JP4654630B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  In an image forming apparatus using a known electrophotographic process, an image forming apparatus including an image forming unit including a photosensitive drum, an intermediate transfer belt, etc. (image carrier) is detachable from the image forming apparatus main body. There is. Then, when various parts of the image forming unit reach the end of their service life, replacement with a new image forming unit facilitates maintenance. (For example, refer to the prior document 1).

  In the image forming unit, a part of the photosensitive drum and the intermediate transfer belt is exposed from the image forming unit for transfer and development. For this reason, the new image forming unit needs to protect the exposed portion of the photosensitive drum and the intermediate transfer belt for dust prevention and scratch prevention, and the image forming unit opens when the image forming unit is mounted on the image forming apparatus main body. The exposed portion is protected by a cover or a protective paper that is removed before mounting a new image forming unit on the image forming apparatus main body (see, for example, Patent Document 2).

Also, in such an image forming apparatus, detection for detecting whether or not the mounted image forming unit is new or whether or not a protective member such as protective paper has been removed is detected. Means. Providing such detection means is expensive.
JP 2001-56592 A JP-A-8-272281

  It is an object to detect at low cost whether or not the mounted image forming unit is new.

The image forming apparatus according to claim 1, wherein the image forming unit includes at least a rotating image carrier on which a toner image is formed, and is attachable to and detachable from the main body of the image forming apparatus. A mark that can be exposed from the unit, and a detection unit that is provided in the image forming apparatus main body and that detects the mark exposed from the image forming unit, and the mark of the unused image forming unit includes the mark When the image forming unit is mounted on the main body of the image forming apparatus, the detection unit becomes a position that can be detected, and when the image forming unit is used, the image carrier rotates and the mark is not detected by the detection unit. The image carrier is stopped so as to be in a position, and the mark also serves as a reference mark serving as a reference position when a toner image is formed on the image carrier.

  In the image forming apparatus according to the first aspect, a mark that can be exposed from the image forming unit is provided on the image carrier. The image forming apparatus main body includes a detection unit that detects a mark exposed from the image forming unit. Then, the mark on the image carrier of the unused image forming unit is in a position that can be detected by the detection unit when the image forming unit is mounted on the main body of the image forming apparatus.

  Accordingly, when the image forming unit is mounted and the detection unit detects the mark, it is found that the image forming unit is unused, that is, a new image forming unit.

  When the image forming unit is used, the image carrier rotates, and the mark deviates from a position that can be detected by the detection unit. Therefore, even if the used image forming unit is taken out from the main body of the image forming apparatus and then mounted again, the detection unit does not detect the mark, so it is not recognized as a new product.

  Thus, it is possible to detect whether or not the image forming unit is new with a simple and inexpensive configuration.

The mark referred to here means a mark for the image carrier, and includes, for example, any of those attached to the image carrier, those applied, and holes formed in the image carrier. .
Further, since the mark also serves as a reference mark serving as a reference position when a toner image is formed on the image carrier, the cost is lower.

  According to a second aspect of the present invention, in the configuration according to the first aspect, the image forming unit includes an exposed portion where the image carrier is exposed from the image forming unit, and the exposed mark. A protective member that covers and is removable from the image forming unit is attached.

In the image forming apparatus of the second aspect, the unused image forming unit is provided with a protective member that covers the exposed portion where the image carrier is exposed from the image forming unit and the exposed mark. Since the image cannot be formed if the protective member remains attached, it is necessary to remove the protective member.

  If the protective member is still attached to the image forming unit, the detection unit does not detect the mark, so that it can be seen that the protective member has not been removed. That is, it is possible to detect whether or not the protective member is removed from the image forming unit with a simple and inexpensive configuration. Further, it can be determined whether or not it is a new article by whether or not the protective member is removed.

  According to a third aspect of the present invention, in the configuration according to the second aspect, the detection unit can detect the mark and the protective member separately.

  In the image forming apparatus according to the third aspect, the detection unit can detect the mark and the protection member separately. Therefore, when the image forming unit is mounted on the image forming apparatus and the detection unit detects the protection member, it is understood that the protection member has not been removed. Further, when the detection unit detects the mark, the protective member is removed, and it is found that the image forming unit is a new image forming unit.

Therefore, it is possible to detect both whether or not the image forming unit is new and whether or not the protective member is removed with a simple and inexpensive configuration.
5. The image forming apparatus according to claim 4, wherein the image forming unit includes at least a rotating image carrier on which a toner image is formed and is detachable from the main body of the image forming apparatus, and the image carrier. A mark that can be exposed from the unit, and a detection unit that is provided in the image forming apparatus main body and that detects the mark exposed from the image forming unit, and the mark of the unused image forming unit includes the mark When the image forming unit is mounted on the main body of the image forming apparatus, the detection unit becomes a position that can be detected, and when the image forming unit is used, the image carrier rotates and the mark is not detected by the detection unit. the image bearing member such that the position stops, the mark is the image forming unit unused and exposed portions of the image bearing member from said image forming unit is exposed, the exposed Covers, removable protective member is attached from said imaging unit, the detection unit is characterized in that it is detectable by distinguishing between the protective member and the mark.
In the image forming apparatus according to the fourth aspect, it is understood that the protective member is not removed because the detection unit does not detect the mark if the protective member is still attached to the image forming unit. That is, it is possible to detect whether or not the protective member is removed from the image forming unit with a simple and inexpensive configuration. Further, it can be determined whether or not it is a new article by whether or not the protective member is removed.
Moreover, the detection part can detect and distinguish a mark and a protection member. Therefore, when the image forming unit is mounted on the image forming apparatus and the detection unit detects the protection member, it is understood that the protection member has not been removed. Further, when the detection unit detects the mark, the protective member is removed, and it is found that the image forming unit is a new image forming unit.
According to a fifth aspect of the present invention, in the configuration according to the fourth aspect, the mark also serves as a reference mark serving as a reference position when a toner image is formed on the image carrier.
In the image forming apparatus according to the fifth aspect, since the mark also serves as a reference mark serving as a reference position when a toner image is formed on the image carrier, the cost is lower.

