JP2009116231A - Toner density detector and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner density detector configured to prevent toner from sticking to a detection part with opening/closing of an opening/closing member, and to provide an image forming apparatus. <P>SOLUTION: The toner density detector 72 includes: a detector main body 74; a detection part 76 disposed in the detector main body 74, for optically detecting the toner density; the opening/closing member 84 freely slidably disposed in the detector main body 74, for opening/closing the detection part 76; and a cover part 98 for covering a portion between the closing-direction end part of the opening/closing member 84 and the detector main body 74 in the state where the opening/closing member 84 is closed. The cover part 98 is disposed independently from the detector main body 74, and composed of an elastic body that comes in contact with the opening/closing member 84 when the detection part 76 is closed, and that is deformed in accordance with the contact of the opening/closing member 84. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a toner concentration detection device and an image forming apparatus.

In an image forming apparatus of a type that transfers toner to a sheet, a toner concentration detection device is provided in order to maintain an appropriate toner concentration.
Patent Document 1 discloses a technique in which a toner density detecting device is provided with an opening / closing member for preventing dirt from adhering to scattered toner.
Japanese Patent Application Laid-Open No. 2004-228688 discloses a technique for preventing the toner density detecting device from being scattered from the developing device to the toner density detecting device by disposing the toner density detecting device downstream of the transfer position in the rotation direction of the photosensitive member.

JP 2006-3399 A Japanese Patent Laid-Open No. 9-190023

The inventor of the present application provides an opening / closing member that opens and closes the detection unit of the toner concentration detection device, and the toner adheres to the detection unit even when the detection unit is closed by the opening / closing member when the toner concentration is not detected. It was discovered that the detection accuracy of may decrease. This is presumably because the toner, which is powder, enters between the detection device main body and the opening / closing member, drags the toner when the opening / closing member is opened, and the dragged toner adheres to the detection unit.
SUMMARY An advantage of some aspects of the invention is that it provides a toner concentration detection device and an image forming apparatus that can prevent toner from adhering to a detection unit by opening and closing an opening / closing member.

According to a first aspect of the present invention, there is provided a detection device main body, a detection unit that is provided in the detection device main body and optically detects a toner concentration, and is slidably provided in the detection device main body. A toner concentration detecting device having an opening / closing member that opens and closes and a cover portion that covers at least a part between a closing direction end of the opening / closing member and the detection device main body when the opening / closing member is in a closed state. is there.

  The present invention according to claim 2 is the toner concentration detection device according to claim 1, which is provided as a separate member from the main body of the detection device.

  According to a third aspect of the present invention, the cover portion is formed of an elastic body that abuts on the opening / closing member when the detection portion is closed and deforms in accordance with the abutment of the opening / closing member. It is a toner density | concentration detection apparatus of description.

  According to a fourth aspect of the present invention, the cover portion is bonded to the main body of the detection device via an adhesive layer, and the cover portion is elastically deformed when the detection portion is closed according to the width of the adhesive layer. 4. The toner concentration detecting device according to claim 3, wherein the amount is set.

The present invention according to claim 5 includes an image holding body that holds and conveys a toner image, and a toner density detection device that is disposed to face the image holding body, and the toner density detection device includes: A main body of the detection device, a detection unit provided in the main body of the detection device for optically detecting a toner concentration, an open / close member provided slidably on the main body of the detection device and opening / closing the detection unit; The image forming apparatus includes a cover portion that covers at least a part between a closing direction end portion of the opening and closing member and the detection device main body when the member is in a closed state.

  According to a sixth aspect of the present invention, the image carrier is composed of an endless belt, further includes a support roll around which the image carrier is wound to support the image carrier, and the toner of the detection unit The image forming apparatus according to claim 5, wherein the detection position is within a range in which the support image holding member is wound around the support roll.

  7. The image forming apparatus according to claim 7, further comprising a rotary type developing device, wherein the toner density detecting device is disposed at a position to receive an air flow generated by rotation of the developing device. Forming device.

