JP4950351B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to a latent image carrier unit that includes at least a latent image carrier and is detachable from a main body of an image forming apparatus, and an image forming apparatus using the same.

  Conventionally, as this type of image forming apparatus, the one described in Patent Document 1 is known. The image forming apparatus includes a photosensitive unit as a latent image carrier unit that can be attached to and detached from the image forming apparatus main body. This photoconductor unit holds a photoconductor as a latent image carrier and a charging roller and a cleaning member, which are members disposed around the photoconductor, as a unit in a common casing. A first positioning protrusion and a second positioning protrusion are respectively provided on both side surfaces of the casing of the photosensitive unit. On the other hand, each of the two side plates erected so as to face each other at a predetermined distance in the image forming apparatus main body has a first slit engaged with the first positioning protrusion and a second positioning protrusion. A second slit that engages with the portion is formed. When paying attention to one side surface of the photoconductor unit, the photoconductor unit attaches / detaches the unit in the longitudinal direction of the first slit in a state where its first positioning protrusion is engaged with the first slit of the apparatus main body side plate. It is pushed in the direction and attached to the image forming apparatus main body. At this time, the positioning in the attachment / detachment direction is performed in the main body of the image forming apparatus by abutting the first positioning protrusion, which slides in the first slit, against the end of the first slit. Further, immediately before this positioning, the second positioning protrusion of its own is engaged with the second slit of the apparatus main body side plate. As a result, the photosensitive unit is positioned even at a location different from the first positioning protrusion. Similarly, on the other side surface of the photosensitive unit, the first positioning protrusion of the photosensitive unit abuts against the end of the other first slit in the image forming apparatus main body. Then, the second positioning projection of the photosensitive unit engages with the other second slit in the image forming apparatus main body.

  In such a configuration, the entire unit is positioned by positioning the photoconductor unit in the image forming apparatus main body at two positions of the first positioning protrusion and the second positioning protrusion that are different from each other on both side surfaces. The posture can be corrected.

  However, such a configuration has a problem that it is difficult to reduce the size of the image forming apparatus main body for the following reason. That is, the photosensitive unit is desired to be flattened with the recent miniaturization of the image forming apparatus. In particular, in a so-called tandem type color image forming apparatus using a plurality of photoconductor units that form toner images of different colors, flattening of each unit is an important factor for downsizing the apparatus main body. This is because the unit installation space can be made compact by adopting a layout in which flat photoconductor units are arranged in the thickness direction. In such a layout, it is assumed that each photosensitive unit is slid in the unit thickness direction in the image forming apparatus main body and is detachably attached to the image forming apparatus main body. Then, for example, although it is desired to replace only the third unit from the front, first, it is necessary to pull out the first and second units from the front from the inside of the apparatus main body. For this reason, a configuration is adopted in which each photoconductor unit is detachable independently by sliding in a direction substantially perpendicular to the unit thickness direction. On the other hand, the first positioning protrusions and the second positioning protrusions formed on both side surfaces of the photosensitive unit respectively maintain a desired positioning accuracy and have a strength that can withstand an impact when the unit is mounted. Since it is necessary to do so, a certain size is absolutely necessary. In order to engage the relatively large first positioning protrusion and the second positioning protrusion with the individual slits on both side surfaces of the photosensitive unit that slides in a direction substantially perpendicular to the unit thickness direction, respectively. Therefore, these protrusions must be arranged in the thickness direction on the side surface of the unit. Then, it becomes difficult to reduce the thickness of the photosensitive unit, that is, to flatten the unit.

  The present invention has been made in view of the above background, and an object of the present invention is to provide an image forming apparatus in which the latent image carrier unit can be made flatter than in the past.

In order to achieve the above object, a first aspect of the present invention provides a latent image carrier unit that includes a latent image carrier that carries a latent image on the surface and is detachable from the main body of the image forming apparatus. A latent image writing unit for writing the latent image; and a developing unit for developing the latent image with toner. The latent image carrier units are provided on two opposing surfaces of the image forming apparatus main body, respectively. A first positioning projection that engages with the groove or the slit, the groove or the slit has an abutted portion that abuts against the first positioning projection, and the latent image carrier unit includes: When the image forming apparatus main body is mounted, the abutting portion and the first positioning protrusion abut against each other, so that the image forming apparatus main body in the image forming apparatus main body of the latent image carrier unit. The positioning in the attachment / detachment direction with respect to In the image forming apparatus, an information storage circuit that stores predetermined information, an exposed electrode that is electrically connected to the information storage circuit and exposed to the outside, and the first positioning protrusion are arranged in the attachment / detachment direction. A second positioning projection for positioning the latent image carrier unit at a shifted position is provided on the latent image carrier unit, and when the latent image carrier unit is mounted on the image forming apparatus main body, the second positioning protrusion is provided. The protrusion is engaged with the groove or the slit engaged with the first positioning protrusion by shifting the position in the attaching / detaching direction with respect to the first positioning protrusion. In the image forming apparatus main body, a contact electrode that contacts the exposed electrode of the latent image carrier unit in a position where the first positioning protrusion is in contact with the abutted portion of the image forming apparatus main body. In contact with each other That via the the exposed electrode and the contact electrode, and a control means disposed in the image forming apparatus main body, so as to perform information communication with said information storage circuit, corresponding to said two surfaces, Apart from the combination of the first positioning projection and the second positioning projection and the groove or the slit, at least one of the two side surfaces of the latent image carrier unit, the latent image carrier unit Movement permitting engaging portions that engage with each other so as to allow movement in the attachment / detachment direction are provided in the latent image carrier unit and the image forming apparatus main body, respectively. For at least one of the side surfaces, the movement-permissible engaging portion is provided in one region with a virtual straight line connecting the first positioning projection and the second positioning projection as a boundary, and the exposure is performed in the other region. Electrode provided It is characterized by using the thing.
Further, the invention of claim 2, pushing the image forming apparatus according to claim 1, the latent image bearing member unit in the process of mounting to the image forming apparatus main body, the first positioning projection on the abutted portion Before the hit, the movement allowable engagement portion of the latent image carrier unit and the movement allowable engagement portion of the image forming apparatus main body are engaged with each other.
According to a third aspect of the present invention, in the image forming apparatus according to the second aspect, for each of the two side surfaces of the latent image carrier unit, the movement permission member is connected to the latent image carrier unit and the image forming apparatus main body. A plurality of combinations of joint portions are provided .
Also, the invention of claim 4, in any one of the image forming apparatus according to claim 1 to 3, as the latent image carrier unit, out of the entire area of the unit housing surface, is mounted to the image forming apparatus main body In the process, an area that is rubbed with the contact electrode of the main body of the image forming apparatus is subjected to a low friction process.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, a plurality of combinations of the exposed electrode and the contact electrode are provided in the latent image carrier unit and the main body of the image forming apparatus. It is characterized by this.
According to a sixth aspect of the present invention, in the image forming apparatus of the fifth aspect , the latent image is formed as a layout of a combination of the plurality of exposed electrodes and the plurality of contact electrodes individually corresponding to the exposed electrodes. In the process of mounting the carrier unit on the image forming apparatus main body, a layout is adopted in which the plurality of exposed electrodes are moved to the contact positions corresponding to the contact electrodes without contacting the contact electrodes not corresponding to the exposure electrodes. It is characterized by this.
According to a seventh aspect of the present invention, in the image forming apparatus according to any one of the first to sixth aspects, at least one of the exposed electrode and the contact electrode extends in the attaching / detaching direction. It is a feature.
The invention according to claim 8 is the image forming apparatus according to any one of claims 1 to 7 , wherein the attaching / detaching direction is shifted from a vertical direction.
According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect , the rotational moment of the drive transmission gear in the latent image carrier unit and between the latent image carrier unit and the main body of the image forming apparatus. Due to the rotational moment of the drive transmission gear, the rotational force applied to the latent image carrier unit with the contact point between the first positioning projection and the abutted portion serving as a fulcrum, The attachment / detachment direction is inclined with respect to the vertical direction.
According to a tenth aspect of the present invention, in the image forming apparatus according to any one of the first to ninth aspects, the latent image carrier is supported so as to be rotatable about a shaft member. The positioning projection is provided at the end of the shaft member in the axial direction .