The image forming apparatus according to claim 6 is the configuration according to any one of claims 2 to 5 , wherein the protection member is a sheet-like protection sheet, and the image forming unit includes the image forming unit. And a protective sheet supporting means for supporting the protective sheet so that the protective sheet can be removed from between the image forming unit and the image forming apparatus main body after being mounted on the forming apparatus main body.

In the image forming apparatus according to claim 6, the protective sheet can be removed from between the image forming unit and the image forming apparatus main body after the image forming unit is attached to the main body of the image forming apparatus by the protective sheet supporting unit. It is supported by. For this reason, the image forming unit can be attached to the image forming apparatus main body with the protective sheet attached. For example, the hand touches the exposed part of the image carrier or the exposed part of the image carrier is the image forming apparatus main body. It can be prevented from being damaged by hitting.

According to a seventh aspect of the present invention, in the configuration according to any one of the first to sixth aspects, the image forming unit includes a housing in which an exposure window through which the mark can be exposed is formed. The detection unit detects the mark exposed from the exposure window, and the mark of the unused image forming unit is exposed from the exposure window.

In the image forming apparatus according to the seventh aspect, the mark of the unused image forming unit is exposed from the exposure window, so that the detection unit can detect the position. Therefore, mark alignment is easy.

  As described above, according to the present invention, it is possible to detect whether or not the mounted image forming unit is new at low cost.

  Next, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an image forming apparatus main body 12, and an opening / closing cover 16 that is rotatable about a rotation fulcrum 14 is provided on the upper portion of the image forming apparatus main body 12. For example, a one-stage sheet feeding unit 18 is disposed at a lower portion of the sheet 12.

  The paper feed unit 18 includes a paper feed unit main body 20 and a paper feed cassette 22 in which paper is stored. A feed roll 24 that feeds paper from the paper feed cassette 22 and a retard roll 26 that sprinkles the fed paper one by one are arranged in the upper vicinity of the rear end of the paper feed cassette 22.

  The conveyance path 28 is a sheet path from the feed roll 24 to the discharge port 30, and this conveyance path 28 is in the vicinity of the back side (right side in FIG. 1) of the image forming apparatus main body 12 and will be described later from the sheet feeding unit 18. The fixing device 90 is formed substantially vertically. A secondary transfer roll 80 and a secondary transfer backup roll 72, which will be described later, are arranged on the upstream side of the fixing device 90 in the conveyance path 28, and the registration roll 32 is located upstream of the secondary transfer roll 80 and the secondary transfer backup roll 72. Is arranged. In addition, a discharge roll 34 is disposed in the vicinity of the discharge port 30 of the conveyance path 28.

  That is, the sheet fed from the sheet feeding cassette 22 of the sheet feeding unit 18 by the feed roll 24 is turned by the retard roll 26 and only the uppermost sheet is guided to the transport path 28 and stopped by the registration roll 32. The toner image is transferred between a secondary transfer roll 80 and a secondary transfer backup roll 72, which will be described later, at a timing. The sheet is fixed on the transferred toner image by the fixing device 90, and is discharged from the discharge port 30 to the discharge portion 36 provided on the upper portion of the opening / closing cover 16 by the discharge roll 34. The discharge portion 36 has a low discharge port portion and is inclined so as to gradually increase toward the front direction (left direction in FIG. 1).

  In the image forming apparatus main body 12, for example, a rotary developing device 38 is disposed at a substantially central portion. The rotary developing device 38 includes developing units 42a to 42d that respectively form toner images of four colors of yellow, yellow, magenta, cyan, and black in the developing unit main body 40. It rotates counterclockwise (counterclockwise in FIG. 1) about the rotary developing device center 44. Each of the developing units 42a to 42d has developing rolls 46a to 46d, and is pressed in the normal direction of the developing unit main body 40 by elastic bodies 48a to 48d such as coil springs.

  The rotary developing device 38 is arranged so as to rotate, for example, around the rotation support shaft 49 so that the photosensitive member 50 comes into contact therewith, and the developing rolls 46a to 46d are not in contact with the photosensitive member 50, respectively. A part of the outer periphery of the developing device protrudes from the outer periphery of the developing device main body 40 in the radial direction, for example, 2 mm. Further, a tracking roll (not shown) having a diameter slightly larger than the diameter of the developing rolls 46a to 46d is provided at both ends of each of the developing rolls 46a to 46d so as to rotate coaxially with the developing rolls 46a to 46d. Yes. That is, the developing rolls 46a to 46d of the developing units 42a to 42d are arranged on the outer periphery of the developing unit main body 40 with an interval of 90 ° around the rotary developing device center 44, and the tracking rolls of the developing rolls 46a to 46d are photosensitive. The latent images on the photoconductor 50 are in contact with flanges (not shown) provided at both ends of the photoconductor 50, and a predetermined gap is formed between the developing rolls 46a to 46d and the photoconductor 50. Develop with toner.