  The present invention according to claim 8 further includes a sheet supply device that supplies a sheet onto which the toner image held by the toner holder is transferred, and is in a position to receive an air flow generated by the sheet supply by the sheet supply device. The image forming apparatus according to claim 5, wherein the toner density detecting device is disposed.

  According to the first aspect of the present invention, it is possible to provide a toner concentration detection device capable of preventing toner from adhering to the detection unit by opening and closing the opening / closing member.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, the material of the cover part can be selected regardless of the material of the detection device body, and the degree of freedom in design is improved. Can be made.

  According to the third aspect of the present invention, in addition to the effect of the present invention according to the first or second aspect, the cover portion can escape from the overshoot of the opening / closing member when the opening / closing member is closed, and the opening / closing member Can reduce repeated fatigue due to repeated contact with the cover portion, and can reduce the possibility of whitening due to repeated fatigue and further damage such as extension of whitening.

  According to the fourth aspect of the present invention, in addition to the effect of the present invention according to the third aspect, the elastic deformation amount of the cover portion when the detection portion is closed is easily set according to the material and length of the opening / closing member. can do.

  According to the fifth aspect of the present invention, it is possible to provide an image forming apparatus capable of preventing toner from adhering to the detection unit by opening and closing the opening / closing member.

  According to the sixth aspect of the present invention, in addition to the effect of the present invention according to the fifth aspect, the distance between the toner holding body constituted by an endless belt and the detection unit can be kept constant, and the toner The concentration can be accurately detected.

  According to the seventh aspect of the present invention, in addition to the effect of the present invention according to the fifth or sixth aspect, the toner carried on the air flow generated by the rotation of the rotary developing device is transferred to the toner concentration detecting device. Can be prevented from adhering to the detector.

  According to the eighth aspect of the present invention, in addition to the effect of the present invention according to any one of the fifth to seventh aspects, the toner carried by the air flow generated by the sheet supply is detected by the detection unit of the toner concentration detection device. Can be prevented.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view showing 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, in which the photosensitive member 14, the charging device 16, the optical writing device 18, the developing device 20, the intermediate transfer device 22, the cleaning device 24, and the fixing device. 26 is stored. The photoconductor 14 rotates in the clockwise direction in the drawing and is used as a latent image holder that forms and holds a latent image. The charging device 16 includes a charging roll that uniformly charges the photoreceptor 14. The optical writing device 18 writes a latent image on the photosensitive member 14 charged by the charging device 16 with a laser beam.

  The developing device 20 is a rotary type, and a rotating body 30 that rotates counterclockwise in the drawing with the rotation shaft 28 as a rotation center, and yellow, yellow, magenta, and cyan that are mounted on the rotating body 30. ) And black (Black) four color toner images, respectively, and a toner cartridge 34 in which toner to be supplied to each developer 32 is stored.

  The rotator 30 holds the developing device 32 at 90 ° intervals, rotates 90 ° counterclockwise in the figure, and moves the developing device 32 to a position where the latent image formed on the photoconductor 14 is developed. Let

  The intermediate transfer device 22 transfers an intermediate transfer belt 36, which is an endless intermediate transfer member used as an image holding member for holding a toner image on the surface, and a toner image on the photosensitive member 14 to the intermediate transfer belt (primary transfer). A primary transfer roll 38, a wrap-in roll 40 and a wrap-out roll 42 that are located near the photoreceptor 14 and hold the intermediate transfer belt 36 from the inside, and the intermediate transfer belt 36 is wound around to support the intermediate transfer belt 36. A plurality of supporting rolls 44. Further, the intermediate transfer device 22 has a secondary transfer roll 46 facing one support roll 44.

  The intermediate transfer belt 36 rotates in the counterclockwise direction in the drawing, and the toner image on the photoconductor 14 is superimposed on the intermediate transfer belt 36 in the order of, for example, yellow, magenta, cyan, and black by the primary transfer roll 38. The intermediate transfer belt 36 conveys the primary transferred toner image between the support roll 44 and the secondary transfer roll 46. On the other hand, the sheet is conveyed between the support roll 44 and the secondary transfer roll 46, and the toner image primarily transferred to the intermediate transfer belt 36 is transferred to the conveyed sheet.