  In these inventions, the first positioning protrusion and the second positioning protrusion are engaged with the same groove or slit on each of the two opposing side surfaces of the latent image carrier unit. Even if the portions are arranged at substantially the same position in the unit thickness direction, both protrusions can be engaged with the grooves or slits as the unit moves. In such a configuration, since it is not necessary to dispose the first positioning protrusion and the second positioning protrusion greatly shifted in the unit thickness direction, both the protrusions are disposed largely shifted in the unit thickness direction and are individually provided. The latent image carrier unit can be flattened as compared with the prior art in which the grooves or slits are engaged. Even if the first positioning protrusion and the second positioning protrusion are engaged with the same groove or slit, the second positioning protrusion is different from the first positioning protrusion due to contact with the inner wall of the groove or slit. Positioned at different positions. For this reason, as in the case where both protrusions engage with different grooves and slits, positioning of the entire unit and correction of the posture can be performed.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 2 is an enlarged configuration diagram illustrating a K photoconductor unit of the printer. The perspective view which shows an example of the image forming apparatus which performs an internal maintenance by the front cover opening / closing system. The perspective view which shows an example of the image forming apparatus which performs an internal maintenance by the left cover opening / closing system. The perspective view which shows an example of the image forming apparatus which performs an internal maintenance by an upper cover opening / closing system. FIG. 3 is a schematic diagram illustrating an opening / closing operation of an upper cover of the printer according to the embodiment. FIG. 3 is a partial perspective view illustrating a Y photoconductor unit of the printer. FIG. 3 is a perspective view showing four photoconductor units in the housing of the printer. FIG. 3 is a left side view illustrating a Y photoconductor unit of the printer.

Hereinafter, as an image forming apparatus to which the present invention is applied, an embodiment of an electrophotographic printer (hereinafter simply referred to as a printer) will be described.
First, the basic configuration of the printer will be described. FIG. 1 is a schematic configuration diagram showing the printer. In this figure, the printer includes four photosensitive units 1Y, M, C, and K for forming toner images of yellow, magenta, cyan, and black (hereinafter referred to as Y, M, C, and K). ing. These use Y, M, C, and K toners of different colors as the image forming material, but the other configurations are the same and are replaced when the lifetime is reached. Taking a photoconductor unit 1K for forming a K toner image as an example, as shown in FIG. 2, a drum-shaped photoconductor 2K as a latent image carrier, a drum cleaning device 3K, a charge eliminating device (not shown), a charging device. 4K, developing device 5K and the like. The photosensitive unit 1K, which is an image forming unit, can be attached to and detached from the printer body, so that consumable parts can be replaced at a time.

  The charging device 4K uniformly charges the surface of the photoreceptor 2K that is rotated clockwise in the drawing by a driving unit (not shown). The uniformly charged surface of the photosensitive member 2K is exposed and scanned by the laser beam L and carries an electrostatic latent image for K. The electrostatic latent image for K is developed into a K toner image by the developing device 5K using K toner. Then, intermediate transfer is performed on an intermediate transfer belt 36 described later. The drum cleaning device 3K removes the transfer residual toner adhering to the surface of the photoreceptor 2K after the intermediate transfer process. The static eliminator neutralizes residual charges on the photoreceptor 2K after cleaning. By this charge removal, the surface of the photoreceptor 2K is initialized and prepared for the next image formation. In the other color photoconductor units (1Y, M, C), (Y, M, C) toner images are similarly formed on the photoconductors (2Y, M, C), and an intermediate transfer belt 36 to be described later. Intermediate transfer is performed on the top.

  The developing device 5K includes a vertically long hopper 6K that stores K toner (not shown) and a developing unit 7K. In the hopper 6K, an agitator 8K that is rotationally driven by a driving means (not shown), an agitation paddle 9K that is rotationally driven by a driving means (not shown) vertically below, and rotated by a driving means (not shown) below the vertical direction. A toner supply roller 10K to be driven is disposed. The K toner in the hopper 6K moves toward the toner supply roller 10K by its own weight while being stirred by the rotational drive of the agitator 8K and the stirring paddle 9K. The toner supply roller 10K has a metal cored bar and a roller portion made of foamed resin or the like coated on the surface of the metal core roller 10K, while adhering K toner in the hopper portion 6K to the surface of the roller portion. Rotate.

  In the developing unit 7K of the developing device 5K, a developing roller 11K that rotates while contacting the photoreceptor 2K and the toner supply roller 10K, and a thinning blade 12K that contacts the tip of the developing roller 11K are disposed. Yes. The K toner adhered to the toner supply roller 10K in the hopper 6K is supplied to the surface of the development roller 11K at the contact portion between the development roller 11K and the toner supply roller 10K. When the supplied K toner passes through the contact position between the roller and the thinning blade 12K as the developing roller 11K rotates, the layer thickness on the roller surface is regulated. Then, the K toner after the layer thickness regulation adheres to the electrostatic latent image for K on the surface of the photosensitive member 2K in the developing region which is a contact portion between the developing roller 11K and the photosensitive member 2K. By this adhesion, the electrostatic latent image for K is developed into a K toner image.

  Although the photoconductor unit for K has been described with reference to FIG. 2, the Y, M, and C photoconductor units 1Y, M, and C are also subjected to Y, M, and C on the surface of the photoconductors 2Y, M, and C by the same process. M and C toner images are formed.

  In FIG. 1 described above, an optical writing unit 90 is disposed above the photosensitive units 1Y, 1M, 1C, and 1K in the vertical direction. The optical writing unit 90, which is a latent image writing means, uses the laser light L emitted from the laser diode based on the image information to uniformly charge the photosensitive members 2Y, M, and C in the photosensitive units 1Y, M, C, and K. C and K are optically scanned. By this optical scanning, electrostatic latent images for Y, M, C, and K are formed on the photoreceptors 2Y, M, C, and K. The optical writing unit 90 is a photosensitive member that passes through a plurality of optical lenses and mirrors while deflecting laser light (L) emitted from a light source in a main scanning direction by a polygon mirror that is rotationally driven by a polygon motor (not shown). Is irradiated. You may employ | adopt what performs optical writing by the LED light emitted from several LED of the LED array.

  Below the photosensitive units 1Y, 1M, 1C, and 1K, there is disposed a transfer unit 35 that moves the endless intermediate transfer belt 16 endlessly in the counterclockwise direction in the drawing. In addition to the intermediate transfer belt 36, the transfer unit 35 serving as transfer means includes a driving roller 37, a driven roller 38, four primary transfer rollers 39Y, 39M, 39C, and 40K, a secondary transfer roller 40, a belt cleaning device 41, a cleaning device. A backup roller 42 and the like are provided.

  The intermediate transfer belt 36 is stretched by a driving roller 37, a driven roller 38, a cleaning backup roller 42, and four primary transfer rollers 39Y, 39M, 39C, and 39K disposed inside the loop. Then, it is moved endlessly in the same direction by the rotational force of the drive roller 37 that is driven to rotate in the counterclockwise direction in the figure by a drive means (not shown).

  The four primary transfer rollers 39Y, 39M, 39C, and 39K sandwich the intermediate transfer belt 36 that is moved endlessly in this manner between the photoreceptors 2Y, 2M, 2C, and 2K. By this sandwiching, primary transfer nips for Y, M, C, and K where the front surface of the intermediate transfer belt 36 and the photoreceptors 2Y, 2M, 2C, and 2K abut are formed.

  A primary transfer bias is applied to each of the primary transfer rollers 39Y, 39M, 39C, and 39K by a transfer bias power source (not shown), whereby electrostatic latent images on the photoreceptors 2Y, 2M, 2C, and 2K, A transfer electric field is formed between the primary transfer rollers 39Y, 39M, 39C, and 39K. Instead of the primary transfer rollers 39Y, 39M, 39C, and 39K, a transfer charger, a transfer brush, or the like may be employed.

  When Y toner formed on the surface of the photoreceptor 2Y of the photoreceptor unit 1Y for Y enters the above-described primary transfer nip for Y as the photoreceptor 2Y rotates, due to the action of the transfer electric field and nip pressure, Primary transfer is performed from the photoreceptor 2Y onto the intermediate transfer belt. The intermediate transfer belt 36 on which the Y toner image has been primarily transferred in this way passes through the primary transfer nip for M, C, K along with the endless movement thereof, and the photoreceptors 2M, C, K. The upper M, C, and K toner images are sequentially superimposed on the Y toner image and primarily transferred. A four-color toner image is formed on the intermediate transfer belt 36 by this superimposing primary transfer.