  Below the photoconductor 50, a charging device 52 made of, for example, a charging roll, for uniformly charging the photoconductor 50 is provided. In addition, a photoreceptor cleaner 54 is held on the photoreceptor 50 so as to hang from the rotation support shaft 49, and the photoreceptor 50 and the photoreceptor cleaner 54 are integrated. The photoreceptor cleaner 54 includes, for example, a cleaning blade 56 that scrapes waste toner remaining on the photoreceptor 50 after primary transfer, and a toner collection bottle 58 that collects waste toner scraped by the cleaning blade 56.

  The back side (right side in FIG. 1) of the toner collection bottle 58 is formed with a rib or the like, for example, and is curved to form a part of the conveyance path 28 so that the paper is smoothly conveyed.

  On the lower back side of the rotary developing device 38, an exposure device 60 for writing a latent image on the photosensitive member 50 charged by the charging device 52 with a light beam such as a laser beam is disposed. Further, an intermediate transfer device 62 is provided above the rotary developing device 38. The toner image visualized by the rotary developing device 38 is primarily transferred at the primary transfer position and conveyed to a secondary transfer position described later.

  The intermediate transfer device 62 includes an intermediate transfer member 64 such as an intermediate transfer belt, a primary transfer roll 66, a wrap-in roll 68, a wrap-out roll 70, a secondary transfer backup roll 72, a scraper backup roll 74, and a brush backup roll 76. .

  The intermediate transfer body 64 has elasticity, for example, and is stretched substantially flat so as to have a long side and a short side above the rotary developing device 38. The long side on the upper surface side of the intermediate transfer body 64 is stretched so as to be substantially parallel to, for example, the discharge unit 36 provided on the upper portion of the image forming apparatus main body 12.

  The intermediate transfer member 64 includes a wrap-in roll 68 disposed upstream of the primary transfer roll 66 below the long side of the intermediate transfer member 64, and a wrap-out roll 70 disposed downstream of the primary transfer roll 66. A primary transfer portion (photoconductor wrap region) that contacts the photoconductor 50 in a wrap-like manner is provided. The photoconductor 50 is wound around the photoconductor 50 by a predetermined range and is driven by the rotation of the photoconductor 50.

  In this way, the intermediate transfer body 64 is primarily transferred by the primary transfer roll 66 while superimposing the toner images on the photoreceptor 50 in the order of yellow, magenta, cyan, and black, for example. It is conveyed toward the next transfer roll 80. Note that the wrap-in roll 68 and the wrap-out roll 70 are separated from the photoconductor 50.

  Thus, the intermediate transfer body 64 is stretched by five rolls of the wrap-in roll 68, the wrap-out roll 70, the secondary transfer backup roll 72, the scraper backup roll 74, and the brush backup roll 76, and the primary transfer roll 66, the toner image on the photoconductor 50 is transferred.

  Further, a flat surface portion (short side) is formed on the back side (right side surface in FIG. 1) of the intermediate transfer body 64 by a wrap-out roll 70 and a secondary transfer backup roll 72, and this flat surface portion is subjected to secondary transfer. It faces the conveyance path 28 as a part.

  In the secondary transfer portion, the wrap-out roll 70 is arranged so that the intermediate transfer body 64 and the conveyance path 28 are at an angle of 12 °, for example.

  The scraper backup roll 74 assists the scraper 84 described later to scrape waste toner remaining on the intermediate transfer body 64 after the secondary transfer, and the brush backup roll 76 wastes remaining on the intermediate transfer body 64 after the secondary transfer. The brush roll 86 described later assists in scraping off the toner.

  A secondary transfer roll 80 is opposed to the secondary transfer backup roll 72 of the intermediate transfer device 62 with the conveyance path 28 interposed therebetween. That is, the secondary transfer position in the secondary transfer portion is between the secondary transfer roll 80 and the secondary transfer backup roll 72, and the secondary transfer roll 80 is intermediate with the assistance of the secondary transfer backup roll 72. The toner image primarily transferred to the transfer body 64 is secondarily transferred onto the paper at the secondary transfer position.

  Here, the secondary transfer roll 80 is separated from the intermediate transfer body 64 while the intermediate transfer body 64 rotates three times, that is, while the toner images of three colors of yellow, magenta, and cyan are transported. When the image is transferred, it comes into contact with the intermediate transfer member 64.

  In addition, a predetermined potential difference is generated between the secondary transfer roll 80 and the secondary transfer backup roll 72. For example, when the secondary transfer roll 80 is set to a high voltage, the secondary transfer backup 80 The roll 72 is connected to a ground (GND) or the like.

  An intermediate transfer body cleaner 82 is provided at the end of the intermediate transfer body 64 opposite to the photoconductor. The intermediate transfer body cleaner 82 includes a scraper 84, a brush roll 86, a toner collection bottle 88, and a rotation support shaft 89, and swings about the rotation support shaft 89. For example, the scraper 84 scrapes off and cleans waste toner remaining on the intermediate transfer member 64 after the secondary transfer. The brush roll 86 further scrapes off the waste toner remaining after cleaning by the scraper 84. The toner collection bottle 88 collects the toner scraped by the scraper 84 and the brush roll 86. The scraper 84 is made of, for example, a thin plate made of stainless steel, and is applied with a voltage having a polarity opposite to that of the toner.