  The cleaning device 24 includes a cleaning blade 48 that scrapes off toner remaining on the photosensitive drum 14 after temporary transfer, and a toner recovery bottle 50 that recovers the toner scraped off by the cleaning blade 48.

  The fixing device 26 includes a heating roll 54 and a pressure roll 52. The fixing device 26 applies heat and pressure to a sheet passing between the heating roll 54 and the pressure roll 52, and the second-transferred toner image is transferred to the sheet. To settle.

  The sheet supply device 56 includes a sheet supply cassette 58 in which sheets are stored, a pickup roll 60 that sends out a sheet from the sheet supply cassette 58, a feed roll 62 that conveys the sheet sent out by the pickup roll 60, and the feed roll 62. And a retard roll 64 for separating sheets one by one. The sheet supplied from the sheet supply device 56 is temporarily stopped by the registration roll 66, and between the support roll 40 and the secondary transfer roll 42 according to the timing at which the toner image formed on the intermediate transfer belt 36 is conveyed. It is conveyed to. A toner image is transferred to the sheet conveyed between the support roll 40 and the secondary transfer roll 42, the toner image is fixed by the fixing device 26, and a discharge unit 68 provided on the upper surface of the image forming apparatus main body 12. It is discharged through the discharge roll 70.

  The toner density detection device 72 is for detecting the density of the toner conveyed by the intermediate transfer belt 36. In this embodiment, the intermediate transfer belt 36 of the support roll 44 positioned at the lowermost position is wound. The image forming apparatus main body 12 supports the detection position in the vicinity of the upstream contact with the support roll 44 of the intermediate transfer belt 36 within the range. The toner concentration detection device 72 is in a space surrounded by the intermediate transfer belt 36, the toner recovery bottle 50, and the sheet supply cassette 58, and is generated by the air flow generated by the rotation of the developing device 20 and the sheet supply of the sheet supply device 56. The air flow such as the generated air flow is received. A part of the toner put in the air flow soars from the lower side of the toner concentration detection device 72 toward the lower surface of the toner concentration detection device 72. The toner density detection device 72 detects the density of test toner images (toner patches) sequentially written on the intermediate transfer belt 36 when the image forming apparatus 10 is in the test mode. Based on the toner concentration detected by the toner concentration detection device 72, the amount of toner supplied from the toner cartridge 34 to the developing device 32 is controlled.

Further, the toner density detecting device 72 will be described in detail.
2 is a perspective view of the toner concentration detection device 72, and FIG. 3 is a front view of the toner concentration detection device 72. As shown in FIG. The toner concentration detection device 72 includes a detection device main body 74, and a detection unit 76 that optically detects the toner concentration is provided in the detection device main body 74. In this embodiment, the detection unit 76 includes a light emitting unit 78 in which a light emitting element made of, for example, an LED is incorporated, and a first light receiving unit that receives light emitted from the light emitting unit 78 that is regularly reflected on the intermediate transfer belt 36. A first light receiving unit 80 including an element and a second light receiving unit 82 including a second light receiving element that receives light emitted from the light emitting unit 78 diffusely reflected by the toner on the intermediate transfer belt 36. It consists of and. Further, the detection device main body 74 incorporates circuits such as a drive circuit for driving the light emitting element and a converter for converting a current output from the light receiving element into a voltage. Then, the toner density is calculated based on the outputs of the first light receiving element and the second light receiving element.