  The secondary transfer roller 40 of the transfer unit 35 is disposed outside the loop of the intermediate transfer belt 36, and the intermediate transfer belt 36 is sandwiched between the secondary transfer roller 40 and the driven roller 38 inside the loop. By this sandwiching, a secondary transfer nip where the front surface of the intermediate transfer belt 36 and the secondary transfer roller 40 abut is formed. A secondary transfer bias is applied to the secondary transfer roller 40 by a transfer bias power source (not shown). By this application, a secondary transfer electric field is formed between the secondary transfer roller 40 and the driven roller connected to the ground.

  Below the transfer unit 35 in the vertical direction, a paper feed cassette 50 that stores a plurality of recording papers P in a bundle of paper is slidably attached to the printer housing. In the paper feed cassette 50, a paper feed roller 50a is brought into contact with the uppermost recording paper P of the paper bundle, and the recording paper is rotated by rotating it in a counterclockwise direction in the drawing at a predetermined timing. P is sent out toward the paper feed path 51.

  A registration roller pair 52 is disposed near the end of the paper feed path 51. The registration roller pair 52 stops the rotation of both rollers as soon as the recording paper P delivered from the paper feed cassette 50 is sandwiched between the rollers. Then, rotation driving is restarted at a timing at which the sandwiched recording paper P can be synchronized with the four-color toner image on the intermediate transfer belt 36 in the above-described secondary transfer nip, and the recording paper P is directed to the secondary transfer nip. Send it out.

  The four-color toner image on the intermediate transfer belt 36 brought into close contact with the recording paper P at the secondary transfer nip is secondarily transferred onto the recording paper P under the influence of the secondary transfer electric field and nip pressure, and the recording paper Combined with the white color of P, a full color toner image is obtained. When the recording paper P having the full-color toner image formed on the surface in this way passes through the secondary transfer nip, the recording paper P is separated from the secondary transfer roller 40 and the intermediate transfer belt 36 by the curvature. Then, it is sent to a fixing device 54 described later via a post-transfer conveyance path 53.

  Transfer residual toner that has not been transferred to the recording paper P adheres to the intermediate transfer belt 36 after passing through the secondary transfer nip. This is cleaned from the belt surface by a belt cleaning device 41 in contact with the front surface of the intermediate transfer belt 36. A cleaning backup roller 42 disposed inside the loop of the intermediate transfer belt 36 backs up the cleaning of the belt by the belt cleaning device 41 from the inside of the loop.

  The fixing device 54 forms a fixing nip with a fixing roller 54a containing a heat source such as a halogen lamp (not shown) and a pressure roller 54b that rotates while contacting the fixing roller 54a with a predetermined pressure. The recording paper P fed into the fixing device 54 is sandwiched between the fixing nips so that the unfixed toner image carrying surface is in close contact with the fixing roller 54a. Then, the toner in the toner image is softened by the influence of heating and pressurization, and the full color image is fixed.

  The recording paper P discharged from the fixing device 54 passes through the post-fixing conveyance path 55 and then reaches the branch point between the paper discharge path 56 and the pre-reversal conveyance path 61. On the side of the post-fixing conveyance path 55, a switching claw 62 that is rotationally driven about a rotation shaft 62a is disposed. By the rotation, the vicinity of the end of the post-fixing conveyance path 55 is closed. Or open it. At the timing when the recording paper P is sent out from the fixing device 54, the switching claw 62 stops at the rotation position indicated by the solid line in the drawing, and the vicinity of the end of the post-fixing conveyance path 55 is opened. Therefore, the recording paper P enters the paper discharge path 56 from the conveyance path 55 after fixing, and is sandwiched between the rollers of the paper discharge roller pair 57.

  When the single-sided print mode is set by an input operation to an operation unit including a numeric keypad (not shown) or a control signal sent from a personal computer (not shown), the recording sandwiched between the paper discharge roller pair 57 is set. The paper P is discharged out of the machine as it is. Then, it is stacked on the stack portion that is the upper surface of the upper cover 70 of the housing.

  On the other hand, when the duplex printing mode is set, the trailing edge of the recording paper P conveyed through the paper discharge path 36 while the front end is sandwiched between the paper discharge roller pair 57 passes through the post-fixing conveyance path 55. The switching claw 62 is rotated to the position of the one-dot chain line in the drawing, and the vicinity of the end of the post-fixing conveyance path 55 is closed. At substantially the same time, the paper discharge roller pair 57 starts to rotate in the reverse direction. Then, the recording paper P is conveyed while the rear end side is directed to the top, and enters the pre-reversal conveyance path 61.

  FIG. 1 shows the printer from the left side. The near side in the direction perpendicular to the drawing is the left side of the printer, and the far side is the right side. Further, the right side of the printer is a front side and the left side is a back side. The right end portion of the housing of the printer is a reversing unit 60 that can be opened and closed with respect to the housing body by rotating about a rotation shaft 60a.

  When the paper discharge roller pair 57 rotates in the reverse direction, the recording paper P enters the pre-reversal conveyance path 61 of the reversing unit 60 and is conveyed from the upper side to the lower side in the vertical direction. Then, after passing between the rollers of the pair of reverse conveying rollers 63, it enters the reverse conveying path 64 that is curved in a semicircular shape. Furthermore, while the upper and lower surfaces are reversed as the sheet is conveyed along the curved shape, the traveling direction from the upper side in the vertical direction to the lower side is also reversed, and conveyed from the lower side in the vertical direction toward the upper side. Is done. Thereafter, the toner enters the secondary transfer nip again through the above-described paper feed path 51. Then, after the full-color image is secondarily transferred collectively to the other surface, the post-transfer conveyance path 53, the fixing device 54, the post-fixation conveyance path 55, the paper discharge path 56, and the paper discharge roller pair 57 are sequentially passed. And discharged outside the machine.

  The reversing unit 60 described above has an external cover 65 and a rocking body 66. Specifically, the outer cover 65 of the reversing unit 60 is supported so as to rotate about a rotation shaft 60a provided in the housing of the printer main body. By this rotation, the outer cover 65 opens and closes with respect to the housing together with the swinging body 66 held therein. As shown by the dotted line in the figure, when the outer cover 65 is opened together with the swinging body 66 therein, the paper feed path 51 formed between the reversing unit 60 and the printer main body, the secondary transfer nip, and after the transfer. The conveyance path 53, the fixing nip, the post-fixing conveyance path 55, and the paper discharge path 56 are divided into two parts and exposed to the outside. Thus, jammed paper in the paper feed path 51, the secondary transfer nip, the post-transfer conveyance path 53, the fixing nip, the post-fixation conveyance path 55, and the paper discharge path 56 can be easily removed.

  The swinging body 66 is supported by the external cover 65 so as to rotate around a swinging shaft (not shown) provided in the external cover 65 in a state where the external cover 65 is opened. When the swinging body 66 is opened with respect to the external cover 65 by this rotation, the pre-reversal conveyance path 61 and the reverse conveyance path 64 are vertically divided into two and exposed to the outside. As a result, the jammed paper in the pre-reversal conveyance path 61 and the reversal conveyance path 64 can be easily removed.

  An upper cover 70 of the printer housing is supported so as to be rotatable about a shaft member 71 as indicated by an arrow in the figure, and opens to the housing by rotating counterclockwise in the figure. It becomes a state. And the upper opening of a housing is exposed greatly.

  By the way, in recent image forming apparatuses, it is desired that the internal components and apparatuses can be attached and detached without impairing the downsizing, weight reduction, and operability of the image forming apparatus. As a method for attaching and detaching parts and apparatuses, as shown in FIG. 3, the method is performed by opening the front cover provided at the front end (the end in the direction of arrow F in the figure) of the housing of the image forming apparatus, FIG. As shown in FIG. 2, a method of opening the left cover provided at the left end of the housing can be considered. Moreover, as shown in FIG. 5, the method of opening and opening the upper cover provided in the upper side edge part of the housing is also considered. For parts and devices that are relatively frequently attached and detached, it is desirable to employ a method in which the upper cover is opened as shown in FIG. Without taking an unreasonable posture such as squatting, bending your back, or bending down, you can check the attachment and detachment operation while looking at the inside of the housing from the upper side, reducing the work load and suppressing the occurrence of operation mistakes. Because it can. One of the reasons is that the upper part of the image forming apparatus is often used as a paper discharge tray or mounted with a scanner and is likely to be in a position with excellent visibility.