  The brush roll 86 is made of, for example, an acrylic brush that has been subjected to a conductive treatment. While the intermediate transfer member 64 conveys the toner image, the scraper 84 and the brush roll 86 are separated from the intermediate transfer member 64 and come into contact with the intermediate transfer member 64 at a predetermined timing. Has been.

  The intermediate transfer device 62, the photosensitive member 50, the charging device 52, the photosensitive member cleaner 54, and the intermediate transfer member cleaner 82 are integrated to form a part of an image forming unit 96 described later.

  A fixing device 90 is disposed above the secondary transfer position. The fixing device 90 includes a heating roll 92 and a pressure roll 94, fixes the toner image secondarily transferred to the sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72, and fixes the toner image to the discharge roll 34. Transport toward.

  As shown in FIG. 1, an operation panel 210 for performing various operations by the user and displaying various information to the user is provided at the upper part of the back side (right side in FIG. 1) of the image forming apparatus main body 12. . Further, on the front side (left side in FIG. 1) of the rotary developing device 38 of the image forming apparatus main body 12, the image forming apparatus includes control of each functional component of the image forming apparatus main body 12 and display of various information on the operation panel 210. A control unit 109 that controls the entire 10 is provided.

  The details of the image forming unit 96 are shown in FIGS.

  The image forming unit 96 includes a pair of side frames 100a and 100b provided on the left and right (left and right in FIG. 4), and a pair of protective covers 102a and 102b provided on the top and bottom (up and down in FIG. 3). 99, the intermediate transfer device 62, the photosensitive member 50, the charging device 52, the photosensitive member cleaner 54, and the intermediate transfer member cleaner 82 are integrated. Further, the side frames 100a and 100b, the protective covers 102a and 102b, the intermediate transfer device 62, and the intermediate transfer body cleaner 82 are integrated to form an intermediate transfer body assembly 97. The photoconductor 50, the charging device 52 and the photoconductor cleaner 54 are integrated to form a photoconductor unit 98. That is, as shown in FIG. 3, the image forming unit 96 is formed by assembling the photoconductor unit 98 to the intermediate transfer body assembly 97 via a bearing 111 and a bearing 132 described later. The photoreceptor unit 98 is detachably attached to the intermediate transfer body assembly 97, and the intermediate transfer body assembly 97 has a predetermined tension applied to the intermediate transfer body 64 when the photoreceptor unit 98 is mounted. And a primary transfer portion is formed between the photosensitive member 50 and the photosensitive member 50.

  The intermediate transfer body 64 is supported so as to be rotated by five rolls of a secondary transfer backup roll 72, a wrap-in roll 68, a wrap-out roll 70, a scraper backup roll 74, and a brush backup roll 76, and is photosensitive by the primary transfer roll 66. The toner image carried on the body 50 is transferred. Each of the primary transfer roll 66, the wrap-in roll 68, the wrap-out roll 70, the scraper backup roll 74, and the brush backup roll 76 is provided with bearings 104 (see FIG. 5) at both ends. , 100b. The secondary transfer backup roll 72 includes a shaft portion 106 and a rotating portion 108 that rotates around the shaft portion 106, and both ends of the shaft portion 106 are fixed to side frames 100 a, 110 by fixing members 110, 110 such as screws. It is being fixed to 100b, respectively.

  The side frame 100 a passes through the rotation support shaft 49 of the photosensitive member 50, and passes through the hole 112 that supports one end of the rotation support shaft 49 via the bearing 111 and the rotation support shaft 89 of the intermediate transfer member cleaner 82. And the rotation support shaft 49 and the rotation support shaft 89 protrude sideways. A concave portion 116 (see FIG. 7) for engaging a later-described protrusion 140 of the protective cover 102a is provided on the upper side of the side frame 100a on the photosensitive member 50, and an upper portion of the protective cover 102a on the intermediate transfer member cleaner 82 side is provided. A hole 120 in which the fixing portion 142 is fixed by the fixing member 110 is provided. A concave portion 122 that engages a projection 144 described later of the protective cover 102b is provided at the lower portion of the side frame 100a on the intermediate transfer member cleaner 82 side, and a fixing portion 146 of the protective cover 102b is fixed on the lower side of the photosensitive member 50 side. A hole 126 fixed by the member 110 is provided.

  Further, the side frame 100 a is provided with a fixing portion 128 that fixes one end of the shaft portion 106 of the secondary transfer backup roll 72 with the fixing member 110. Further, inside the side frame 100a, a receiving portion 130 (in FIG. 5) that supports one end of a wrap-in roll 68, a wrap-out roll 70, a scraper backup roll 74, and a brush backup roll 76 from the side via a bearing 104. Side frames 100b) are provided. Note that one end of the primary transfer roll 66 is supported by the side frame 100a via a bearing 104 and a holder (not shown).

