, in particular, a general user sometimes attaches a process unit that is not suitable for the image forming apparatus used by the user to the main body of the image forming apparatus. If such a situation occurs, the quality of the completed image is significantly degraded.

  In order to prevent the occurrence of such troubles, in the image forming apparatus of this example, an inappropriate process unit is used in the image forming apparatus main body 1 by using the first and second guides 31 and 32 described above. It is configured so that it cannot be installed.

  FIG. 6 is an explanatory view showing an example. As described above, the second guide 32 provided on the image forming apparatus main body side has a plurality of transfer material guide portions 38 arranged at predetermined intervals. On the other hand, a notch 35 between the transfer material guide portions 36 of the first guide 31 is provided in the unit case 25 of the appropriate process unit 22 that is used by being attached to the image forming apparatus main body having the second guide 32. Are formed at positions corresponding to the respective transfer material guide portions 38 of the second guide 32. Therefore, when the appropriate process unit 22 is mounted on the image forming apparatus main body, the notches 35 are aligned with the transfer material guide portions 38 of the second guide 32, and the appropriate process unit 22 is formed without any trouble. It can be set on the device body.

  On the other hand, the notches 35A between the transfer material guide portions 36A of the first guide 31A formed in the unit case 25A of the inappropriate process unit 22A that should not be attached to the image forming apparatus main body are on the image forming apparatus main body side. The second guide 32 is disposed so as not to match each transfer material guide portion 38. For this reason, even if an operator mistakenly tries to attach the inappropriate process unit 22A to the image forming apparatus main body, the notch 35A does not match the transfer material guide portion 38 on the image forming apparatus main body side, and the inappropriate process unit 22A. Cannot be set in the main body of the image forming apparatus. Therefore, the operator immediately notices that he / she tried to set the wrong process unit 22A and can prevent the erroneous setting.

  The size, form, etc. of the first guide of the improper process unit may be different from those of the first guide of the proper process unit to prevent erroneous setting of the improper process unit.

  As described above, in the image forming apparatus of this example, when the second guide 32 tries to attach an inappropriate process unit 22A other than the appropriate process unit 22 to the image forming apparatus main body 1, this inappropriate process. The configuration is set so as to interfere with the first guide 31A formed in the unit case 25A of the unit 22A and make it impossible to mount the inappropriate process unit 22A.

  In the example described above, the present invention is applied to a guide for guiding a transfer sheet sent to a transfer unit. However, the present invention can also be applied to guides provided at various other locations. For example, as described in JP-A-5-281797, each of the above-described configurations can be employed as a guide for guiding a transfer sheet onto which a toner image has been transferred to a fixing device.

  The present invention can also be applied to various types of image forming apparatuses other than the image forming apparatus as shown in FIG. 1. For example, an image carrier on which a toner image is formed is an intermediate in which a toner image is transferred from a photoreceptor. The present invention can be widely applied to an image forming apparatus that is a transfer body, an image forming apparatus other than a printer, or a multifunction machine.

1 is a schematic sectional view of an image forming apparatus. FIG. 2 is a schematic cross-sectional view of the image forming apparatus when an opening / closing cover is opened. It is a perspective view which shows a process unit and a 2nd guide. FIG. 4 is a partially enlarged view of FIG. 1, which is a cross-sectional view corresponding to a view taken along line IV-IV of FIG. 3. FIG. 5 is a cross-sectional view similar to FIG. 4 corresponding to a view taken along line VV in FIG. 3. FIG. 6 is an explanatory diagram that makes it clear that an appropriate process unit can be attached to the image forming apparatus main body and an inappropriate process unit cannot be attached. It is a figure explaining the malfunction when each transfer material guide part of the 1st guide and each transfer material guide part of the 2nd guide do not enter mutually. It is a figure explaining the malfunction when the front-end | tip part of each transfer material guide part of a 1st guide cannot enter between each transfer material guide part of a 2nd guide. It is a figure explaining the malfunction when the front-end | tip part of each transfer material guide part of a 2nd guide cannot enter between each transfer material guide part of a 1st guide.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus main body 22 Process unit 22A Process unit 25 Unit case 25A Unit case 31 Guide 31A Guide 35 Notch 36 Transfer material guide part 38 Transfer material guide part 50 Unit case side wall part 51 Unit case connection wall part

Claims (2)

In a process unit comprising at least an image carrier assembled to a unit case and detachably attached to an image forming apparatus main body,
A guide for guiding the transfer material conveyed to the transfer unit is provided in the unit case, and the guide includes a plurality of transfer material guide units arranged at intervals from each other in a direction orthogonal to the transfer material conveyance direction. Each of the transfer material guides is formed by a unit case surface between notches formed in the unit case, and the notches are spaced from each other in a direction perpendicular to the transfer material transport direction. A process unit characterized in that it is defined by a pair of unit case side walls facing each other and a unit case connection wall connecting the pair of unit case side walls. 2. The process unit according to claim 1, wherein the notch is formed so that each transfer material guide provided in an image forming apparatus other than the process unit can enter the notch without contact.