  In the printer according to the present embodiment, the four photosensitive units 1Y, 1M, 1C, and 1K shown in FIG. This is because they are replaced when the toner in the developing device runs out. Considering a configuration in which these photoconductor units 1Y, 1M, 1C, and 1K are attached and detached by the upper cover opening method as shown in FIG. 5, the most important layout conditions of the photoconductor units 1Y, 1M, 1C, and 1K are as follows. The flat units are arranged side by side in the thickness direction. If they are arranged side by side rather than side by side, for example, in order to replace the third unit from the top, it is necessary to attach and detach not only that unit but also the first and second units from the top that do not require replacement. This is because the operability is remarkably deteriorated.

  For this reason, when a horizontal layout is adopted for the four photoconductor units 1Y, 1M, 1C, and 1K, the intermediate transfer belt 36 is brought into contact with the horizontal photoconductors 2Y, 2M, 2C, and 2K. In addition, as shown in FIG. Then, the four photoconductor units 1Y, 1M, 1C, and 1K arranged side by side are arranged above the intermediate transfer belt 16 in the horizontally long position as shown in FIG. 1, or the layout of FIG. Conversely, it is disposed below the intermediate transfer belt 36.

  Here, in the case where the optical writing unit 90 is disposed below the intermediate transfer belt 36, the optical writing unit 90 is in a horizontally long posture so that optical scanning with respect to the four photosensitive members 2Y, 2M, 2C, and 2K can be performed. It is necessary to dispose below the body unit. Contrary to the layout shown in FIG. 1, the optical writing unit 90, each photosensitive unit (1 </ b> Y to K), and the intermediate transfer belt 16 are sequentially stacked from the lower side to the upper side in the vertical direction. However, in the configuration in which the recording paper P is conveyed from the lower side to the upper side in the vertical direction, the fixing device 54 needs to be provided above the intermediate transfer belt 36 that forms the secondary transfer nip. If it is adopted, the left side of the fixing device 54 in the figure becomes a blank space. For this reason, it is difficult to reduce the size and space of the apparatus.

  Therefore, in the printer according to the present embodiment, as shown in FIG. 1, a layout in which the four photoconductor units 1Y, 1M, 1C, and 1K are arranged side by side and disposed above the intermediate transfer belt 36 in the landscape orientation. Adopted. In such a layout, as shown in the drawing, the horizontally long optical writing unit is disposed above the four photosensitive units 1Y, 1M, 1C, and 1K. Then, the four photoconductor units 1Y, 1M, 1C, and 1K and the optical writing unit 90 can be disposed on the side of the fixing device 90 as shown in the figure to avoid the generation of blank spaces.

  On the other hand, regardless of whether the photoconductor units arranged side by side are arranged above or below the horizontally oriented intermediate transfer belt 36, the optical writing unit 90 or It becomes necessary to retract the intermediate transfer belt 36 from the position facing each photoconductor unit. For example, when each photoconductor unit is disposed above the intermediate transfer belt 36 as in this printer, the optical writing unit 90 is connected to each photoconductor unit (1Y to K) as shown in FIG. It will be arranged above. In such a layout, even if the upper cover 70 is opened with respect to the housing body, the optical writing unit 90 is in the way, and the respective photosensitive body units immediately below cannot be exposed. For this reason, it is necessary to retract the optical writing unit 90 from right above each photoconductor unit before performing the attaching / detaching operation on each photoconductor unit. Unlike the configuration shown in FIG. 1, when each photoconductor unit is arranged below the intermediate transfer belt 36, the transfer belt 36 is positioned directly above each photoconductor unit. For this reason, it is necessary to retract the intermediate transfer belt 36 from directly above each photoconductor unit prior to attaching or detaching each photoconductor unit.

  In this printer, as described above, from the viewpoint of miniaturization and space saving, each photoconductor unit is disposed above the intermediate transfer belt 36, and the optical writing unit 90 is further disposed thereon. Therefore, it is necessary to retract the optical writing unit 90 from right above each photoconductor unit. Therefore, in this printer, as shown in FIG. 6, the optical writing unit 90 is held on the lower surface of the upper cover 70, and retracted from right above each photoconductor unit as the upper cover 70 is opened and closed. Or set it right above.

Next, a characteristic configuration of the printer will be described.
FIG. 7 is a partial perspective view showing the Y photoconductor unit 1Y of the printer. In the figure, the photoconductor unit 1Y is set in a printer main body (not shown) in such a posture that the photoconductor axial direction (not shown) which is the longitudinal direction thereof extends in the horizontal direction. And the length of a unit width direction (henceforth a unit thickness direction) is a flat shape considerably small compared with a unit longitudinal direction and a height direction.

  A first positioning protrusion 14Y, a second positioning protrusion 15Y, a slide guide protrusion 16Y, and a model determination protrusion 17Y protrude from the surface of the case on the left side case 13Y of the casing of the photoreceptor unit 1Y. It is provided as follows. Further, an IC chip 18Y as an information storage circuit, a plurality of exposed electrodes 19Y, a protective sheet 20Y, and the like are also provided.

  The first positioning protrusion 14Y protrudes from the vicinity of the lower end of the left side case 13Y and at the center in the case thickness direction, and has a hollow cylindrical cap shape. The left case 13Y is provided with a not-shown photoreceptor bearing that receives a not-shown photoreceptor axis in the unit. Although not shown in the figure, the photosensitive member shaft protrudes outward from the surface of the case through the photosensitive member bearing provided in the case. The cylindrical cap-shaped first positioning protrusion 14Y covers a protruding portion of the shaft member of the photosensitive member from the case surface. That is, the first positioning protrusion 14Y is formed at the position of the photosensitive member axis. When the photoreceptor unit 1Y is set in the printer body, the photoreceptor unit 1Y is positioned at the position of the photoreceptor axis by the first positioning protrusion 14Y.

  The second positioning protrusion 15Y protrudes from the upper side of the left side case 13Y and at the center in the case thickness direction. The slide guide protrusion 16Y has a rail-like shape extending between the vicinity of the first positioning protrusion 14 and the vicinity of the second positioning protrusion 15 in the unit height direction. Further, the model discriminating protrusion 17Y is provided in the vicinity of the side of the second positioning protrusion 15Y in the unit height direction.

  In the drawing, only the left end portion of both end portions (unit left end portion and right end portion) in the longitudinal direction of the photosensitive unit 1Y is shown, but a left side case 13Y is also provided in a right side case (not shown) provided at the right end portion. The same 1st positioning protrusion, 2nd positioning protrusion, and the slide guide protrusion are provided. In addition, the right side case is provided with a color identification protrusion, which will be described later, instead of being provided with the model identification protrusion 17Y.

  The IC chip 18Y fixed to the left side case 13Y stores information unique to each product of the photoreceptor unit 1Y, such as a unit ID number, a unit operating time, and a manufacturing date. The plurality of exposed electrodes 19Y provided on the left side case 13Y are individually connected to a plurality of input / output terminals (not shown) of the IC chip 18Y.

  FIG. 8 is a perspective view showing four photoreceptor units 1Y, 1M, 1C, and 1K in the printer casing. In the figure, a housing of the printer main body includes a left side plate 95 as two members so as to oppose each other at a predetermined distance in the left-right direction of the printer (the photoconductor unit extending direction in the figure). A right side plate 98 is erected. As shown in the figure, the photoconductor units 1Y, 1M, 1C, and 1K are set so as to be bridged between the two side plates in a posture in which the longitudinal direction of the photoconductor units 1Y, M, C, and K is along the opposing direction of the left side plate 95 and the right side plate 98. The

  The left side plate 95 of the printer body is provided with a slit 96Y extending in a direction slightly inclined from the vertical direction so as to cut out the upper end of the left side plate 95. The slit 96Y is for guiding the Y photoconductor unit 1Y to the set position. The left side plate 95 is provided with similar slits (not shown) for M, C, and K, respectively, in addition to those for Y. Also, in the same figure, it could not be shown because it was hidden by each photoconductor unit, but the right side plate 98 is also provided with similar slits for Y, M, C, K.