  The side frame 100 b passes through the rotation support shaft 49 of the photosensitive member 50, and passes through the notch 134 that supports one end of the rotation support shaft 49 via the bearing 132 and the rotation support shaft 89 of the intermediate transfer member cleaner 82. And the rotation support shaft 49 and the rotation support shaft 89 protrude sideways. The notch 134 has a narrower portion through which the rotation support shaft 49 passes than a portion to which the bearing 132 is attached. The bearing 132 is fixed to the side frame 100b by a fixing member such as a screw (not shown). A recess 116 (see FIG. 7) for engaging a later-described protrusion 140 of the protective cover 102a is provided on the upper side of the side frame 100b on the photoreceptor 50 side, and an intermediate transfer body cleaner 82 side upper part of the protective cover 102a is provided on the upper side. A hole 120 is provided in which a fixing portion 142 to be described later is fixed by the fixing member 110. A concave portion 122 that engages a projection 144 described later of the protective cover 102b is provided at the lower portion of the side frame 100b on the intermediate transfer member cleaner 82, and a fixing portion 146 described later of the protective cover 102b is provided at the lower portion of the photosensitive member 50 side. Is provided with a hole 126 that is fixed by the fixing member 110.

  The side frame 100 b is provided with a fixing portion 128 that fixes one end of the shaft portion 106 of the secondary transfer backup roll 72 with the fixing member 110. Further, inside the side frame 100b, a receiving portion 130 that supports one end of a wrap-in roll 68, a wrap-out roll 70, a scraper backup roll 74, and a brush backup roll 76 from the side via a bearing 104 (see FIG. 5). ) Are provided. Note that one end of the primary transfer roll 66 is supported by the side frame 100b via a bearing 104 and a holder (not shown).

  The protective cover 102a includes a cover main body 135a, a gripping portion 136, a convex portion 138, protrusions 140 and 140, and fixing portions 142 and 142. The cover main body 135a is made of, for example, ABS resin and has elasticity, and covers the intermediate transfer member 64 and the intermediate transfer member cleaner 82. The gripper 136 is made of, for example, a flexible member, and is provided on the upper surface of the cover main body 135a so that an operator can grip the image forming unit 96. The convex portion 138 is formed integrally with, for example, the cover main body 135a, protrudes so as to face the fixing device 90 (see FIG. 1), and foreign matter placed on the upper surface of the cover main body 135a is mixed into the image forming apparatus main body 12. To prevent. The protrusions 140 and 140 engage with the recesses 116 and 116 of the side frames 100a and 100b, respectively. The fixing portions 142 and 142 are fixed to the holes 120 and 120 of the side frames 100a and 100b by the fixing members 110 and 110, respectively. Is done.

  The protective cover 102b includes a cover main body 135b, protrusions 144 and 144, and fixing portions 146 and 146. The cover main body 135b is made of, for example, ABS resin and has elasticity, and is curved so as to cover the intermediate transfer member 64 and the intermediate transfer member cleaner 82. The protrusions 144 and 144 engage with the recesses 122 and 122 of the side frames 100a and 100b, respectively. The fixing portions 146 and 146 are fixed to the holes 126 and 126 of the side frames 100a and 100b by the fixing members 110 and 110, respectively. The

  That is, the side frames 100a and 100b are disposed substantially parallel to the rotation direction of the photosensitive member 50 and the intermediate transfer member 64, and the protective covers 102a and 102b and the secondary transfer backup cover the upper and lower portions of the intermediate transfer member 64, respectively. The shafts 106 of the roll 72 are connected to each other at three positions to determine the relative positions of the respective parts constituting the image forming unit 96 and to the sides of the photosensitive member 50, the intermediate transfer device 62, and the intermediate transfer member cleaner 82. Cover. Further, since both ends of the shaft portion 106 of the secondary transfer backup roll 72 are fixed to the side frames 100a and 100b, the image forming unit 96 is exposed in a stable state near the secondary transfer position of the intermediate transfer body 64. Yes.

  On the other hand, the protective covers 102a and 102b have elasticity as described above, and one ends thereof are alternately fixed to the side frames 100a and 100b. The primary transfer roll 66, the wrap-in roll 68, the wrap-out roll 70, the scraper backup roll 74, and the brush backup roll 76 are supported by the side frames 100a and 100b via bearings 104, respectively, and the side frames 100a and 100b. Have play against. As described above, the primary transfer roll 66, the wrap-in roll 68, the wrap-out roll 70, the scraper backup roll 74, and the brush backup roll 76 have a play that turns with respect to the side frames 100a and 100b around one end thereof. However, the range of this play is limited by the protective covers 102a and 102b.

  That is, the image forming unit 96 has a degree of freedom in which twisting occurs while the vicinity of the secondary transfer position of the intermediate transfer body 64 is exposed in a stable state.

  10 and 11 show the image forming unit 96 at the time of shipment. A protective paper 101 is detachably attached to the support frame 99 of the image forming unit 96. Here, as shown in FIGS. 2 and 12, in the image forming unit 96, the developing surface 50a of the photoconductor 50 on which the toner image is developed from the developing rolls 46a to 46d, and the intermediate image where the toner image is secondarily transferred to the sheet. The transfer surface 64 a of the transfer body 64 is exposed from the support frame 99. Therefore, the protective paper 101 is attached to the support frame 99 so as to cover the exposed developed surface 50a and transfer surface 64a.