  When the Y photoconductor unit 1Y is mounted on the printer main body, the photoconductor unit 1Y having a posture in which the unit longitudinal direction is aligned with the side plate facing direction of the printer main body is dropped from the upper side to the lower side of the printer. Go. Then, the first positioning protrusion 14Y formed near the lower end of the left side case 13Y of the photoreceptor unit 1Y is inserted into the entrance of the slit 96Y provided on the left side plate 95 of the printer body. At the same time, the first positioning protrusion formed near the lower end of the right side case (not shown) of the photoreceptor unit 1Y is inserted into the entrance of the Y slit (not shown) provided on the right side plate 98 of the printer body.

  Next, the first positioning protrusion 14Y is slid in the unit mounting direction from the upper side to the lower side in the slit 96Y while further dropping the photoconductor unit 1Y in the same posture. At the same time, the other first positioning protrusion provided on the right side case (not shown) of the photosensitive unit 1Y is also slid in the other slit. Then, the rail-shaped slide guide protrusion 16Y provided on the left side case 13Y of the photoreceptor unit 1Y immediately enters the entrance of the slit 96Y and starts to slide within the slit 96Y. At the same time, the other slide guide protrusion provided on the right side case (not shown) also enters the other slit provided on the right side plate 98 of the printer body and starts sliding.

  When the photoreceptor unit 1Y is further lowered downward, the rear end of the slide guide protrusion 16Y passes through the entrance of the slit 96Y. At the same time, the rear end of the slide guide protrusion provided on the right side case (not shown) of the photosensitive unit 1Y passes through the entrance of the other slit provided on the right side plate 98 of the printer body. Then, the second positioning projection 15Y provided on the left side case 13Y of the photoreceptor unit 1Y enters the entrance of the slit 96Y and starts sliding within the slit 96Y. At the same time, the other second positioning projection provided on the right side case (not shown) of the photoconductor unit 1Y enters the entrance of the other slit provided on the right side plate 98 of the printer body, Start sliding in the slit.

  When the photoreceptor unit 1Y is further lowered downward, the first positioning protrusion 14Y provided near the lower end of the left side case 13Y eventually comes into contact with the lower end inner wall of the slit 96Y that is the abutted part. At the same time, the other first positioning protrusion provided near the lower end of the right-side case (not shown) of the photosensitive unit 1Y is connected to the lower inner wall of the other slit provided on the right-side plate 98 of the printer body ( It hits the abutted part. Due to these bumps, the photosensitive unit 1Y is positioned in the longitudinal direction (unit attaching / detaching direction) of the slit 96Y (and the other slit) in the printer casing. At this time, the second positioning projection 15Y in the slit 96Y is positioned at a position different from the first positioning projection 14Y by contact with the inner wall of the slit 96Y. As a result, the photoreceptor unit 1Y is positioned and corrected in its posture.

  When the slide guide protrusion 16Y is not provided, the photosensitive unit 1Y is moved in the process of dropping the photosensitive unit 1Y further downward after the first positioning protrusion 14Y is inserted into the slit 96Y. Depending on the posture (angle), the second positioning protrusion 15Y may abut against the upper end of the left side plate 95. On the other hand, if the slide guide projection 16Y is provided, the second positioning projection 15Y is controlled by restricting the dropping posture of the photoreceptor unit 1Y by the engagement of the slide guide projection 16Y and the slit 96Y. It is possible to guide smoothly toward the slit 96Y. As a result, the setability of the photoreceptor unit 1Y can be improved.

  In this printer having such a configuration, the first positioning protrusion 14Y and the second positioning protrusion 15Y of the photoreceptor unit 1Y are engaged with the same slit 96Y provided on the left side plate 95 of the printer body. Thus, it is not necessary to dispose the first positioning protrusion 14Y and the second positioning protrusion 15Y by being greatly shifted in the unit thickness direction. As a result, the first positioning protrusion 14Y and the second positioning protrusion 15Y are arranged so as to be largely shifted in the unit thickness direction and engaged with the individual slits, respectively, compared to the conventional case. Can be flattened. For the same reason, the M, C, and K photoconductor units 1M, C, and K can be flattened as compared with the related art.

  Although the example in which the first positioning protrusion 14Y and the second positioning protrusion 15Y are engaged with the slit 96Y has been described, the first positioning protrusion 14Y and the second positioning protrusion 15Y may be engaged with a groove extending in the unit mounting direction.

  Further, in this printer, the photoreceptor units 1Y, 1M, 1C, and 1K are flattened for the reasons described above, but each unit still requires a certain thickness. In this printer, a configuration for avoiding erroneous mounting of a unit or acquiring unit individual information is added using this certain thickness. Hereinafter, those configurations will be described.

  On the left side plate 95 of the printer main body, a heterogeneous unit blocking engagement portion 97Y is provided beside the entrance of the slit 96Y. The different model unit blocking engaging portion 97Y engages with the model discriminating protrusion 17Y provided on the left side case 13Y of the photoreceptor unit 1Y, thereby avoiding erroneous mounting of the photoreceptor unit. ing.

  Specifically, various types of image forming apparatuses using a photoconductor unit are on the market, and there is a possibility that a photoconductor unit for another model is mistakenly attached to the printer. In particular, the preceding model and the successor model released from the same manufacturer are similar in size and shape of the photosensitive unit, and thus this type of erroneous mounting is likely to occur. Even if the model is suitable, in the case of using each color photoconductor unit as in this printer, for example, the photoconductor unit 1K for K is mistaken for the mounting position of the photoconductor unit 1Y for Y. There is also a risk of wearing.

  Therefore, in this printer, for the purpose of avoiding such erroneous mounting, a model discriminating projection 17Y and a color discriminating projection (not shown) are provided on the photosensitive unit 1Y, and a different model unit blocking engagement portion 97Y or the like. A different color unit blocking engagement portion (not shown) is provided on the side plate of the printer main body.

  In the process of mounting the photoconductor unit 1Y to the printer main body, the first positioning projection 14Y provided on the left side case 13Y of the photoconductor unit 1Y hits the lower end inner wall of the slit 96Y at the left end in the printer housing. Prior to this, the following phenomenon occurs. That is, the model discriminating protrusion 17Y provided on the left side case 13Y of the photoreceptor unit 1Y engages with the different model unit blocking engaging portion 97Y provided on the left side plate 95 of the printer body. When a photoconductor unit for a printer of a different model from this printer, that is, a photoconductor unit of a different model is to be mounted, some projection of that unit hits the engaging unit 97Y for blocking the different model unit, Unit installation is blocked. As a result, mounting of a different type of photoreceptor unit is avoided. Similarly, the M, C, and K photoconductor units 1M, C, and K can be prevented from mounting different types of units.

  The different-model unit blocking engagement portion 97Y of the left side plate 95 of the printer main body engages with the model discrimination projection 17Y so that the model discrimination projection 17Y of the photoreceptor unit 1Y is allowed to move in the longitudinal direction of the slit 96Y. Match. For this reason, in the photoconductor unit 1Y of an appropriate model, even after the different-model unit blocking engagement portion 97Y that is a movement allowable engagement portion and the model identification protrusion 17Y that is a movement allowable engagement portion start to be engaged. The photosensitive unit 1Y can be further lowered downward and set at a regular set position.

  On the right side plate 98 of the printer main body, a different color unit blocking engagement portion (not shown) is provided next to the entrance of four slits (not shown). The different color unit blocking engaging portion is for Y color discrimination among Y, M, C, K color discrimination projections (not shown) provided in the four photosensitive units 1Y, 1M, 1C, and 1K. Only the protrusions are engaged. Specifically, the four different color unit blocking engaging portions for Y, M, C, and K provided on the right side plate 98 have different shapes. In addition, the Y, M, C, and K color identification protrusions provided on the photosensitive member unit have different shapes. The different color unit blocking engaging portions for Y, M, C, and K are engaged only with the color identifying protrusions having the same corresponding color as the corresponding color.