  As shown in FIGS. 11 and 12, a snap piece 103 is formed on the lower surface of the support frame 99, that is, on the central portion of the protective cover 102b. The snap piece 103 is formed by forming a U-shaped hole 103a in the central portion of the protective cover 102b and projecting a portion between the U-shaped hole 103a to the outside by the thickness of the protective cover 102b. Has been. Note that the snap piece 103 is opened toward the photosensitive member 50, that is, in the direction in which a protective paper 101 to be described later is extracted (the direction of arrow A in FIG. 12). The snap piece 103 can be elastically deformed.

  As a result, as shown in FIG. 11, the central portion of the end of the protective paper 101 in the extraction direction can be inserted into the snap piece 103 and can be held between the snap piece 103 and the protective cover 102b.

  Then, as shown in FIGS. 10 to 12, the protective paper 101 having the back end in the extraction direction sandwiched between the snap piece 103 and the protective cover 102b is wound around the photoreceptor cleaner 54 and is extracted in the extraction direction. The front end of the cover is taped to the cover body 135a with the tape 105. Thus, the developing surface 50a of the photoconductor 50 and the transfer surface 64a of the intermediate transfer body 64 are covered with the protective paper 101 and protected.

  The protective paper 101 is black paper containing carbon, and shields the developing surface 50a of the photoconductor 50 and the transfer surface 64a of the intermediate transfer body 64 from light. In addition, a warning display 101a is printed on the portion of the protective paper 101 that covers the transfer surface 64a of the intermediate transfer member 64 to alert the user not to touch the transfer surface 64a of the intermediate transfer member. This is because the intermediate transfer body 64 is black and can easily be seen integrally with the black support frame 99, and the user easily touches the transfer surface 64a of the intermediate transfer body 64 inadvertently.

  As shown in FIG. 5, a rectangular silver mark 202 is attached to the surface of the intermediate transfer member 64. As shown in FIG. 12, the mark 202 can be exposed from the exposure window 200 formed in the protective cover 102b. As shown in FIG. 11, when the protective paper 101 is attached, the exposed window 200 is covered and hidden by the protective paper 101, and the mark 202 is not exposed.

  Next, a method for mounting the new image forming unit 96 with the protective paper 101 attached to the image forming apparatus main body 12 will be described.

  As shown in FIG. 13, the protective paper 101 is attached to the new image forming unit 96. However, in the image forming apparatus 10 of this embodiment, the image forming unit 96 is formed with the protective paper 101 attached. Attached to the apparatus main body 12. Then, as shown in FIG. 14, the tape 105 is peeled off from the cover main body 135a. In this state, the rear side end portion of the protective paper 101 in the extraction direction is only inserted into the snap piece 103 and is held between the support frame 99 and the image forming apparatus main body 12. A gap more than the thickness of the protective paper 101 is left between the two. Therefore, the protective paper 101 is sandwiched by the nip force between the developing surface 50a of the photoconductor 50 and the developing rolls 46a to 46d and the nip force between the transfer surface 64a of the intermediate transfer body 64 and the secondary transfer roll 80. It ’s just that.

  As a result, as shown in FIGS. 13 to 15, after the image forming unit 96 is mounted on the image forming apparatus main body 12, the protective paper 101 can be easily extracted from between the image forming apparatus main body 12 and the support frame 99. Can do.

  Accordingly, the image forming unit 96 can be mounted on the image forming apparatus main body 12 with the protective paper 101 attached, so that the developing surface 50a of the photoconductor 50 and the transfer surface 64a of the intermediate transfer body 64 can be touched by hand. It is possible to prevent the image forming apparatus main body 12 from being directly applied and damaged.

  As shown in FIG. 1, the image forming apparatus main body 12 is provided with an ADC sensor 107 facing the transfer surface 64 a of the intermediate transfer body 64. The ADC sensor 107 is a reflective sensor that emits light toward the transfer surface 64a and detects the amount of light reflected by the transfer surface 64a, and detects density detection of the toner image on the transfer surface 64a during a printing operation. It functions as a sensor.

  The image forming apparatus main body 12 is provided with a TR0 sensor 78 at a position facing the exposure window 200 (see FIG. 12). The TR0 sensor 78 is a reflective sensor that emits a light beam toward the exposure window 200 and detects the amount of the reflected light beam. Note that the surface of the intermediate transfer member 64 is coated and glossy, and therefore has a higher light reflectance than the protective paper 101. (In other words, the amount of reflected light is large). Further, since the mark 202 is silver, the reflectance is higher than that of the intermediate transfer member 64. (In other words, the amount of reflected light is the largest). The TR0 sensor 78 can detect the difference in the amount of light reflected by the intermediate transfer body 64, the protective paper 101, and the mark 202.

  The detection position at which the TR0 sensor 78 detects the mark 202 of the intermediate transfer member 64 that rotates during image formation is the reference position for image formation in the rotation direction of the intermediate transfer member 64. In other words, each color image is written using the mark 202 as a reference position.

  As shown in FIGS. 1 and 8, the image forming apparatus main body 12 is provided below the rotation support shaft 49 as detection means for detecting whether or not the image forming unit 96 is mounted on the image forming apparatus main body 12. A switch 250 is provided. As shown in FIG. 1, when the image forming unit 96 is attached to the image forming apparatus main body 12, the rotary support shaft 49 pushes down the lever 252, so that the switch 250 is turned on. As shown in FIG. 8, if the image forming unit 96 is not attached, the lever 252 is not pushed down, so that the switch 250 is turned off.