  In the process of mounting the photoreceptor unit 1Y to the printer main body, the first positioning projection provided on the right side case (not shown) of the photoreceptor unit 1Y hits the lower inner wall of the slit at the right end in the printer housing. The following phenomenon occurs: That is, the color discriminating protrusion provided on the right side case of the photoreceptor unit 1Y engages with the different color unit blocking engaging portion provided on the right side plate 98 of the printer main body. When the photoconductor units 1M, C, and K for M, C, and K, that is, the photoconductor units for different colors are to be mounted, the color discrimination protrusions of the units collide with the different color unit blocking engagement portions. The installation of the unit is prevented. As a result, mounting of the photoreceptor unit in different colors is avoided. Similarly, the M, C, and K photoconductor units 1M, C, and K can be mounted in different colors.

  The different color unit blocking engagement portion of the right side plate 98 of the printer main body engages with the color discrimination projection so as to allow the color discrimination projection of the photosensitive unit 1 to move in the slit longitudinal direction of the right side plate 98. . For this reason, when the appropriate color photosensitive unit is mounted, the different color unit blocking engagement portion that is the movement allowable engagement portion and the color discrimination protrusion that is the movement allowable engagement portion start to engage. Then, the photosensitive member unit can be further lowered and set at a regular setting position.

  As shown in FIG. 7, the IC chip 18Y as an information storage circuit is fixed to the left side case 13Y of the photoreceptor unit 1Y. Also, a plurality of exposed electrodes 19Y that are exposed to the outside while being individually connected to a plurality of input / output terminals (not shown) of the IC chip 18Y are provided. On the other hand, a plurality of contact electrodes (not shown) are provided on the surface of the left side plate (95 in FIG. 8) of the printer body that faces the right side plate (98 in FIG. 8). These contact electrodes have a plurality of exposures of the photoreceptor unit 1Y when the photoreceptor unit 1Y is in a position (normal set position) where the first positioning protrusion 14Y abuts against the inner wall at the lower end of the slit (96Y in FIG. 8). The electrodes 19Y are individually contacted. In this printer, information communication between the IC chip and the control unit (not shown) disposed in the printer housing via the plurality of exposed electrodes 19Y and the plurality of contact electrodes (not shown) that are in contact with each other in this manner. I am trying to do. Then, with respect to a control unit (comprising a CPU, RAM, ROM, etc.) that controls the driving of each color photoconductor unit and transfer unit, the unit ID number, unit operating time, and manufacturing date stored in the IC chip 18Y. Get information such as date. The acquired information is used to determine the life end timing of each color photoconductor unit, and whether it has been replaced or simply attached or detached.

  The above-described different model unit blocking engagement portion 97Y, model discrimination protrusion 17Y, different color unit blocking engagement portion, and color discrimination projection are not provided, but are stored in the IC chip 18Y. Based on the information, it is possible to determine whether or not a different model unit or a different color unit is installed. However, in this case, the determination cannot be performed until the photosensitive unit is pushed into the normal set position and the exposed electrode and the contact electrode are brought into contact with each other. On the other hand, in this printer provided with a movement-permissible engagement portion such as the heterogeneous unit blocking engagement portion 97Y, before the photoreceptor unit is pushed to the proper set position, the installation of the different type unit or the different color unit Wearing can be noticed to the operator. Therefore, it is possible to improve maintenance by omitting useless work by the operator.

  In FIG. 7, the rail-shaped slide guide protrusion 16Y can be regarded as a thick imaginary straight line connecting the first positioning protrusion 14Y and the second positioning protrusion 15Y. In the left case 13Y of the photoconductor unit 1Y, a model discriminating projection 17Y as a movement-permissible engaging portion is provided in one area with the slide guide projection 16Y as a boundary. A plurality of exposed electrodes 19Y are provided in the other region. This is for the reason explained below. That is, if it is attempted to provide the model discrimination projection 17Y and the plurality of exposed electrodes 19Y only in one area with the slide guide projection 16Y as a boundary, the slide guide projection is provided due to the installation space in the unit thickness direction. It is necessary to widen the set space by shifting the arrangement position of the portion 16Y from the illustrated state to one end side or the other end side in the unit thickness direction. If it does so, it will necessarily be necessary to shift the 1st positioning protrusion 14Y and the 2nd positioning protrusion 15Y similarly. That is, it is necessary to dispose both positioning protrusions so as to be biased toward the end side in the unit thickness direction. In such a configuration, the photosensitive unit 1Y is supported by the first positioning protrusions 14Y and the second positioning protrusions 15Y disposed at the biased positions, so that the balance is deteriorated and rattling during operation is likely to occur. On the other hand, in this printer, the model determining projection 17Y and the plurality of exposed electrodes 19Y are separately arranged on both sides of the slide guide projection 16Y as a boundary, so that the first positioning projection 14Y. And the second positioning projection 15Y can be disposed at substantially the center in the unit thickness direction. Therefore, the photosensitive unit 1Y can be supported in a well-balanced manner, and the occurrence of rattling of the unit during operation can be suppressed.

  In the photoconductor unit 1Y of this printer, as shown in the drawing, the plurality of exposed electrodes 19Y are arranged side by side in the unit thickness direction substantially perpendicular to the extending direction of the slide guide protrusion 16Y (agreeing with the longitudinal direction of the slit 96Y). Has been established. Also on the left side plate (95 in FIG. 8) of the printer main body, a plurality of contact electrodes (not shown) are arranged in the unit thickness direction. This is for the reason described below. That is, in the process of mounting the photoconductor unit in which the plurality of exposed electrodes 19Y are arranged in the extending direction of the slide guide protrusion 16Y on the image forming apparatus main body, the plurality of exposed electrodes do not correspond to themselves. In the case of contact corresponding to itself without contacting, it is necessary to arrange a plurality of contact electrodes (not shown) on the left side plate of the printer main body side by side so as to correspond to them. In such a layout, in the process of mounting the photosensitive unit 1Y in the housing of the printer main body, for example, among the plurality of exposed electrodes 19Y provided on the photosensitive unit 1Y, the lowermost exposed electrode 19Y is set to the left side. By moving to the contact position with the lowermost contact electrode on the plate, all the other contact electrodes are rubbed. Further, in the left side plate, all the exposed electrodes 19Y that normally do not need to be contacted are rubbed against the uppermost contact electrode. As a result, the amount of wear of the contact electrode due to repeated attachment / detachment operation of the photoreceptor unit 1Y is increased, and contact failure between the exposed electrode 19Y and the contact electrode is likely to occur. On the other hand, in this printer, the plurality of exposed electrodes 19Y and the plurality of contact electrodes are arranged in the unit thickness direction, so that the plurality of exposed electrodes 19Y are not in contact with contact electrodes that do not correspond to each other, respectively. Move to the contact position with the corresponding contact electrode. Therefore, the occurrence of contact failure due to wear of the contact electrode can be suppressed.

  In the left side case 13Y of the photoreceptor unit 1Y, an area (in this example, an exposed electrode) that slidably contacts a contact electrode (not shown) of the printer body in the process of mounting the photoreceptor unit 1Y to the printer body, out of the entire planar area. The protective sheet 20 is fixed to a region below 19Y. The protective sheet 20 is made of PET (polyethylene terephthalate) having a smaller friction coefficient than the solid surface of the left side case 13Y. That is, the photosensitive unit 1Y is subjected to a low friction process on an area that slides on the contact electrode of the printer main body (left side plate 95) in the process of being mounted on the printer main body. Accordingly, it is possible to avoid the left side case 13Y from being damaged by directly rubbing the contact electrode of the printer main body and the solid surface of the left side case 13Y.

  In this printer, a plurality of contact electrodes provided on the left side plate (95) of the printer main body are each extended in the longitudinal direction of the slit (96Y) of the left side plate. This is for the reason explained below. That is, the photoconductor unit 1Y is provided with a drive receiving gear (not shown) (photosensitive gear fixed to the photoconductor shaft in this example), and meshes with a driving side gear on the printer main body side, thereby the printer main body. Drive is transmitted into the unit from the side. In this configuration, when the photosensitive unit 1Y is pushed into the printer main body, if the rotational posture relationship between the drive receiving gear of the unit and the driving gear on the main body side is inappropriate, the gear tips of both gears are There is a case where the unit is not set correctly at the normal position by abutting (a state where the first positioning projection 14Y does not abut against the inner wall of the lower end of the slit 96Y. Hereinafter, referred to as “subtle misalignment of the set position due to the gear abutment”). Even if such a slight misalignment of the set position occurs, if the driving side gear starts to rotate and the gears are properly meshed with each other, the photosensitive unit 1Y moves downward due to its own weight, and the normal gear Set to position naturally. However, there is a possibility that contact failure occurs between the exposed electrode 19Y of the unit and the contact electrode of the left side plate (95) due to the positional deviation in the slit longitudinal direction until it is set to the normal position. Therefore, in this printer, by extending the contact electrode in the slit longitudinal direction, the exposed electrode 19Y and the contact electrode are reliably brought into contact with each other even when a slight set position shift occurs due to the contact of the gear. Instead of extending the contact electrode in the slit longitudinal direction, the exposed electrode 19Y may be extended in the slit longitudinal direction.

  FIG. 9 is a left side view showing the Y photoconductor unit 1Y. In the figure, for the purpose of partially showing the inside of the left side case 13Y, the illustration of the case region directly under the IC chip 18Y is omitted. In the figure, the imaginary line segment L1 extends in the vertical direction. Further, the imaginary line segment L2 connects the cylindrical center of the first positioning projection 14Y and the cylindrical center of the second positioning projection 15Y, and the extending direction thereof is a slit (not shown) on the left side plate of the printer main body (not shown). 8 along the longitudinal direction of 96Y).

  In this printer, as indicated by the imaginary line segment L2 in the figure, the longitudinal direction of the slit (not shown) is shifted from the vertical direction (the extending direction of the imaginary line segment L1). This is for the reason explained below. That is, when the longitudinal direction of the slit is along the vertical direction, it becomes a one-point support for supporting almost the entire weight of the photoreceptor unit 1Y by the first positioning protrusion 14Y, and the balance becomes unstable. On the other hand, in order to smoothly slide the first positioning protrusion 14Y and the second positioning protrusion 15Y within the slit, it is necessary to provide a certain amount of clearance between the positioning protrusion and the inner wall of the slit. If it does so, it will become easy to rattle the photoconductor unit 1Y which is poorly balanced by supporting one point in the slit width direction within the range of the clearance. On the other hand, when the slit longitudinal direction (L2 extending direction) is shifted from the vertical direction (L1 extending direction) as in this printer, the photoreceptor unit 1Y is moved to the first positioning protrusion 14Y and the second positioning protrusion 15Y. Since the two-point support will be performed with both, the unit can be supported with a stable balance. As a result, the backlash in the slit width direction of the photoreceptor unit 1Y can be suppressed.

  In the figure, the lower end of the first positioning protrusion 14Y is a contact point with the inner wall of the lower end of a slit (not shown). With respect to the photoreceptor unit 1Y, the contact point described above is caused by a reaction such as meshing between the photoreceptor gear 21Y and the developing roller gear 22Y in the interior and meshing between the photoreceptor gear 21Y and a driving gear (not shown) on the printer main body side. A force is applied to rotate the photosensitive unit 1Y in the clockwise direction or the counterclockwise direction with respect to. In this printer, a force acts to rotate the photosensitive unit clockwise in the figure with the above-mentioned contact point as a fulcrum. In the printer, as shown in the figure, the layout is such that the virtual line segment L2 is tilted clockwise with respect to the virtual line segment L1. This is for the reason explained below. That is, when the imaginary line segment L2 is tilted in the same direction as the rotation direction due to the meshing of the gears, the second positioning protrusion 14Y of the photoreceptor unit 1Y opposes in the width direction within a slit (96Y in FIG. 8). Of the two inner walls of the slit, the inner wall is supported while being in contact with the inner wall of the slit located on the rotation direction side. Then, even if a force in the above-described rotation direction acts on the photosensitive unit 1Y, the second positioning protrusion 14Y does not rattle toward the opposite slit inner wall in the slit, and the force Is received by the inner wall of the slit located on the side in the rotational direction. Thereby, it is possible to avoid rattling of the photoreceptor unit 1Y due to the reaction of the meshing of the gears.

  Up to now, a drum cleaning device 3K, a static eliminator (not shown), a charging device 4K, and a developing device 5K as members disposed around the photoconductor 2Y are held in a unit casing together with the photoconductor 2Y. However, only one to three of these members may be held in the unit casing. Alternatively, a photoreceptor unit 1Y in which members different from those members are held in the unit casing together with the photoreceptor 2Y may be employed.

  As described above, in the printer, as the photosensitive unit 1Y, the slide guide protrusion 16Y, which is an extending protrusion extending in the longitudinal direction of the slit 96Y, is connected to the first positioning protrusion 14Y and the second positioning protrusion 15Y. The slide guide projection 16Y is also provided between the first positioning projection 14Y and the second positioning projection 15Y and the same slit 96Y. In such a configuration, as described above, the second positioning protrusion 15Y is smoothly guided toward the entrance of the slit 96Y by the sliding movement of the slide guide protrusion 16Y in the slit 96Y, so that the photoconductor unit 1Y can move. Setability can be improved.

  Further, in this printer, the photosensitive unit 1Y uses the first positioning projection 14Y made of a metal material and the second positioning projection 15Y made of a resin material. This is for the reason explained below. In other words, the first positioning protrusion 14Y plays a role of blocking the further pressing operation by abutting against the inner wall of the lower end of the slit while the photosensitive unit 1Y is being pressed into the printer body. This gives a considerable impact. If the rigidity that can withstand this impact is not exhibited, the desired positioning accuracy cannot be obtained due to the deformation or breakage of the protrusion during the impact. For this reason, about the 1st positioning protrusion 14Y, it forms with the metal material which is highly rigid. On the other hand, since the second positioning protrusion 15Y does not give much impact, it is formed of the same resin material as that of the unit casing, thereby simplifying the manufacturing process by integrally forming the unit casing. .

  Further, in this printer, apart from the combination of the first positioning protrusion 14Y and the second positioning protrusion 15Y and the slit 96Y, they are engaged with each other so as to allow movement of the photosensitive unit 1Y in the slit longitudinal direction. The movement allowing engagement portion is provided in the photoconductor unit 1Y and the printer main body. More specifically, a model discriminating protrusion 17Y as a movement-permissible engaging portion and a color discriminating protrusion are provided on the photosensitive unit 1Y, and a different-model unit blocking engagement as a movement-permissible engaging portion that engages with each of them. The portion 97Y and the different color unit blocking engagement portion are provided on the side plate of the printer main body. In the process of mounting the photoreceptor unit 1Y to the printer main body, before the first positioning projection 14Y is abutted against the inner wall of the lower end of the slit, which is the abutted portion, the model discrimination projection 17Y of the photoreceptor unit 1Y, the color discrimination The projecting portion is engaged with the engaging unit 97Y for blocking different types of units and the engaging unit for blocking different color units on the side plate of the printer main body. In this configuration, as described above, it is possible to avoid erroneous mounting of a different-type photoconductor unit or wrong mounting of a different-color photoconductor unit.

  Further, in the present printer, a plurality of combinations of the movement-permissible engaging portions are provided on the photoconductor unit 1Y and the side plate of the printer main body. It is possible to avoid both erroneous mounting.

  Further, in this printer, the IC chip 18Y as an information storage circuit storing unit ID number, unit operating time, date of manufacture, etc. as predetermined information, and exposure exposed to the outside while being connected to the IC chip 18Y. The electrode 19Y is provided on the photoconductor unit 1Y, and the photoconductor unit 1Y is exposed when the photoconductor unit 1Y is in a position where the first positioning protrusion 14Y of the photoconductor unit 1Y abuts against the inner wall of the lower end of the slit as the abutting portion of the printer body. A contact electrode that contacts the electrode 19 is provided on the printer body. Information communication is performed between the IC chip 18Y and the control unit, which is a control unit disposed in the printer body, via the exposed electrode 19Y and the contact electrode that are in contact with each other. In such a configuration, as described above, by reading the information unique to each unit product such as the unit ID number, unit operating time, manufacturing date, etc. from the chip or writing to the chip, For each color photoconductor unit, it is possible to determine the life end timing, or to determine whether it has been replaced or simply attached or detached.