  Next, the operation of the above embodiment will be described.

  When the image forming signal is sent, the photosensitive member 50 is uniformly charged by the charging device 52, and light is emitted from the exposure device 60 to the charged photosensitive member 50 based on the image signal. The light beam from the exposure device 60 exposes the surface of the photoconductor 50 to form a latent image. The latent image of the photoreceptor 50 formed by the exposure device 60 is developed with yellow, magenta, cyan, and black toner images by the rotary developing device 38 and is primarily transferred onto the intermediate transfer member 64. In the primary transfer, waste toner remaining on the photoreceptor 50 is scraped off and collected by the image carrier cleaner 54.

  On the other hand, the paper stored in the paper feed cassette 22 by a paper feed signal or the like is sent out by the feed roll 24, is turned by the retard roll 26, is guided to the transport path 28, is temporarily stopped by the registration roll 32, and the timing is reached. As a result, it is guided between the secondary transfer roll 80 and the secondary transfer backup roll 72. When the sheet is guided between the secondary transfer roll 80 and the secondary transfer backup roll 72, the toner image primarily transferred to the intermediate transfer body 64 is transferred to the sheet by the secondary transfer roll 80 and the secondary transfer backup roll 72. Secondary transfer. After the secondary transfer, the waste toner remaining on the intermediate transfer member 64 is scraped off and collected by the intermediate transfer member cleaner 82.

  The sheet on which the toner image has been transferred is guided to the fixing device 90, and the toner image is fixed by the thermal pressure by the pressure roll 94 by the heating roll 92. The sheet on which the toner image is fixed is discharged from the discharge port 30 to the discharge unit 36 by the discharge roll 34.

  When the image forming unit 96 has a service life, for example, the control unit 109 counts the number of prints and reaches a predetermined number of prints, and the image forming unit 96 needs to be replaced, the control unit 109 forms an image on the operation panel 210. A display prompting replacement of the unit 96 is performed. The user views the display and replaces it with a new image forming unit 96 (in other words, an unused image forming unit 96).

  At the time of shipment, the new image forming unit 96 is positioned so that the mark 202 is exposed from the exposure window 200 by rotating the intermediate transfer body 64 as shown in FIGS. That is, when the image forming unit 96 is attached to the image forming apparatus main body 12, the TR0 sensor 78 of the image forming apparatus main body 12 is set to a position where the mark 202 can be detected. When the protective paper 101 is attached, the exposure window 200 is covered and the mark 202 is hidden.

  As shown in FIG. 13, the user attaches a new image forming unit 96 to the image forming apparatus main body 12 and removes the protective paper 101 as shown in FIG.

  Now, at a predetermined timing, for example, when the image forming apparatus 10 is powered off or on, or when the image forming unit 96 is mounted on the image forming apparatus main body 12 and the switch 250 is turned on, the control unit 109 detects the TR0 sensor 78. To detect the light intensity.

  If the amount of light detected by the TR0 sensor 78 is the amount of light reflected by the mark 202, the control unit 109 determines that the image forming unit 96 is new. Then, the count of the number of printed sheets is reset to 0 and the display for prompting replacement of the image forming unit 96 on the operation panel 210 is turned off.

  However, if the amount of light detected by the TR0 sensor 78 is not the amount of light reflected by the mark 202 but the amount of light reflected by the intermediate transfer body 64, the control unit 109 does not determine that the image forming unit 96 is new. Therefore, the count of the number of printed sheets is not reset, and the display prompting the replacement of the image forming unit 96 on the operation panel 210 is not erased.

  When the protective paper 101 is attached, the light amount detected by the TR0 sensor 78 is the light amount reflected by the protective paper 101. Therefore, the control unit 109 determines that the protective paper 101 remains attached. The control unit 109 prohibits the operation of each drive unit of the image forming apparatus main body 12 and the image forming unit 96 so that the printing operation is not performed even when a print command is received. In addition, a warning display indicating that the protective paper 101 is forgotten to be removed is displayed on the operation panel 210. Accordingly, even if the user forgets to remove the protective paper 101 from the image forming unit 96 after attaching the image forming unit 96 to the image forming apparatus main body 12, the protective paper 101 in the image forming apparatus main body 12 is attached to the image forming apparatus main body 12. There is no problem in each part of the main body 12 and the image forming unit 96.

  When the protective paper 101 is removed, as described above, it is determined whether or not the image forming unit 96 is new based on the light amount of the TR0 sensor 78.

  When a new image forming unit 96 is mounted on the image forming apparatus main body 12 and used, the intermediate transfer member 64 rotates with image formation. Then, the control unit 109 controls the rotation of the intermediate transfer body 64 so that the mark 202 stops at a position where the mark 202 is not exposed from the exposure window 200 (in other words, a position where the TRO sensor 78 does not detect the mark 202). Therefore, in the used image forming unit 96, the mark 202 is not accidentally stopped in a state where the mark 202 is exposed from the exposure window 200 (in other words, a position where the TRO sensor 78 detects the mark 202). Therefore, the used image forming unit 96 is not erroneously determined as a new image forming unit 96.

  As described above, the mark 202 for detecting the reference position for image formation and the TR0 sensor 78 are used to detect whether the image forming unit 96 is new and the protective paper 101 has been removed. Both detection and non-detection can be detected. That is, both the detection of whether or not the installed image forming unit 96 is new and the detection of whether or not the protective paper 101 is removed can be performed at low cost.

  The present invention is not limited to the above embodiment.

  For example, in the above embodiment, the exposed portion of the intermediate transfer member 64 is covered with the protective paper 101, but the present invention is not limited to this. Even if it is not a sheet form, it may be protected by a rigid cover made of resin or the like.

  Further, the mark 202 has a rectangular silver mark stuck on the surface of the intermediate transfer body 64, but is not limited thereto. Other forms may be used as long as they are marks for the intermediate transfer member 64. For example, a mark applied to the intermediate transfer body 64, a hole opened in the intermediate transfer body 64, or the like may be used.

  For example, in the above embodiment, the intermediate transfer member 64 has been described as an example. However, the present invention is not limited to this, and the photosensitive member 50 or other image carrier may be used. The image forming unit 96 has been described as an example. However, the image forming unit 96 is not limited thereto, and the image forming unit includes only the photosensitive member 50 and only the intermediate transfer member 64, and the image forming unit including the photosensitive member and the developing device. The present invention is applicable.

1 is a side view of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing an image forming unit of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view showing a state in which the image forming unit shown in FIG. 2 is disassembled into an intermediate transfer body assembly and a photoreceptor unit. FIG. 3 is an exploded perspective view of the image forming unit shown in FIG. 2. FIG. 3 is an exploded perspective view of the image forming unit shown in FIG. 2 as viewed from below except for a protective cover. FIG. 3 is an exploded perspective view showing a connection between a lower protective cover and a side frame of the image forming unit shown in FIG. 2. FIG. 3 is an enlarged view showing engagement between a protective cover on the upper side of the image forming unit shown in FIG. 2 and a side frame portion. 1 is a side view showing a state where an image forming unit of an image forming apparatus according to an embodiment of the present invention is removed from an image forming apparatus main body. 1 is a side view schematically showing a direction in which an image forming unit of an image forming apparatus according to an embodiment of the present invention is attached to an image forming apparatus main body. 1 is a perspective view showing an image forming unit of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing an image forming unit of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing an image forming unit of an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing a state in which an image forming unit of an image forming apparatus according to an embodiment of the present invention is mounted on an image forming apparatus main body. 1 is a perspective view showing a state in which an image forming unit of an image forming apparatus according to an embodiment of the present invention is mounted on an image forming apparatus main body. 1 is a perspective view showing a state in which an image forming unit of an image forming apparatus according to an embodiment of the present invention is mounted on an image forming apparatus main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 64 Intermediate transfer body (image carrier)
64a Transfer surface (exposed part)
78 TR0 sensor (detector)
96 Image forming unit 101 Protective paper (protective sheet)
102b Protective cover (housing)
103 snap piece (protective sheet holding means)
200 Exposed window 202 Mark

Claims (7)

An image forming unit on which a toner image is formed and includes at least a rotating image carrier, and is attachable to and detachable from an image forming apparatus body;
A mark provided on the image carrier and exposed from the image forming unit;
A detector provided in the image forming apparatus main body for detecting the mark exposed from the image forming unit;
Have
When the image forming unit is mounted on the image forming apparatus main body, the mark of the unused image forming unit becomes a position that can be detected by the detection unit,
When the image forming unit is used, the image carrier rotates, and the image carrier stops so that the mark is not detected by the detection unit,
The image forming apparatus according to claim 1, wherein the mark also serves as a reference mark serving as a reference position when a toner image is formed on the image carrier.   The unused image forming unit is provided with a protective member that covers the exposed portion where the image carrier is exposed from the image forming unit and the exposed mark, and is removable from the image forming unit. The image forming apparatus according to claim 1, wherein:   The image forming apparatus according to claim 2, wherein the detection unit can detect the mark and the protection member separately. An image forming unit on which a toner image is formed and includes at least a rotating image carrier, and is attachable to and detachable from an image forming apparatus body;
A mark provided on the image carrier and exposed from the image forming unit;
A detector provided in the image forming apparatus main body for detecting the mark exposed from the image forming unit;
Have
When the image forming unit is mounted on the image forming apparatus main body, the mark of the unused image forming unit becomes a position that can be detected by the detection unit,
When the image forming unit is used, the image carrier rotates, and the image carrier stops so that the mark is not detected by the detection unit,
The unused image forming unit is covered with an exposed portion where the image carrier is exposed from the image forming unit, and the exposed mark, and a protective member removable from the image forming unit is attached,
The image forming apparatus, wherein the detection unit can detect the mark and the protection member separately.   The image forming apparatus according to claim 4, wherein the mark also serves as a reference mark serving as a reference position when a toner image is formed on the image carrier. The protective member is a sheet-like protective sheet,
The image forming unit includes a protective sheet supporting unit that supports the protective sheet so that the protective sheet can be removed from between the image forming unit and the image forming apparatus main body after being mounted on the image forming apparatus main body. The image forming apparatus according to claim 2, wherein the image forming apparatus is an image forming apparatus. The image forming unit includes a housing in which an exposure window capable of exposing the mark is formed,
The detection unit detects the mark exposed from the exposure window,
The image forming apparatus according to claim 1, wherein the mark of the unused image forming unit is exposed from the exposure window.

Images