  Further, in this printer, as the photosensitive unit 1Y, a model identification projection that is a movement-permissible engagement portion in one area with a virtual straight line connecting the first positioning projection 14Y and the second positioning projection 15Y as a boundary. 17Y is provided, and the other region is provided with the exposed electrode 19Y. In such a configuration, as described above, the first positioning protrusion 14Y and the second positioning protrusion 15Y are arranged at substantially the center in the unit thickness direction so as to support the photosensitive unit 1Y in a balanced manner. Occurrence of rattling of the unit during operation can be suppressed.

  In the printer, the photosensitive unit 1Y has a low area in the entire area of the surface of the left side case 13Y, which is the surface of the casing, in an area that rubs with the contact electrode of the printer body during the process of being mounted on the printer body. The one that has been subjected to friction treatment is used. In this configuration, as described above, it is possible to avoid the left side case 13Y from being damaged by directly rubbing the contact electrode of the printer main body and the solid surface of the left side case 13Y.

  Further, in this printer, as a layout of a combination of a plurality of exposed electrodes 19Y and a plurality of contact electrodes individually corresponding to each exposed electrode 19Y, a plurality of a plurality of exposed electrodes 19Y are mounted in the process of mounting the photoreceptor unit 1Y on the printer body. A layout is adopted in which the exposed electrode 19Y is moved to the contact position with the contact electrode corresponding to itself without contacting the contact electrode not corresponding to itself. In this configuration, as described above, it is possible to avoid the occurrence of contact failure between the two electrodes due to the contact electrode being unnecessarily rubbed and worn with the exposed electrode 19Y.

  Further, in the present printer, at least one of the exposed electrode 19Y and the contact electrode is one that extends in the slit longitudinal direction. In such a configuration, as described above, even if a slight set position deviation due to a gear hit occurs, information is read from the IC chip 18Y by reliably bringing the exposed electrode 19Y into contact with the contact electrode in that state. Can be made.

  In this printer, the longitudinal direction of the slit is shifted from the vertical direction. In this configuration, as described above, the photosensitive member unit 1Y is supported by the two-point support system that supports both the first positioning protrusion 14Y and the second positioning protrusion 15Y, thereby supporting the unit in a stable balance. The backlash in the slit width direction of the body unit 1Y can be suppressed.

  Further, in this printer, due to the rotational moment of the drive transmission gear (photosensitive gear 21Y and developing roller gear 22Y) in the photosensitive unit 1Y and the rotational moment of the drive transmission gear between the photosensitive unit 1Y and the printer main body, The longitudinal direction of the slit is inclined with respect to the vertical direction toward the rotational direction of the rotational force applied to the photoreceptor unit 1Y with the contact point between the first positioning protrusion 14Y and the inner wall at the lower end of the slit as a fulcrum. In such a configuration, as described above, the second positioning protrusion 14Y is not rattled in the slit 96Y, and the rotational moment is received by the slit inner wall located on the side in the rotational direction as it is. It is possible to avoid rattling of the photoreceptor unit 1Y due to the reaction of the gear meshing.

1Y, M, C, K: Photosensitive unit (latent image carrier unit)
2Y, M, C, K: photoconductor (latent image carrier)
5K: developing device (developing means)
14Y: First positioning protrusion 15Y: Second positioning protrusion 16Y: Slide guide protrusion (extending protrusion)
17Y: Protrusion for model discrimination (movement allowable engagement part)
18Y: IC chip (information storage circuit)
19Y: Exposed electrode 20Y: Protective sheet (low friction treatment)
90: Optical writing unit (latent image writing means)
95: Left side plate (one of two opposing members)
96Y: Slit 97Y: Engagement part for blocking different types of units (movable engagement part)
98: Right side plate (the other of the two opposing members)

JP 2002-108173 A

Claims (10)

A latent image carrier unit having a latent image carrier on the surface and detachable from the main body of the image forming apparatus; latent image writing means for writing a latent image on the surface; and the latent image Developing means for developing with toner,
The latent image carrier unit has first positioning protrusions that engage with grooves or slits respectively provided on two opposing surfaces of the image forming apparatus main body,
The groove or the slit has an abutted portion that abuts against the first positioning projection,
When the latent image carrier unit is attached to the main body of the image forming apparatus, the abutting portion and the first positioning protrusion abut against each other, so that the main body of the image forming apparatus of the latent image carrier unit. In the image forming apparatus in which positioning in the attaching / detaching direction with respect to the image forming apparatus main body is performed,
An information storage circuit that stores predetermined information, an exposed electrode that is exposed to the outside while being connected to the information storage circuit, and the first positioning protrusion are located at positions shifted in the attachment / detachment direction. A second positioning projection for positioning the carrier unit is provided on the latent image carrier unit;
When the latent image carrier unit is mounted on the image forming apparatus main body, the second positioning protrusion is connected to the groove or the slit to be engaged with the first positioning protrusion. Is engaged with the position shifted in the attaching / detaching direction,
A contact electrode in contact with the exposed electrode of the latent image carrier unit in a state where the first positioning protrusion is in contact with the abutted portion of the image forming apparatus body in the image forming apparatus body Is provided in the image forming apparatus main body,
Via the exposed electrode and the contact electrode that are in contact with each other, control means disposed in the image forming apparatus main body and information communication with the information storage circuit are performed ,
The combination of the first positioning protrusion and the second positioning protrusion and the groove or the slit on at least one of the two side faces of the latent image carrier unit corresponding to the two faces. Separately, a movement permissible engaging portion that engages with each other so as to allow the movement of the latent image carrier unit in the attaching / detaching direction is provided in each of the latent image carrier unit and the image forming apparatus main body,
As the latent image carrier unit, at least one of the two side surfaces has the movement-permissible engagement in one region with a virtual straight line connecting the first positioning projection and the second positioning projection as a boundary. An image forming apparatus using the one provided with the exposure electrode in the other region . The image forming apparatus according to claim 1 .
The latent image bearing member unit in the process of mounting to the image forming apparatus main body, the first positioning projection before abutting on the abutted portion, movement permitting engagement portion of the latent image bearing member unit and the An image forming apparatus characterized in that a movement allowable engaging portion of an image forming apparatus main body is engaged. The image forming apparatus according to claim 2.
An image forming apparatus, wherein each of the two side surfaces of the latent image carrier unit is provided with a plurality of combinations of the movement-permissible engaging portions in the latent image carrier unit and the image forming apparatus main body . The image forming apparatus according to any one of claims 1 to 3 ,
As the latent image carrier unit, a low-friction process was performed on an area of the entire surface of the unit housing that rubs against the contact electrode of the image forming apparatus main body in the process of being attached to the image forming apparatus main body. An image forming apparatus using the apparatus. The image forming apparatus according to any one of claims 1 to 4 ,
An image forming apparatus comprising a plurality of combinations of the exposed electrode and the contact electrode in the latent image carrier unit and the image forming apparatus main body. The image forming apparatus according to claim 5 .
As a layout of a combination of a plurality of the exposed electrodes and a plurality of the contact electrodes individually corresponding to the exposed electrodes, a plurality of exposed in the process of mounting the latent image carrier unit on the image forming apparatus main body. An image forming apparatus characterized by adopting a layout in which an electrode is moved to a contact position with a contact electrode corresponding to itself without contacting the electrode with a contact electrode not corresponding to itself. The image forming apparatus according to claim 1 to 6,
An image forming apparatus using at least one of the exposed electrode and the contact electrode that extends in the attaching / detaching direction. The image forming apparatus according to claim 1 to 7,
An image forming apparatus, wherein the attaching / detaching direction is shifted from a vertical direction. The image forming apparatus according to claim 8 .
Due to the rotational moment of the drive transmission gear in the latent image carrier unit and the rotational moment of the drive transmission gear between the latent image carrier unit and the image forming apparatus main body, the first positioning projection and the projected object An image forming apparatus characterized in that the attaching / detaching direction is inclined with respect to the vertical direction toward the rotational direction side of the rotational force applied to the latent image carrier unit with a contact point with the contact portion as a fulcrum. . The image forming apparatus according to claim 1 to 9,
The latent image carrier is a member that is rotatably supported around a shaft member, and the first positioning projection is provided at an end of the shaft member in the axial direction. Equipment .

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