  The opening / closing member 84 is formed in a plate shape, and an end portion of the opening / closing member 84 is rotatably connected to a support portion 88 provided on the detection side surface 86 of the detection device main body 74, and is detected using the support portion 86 as a fulcrum. It rotates while sliding on the side surface 86. The opening / closing member 84 is formed with a guide portion 90 projecting toward the detection device main body 74, the detection device main body 74 is formed with a guide groove 92, and the guide portion 90 is fitted in the guide groove 92. The member 84 is guided to move between an open position and a closed position. Further, an urging member 94 made of, for example, a spring is provided between the detection device main body 74 and the opening / closing member 84. When the opening / closing member 84 is in the open position and the closed position, respectively. At this position, the opening / closing member 84 is urged in a direction in which the opening / closing member 84 is fixed, so that the opening / closing member 84 is prevented from moving with respect to the detection device main body 74 due to external vibration or the like. The closing member 84 is connected to an actuator 96 composed of a solenoid or the like, and is moved between an open position and a closed position by the actuator 96. When the opening / closing member 84 is in the open position, the detection unit 76 is opened and the toner density can be detected. When the opening / closing member 84 is in the closed position, the detection unit 76 is closed and the toner density is not detected. On the other hand, the toner is prevented from adhering to the detection unit 76. When the opening / closing member 84 is in the closed position, the end in the closing direction of the opening / closing member 84 substantially coincides with the lower surface of the detection device main body 74.

  The cover portion 98 is provided on the detection device main body 74 so as to cover between the end portion of the opening / closing member 84 in the closing direction and the detection device main body 74 when the opening / closing member 84 is in the closed position. In this embodiment, the cover portion 98 is configured as a separate member from the detection device main body 74, and covers the closing direction end portion of the opening / closing member 84 over substantially the entire length of the opening / closing member 84. Specifically, the cover portion 98 is an elastic body made of a film made of PET (polyethylene terephthalate) having a thickness of 0.5 mm or less, preferably 0.2 mm or less. As shown in FIG. 4, the cover portion 98 is partially bonded to the lower surface of the detection device main body 74 via the adhesive layer 100 on the lower surface of the detection device main body 74. The cover portion 98 protrudes from the detection side surface 86 along the lower surface of the detection device main body 74, and a rising portion 102 that rises upward is formed at the protruding end portion. The protruding portion and the rising portion 102 constitute an opening / closing member. 84 covers the end in the closing direction. Thus, since the gap between the closing direction end of the opening / closing member 84 and the detection device main body 74 is covered with the cover 98, the toner rising from below adheres to the closing direction end of the opening / closing member 84, or the opening / closing member 84. And the detection device main body 74 can be prevented from entering.

When the opening / closing member 84 moves from the open position to the closed position, the cover portion 98 abuts on the closing direction end of the opening / closing member 84. At this time, as shown in FIG. 5, the opening / closing member 84 is bent and deformed with the momentum when the opening / closing member 84 is closed, and an overshoot is generated in which the tip side protrudes downward from the lower surface of the detection device main body 74. However, since the cover portion 98 is made of an elastic body, the cover portion 98 is elastically deformed according to the bending of the opening / closing member 84, and the impact caused by the contact of the opening / closing member 84 with the cover portion 98 is reduced.

  As described above, the cover portion 98 is elastically deformed by the contact of the opening / closing member 84, but the amount of elastic deformation needs to be appropriately set depending on the material and length of the opening / closing member 84. In this embodiment, as shown in FIG. 4, the width d <b> 1 of the adhesive layer 100 in the direction orthogonal to the detection side surface 86 is set. That is, when the width d1 of the adhesive layer 100 in the direction orthogonal to the detection side surface 86 is changed, the length of the cover portion 98 from the end portion to the front end of the adhesive layer 100 changes, and the elastic deformation amount d2 of the cover portion 98 is adjusted. be able to.

Further, the advantages of the above-described embodiment in which the cover portion 98 is made of a film such as PET as a separate member from the detection device main body 74 will be described.
FIG. 6 shows another embodiment in which the cover portion 98 is formed integrally with the detection device main body 74. The detection device main body 74 is made of plastic, and is molded so that the cover portion 98 is integrated. Normally, when molding, all parts are designed to have the same thickness. In this embodiment, the distance d3 between the detection side surface 86 of the toner concentration detection device 72 and the intermediate transfer belt 36 is used. Is preferably closer to improve the detection accuracy, and the cover portion 98 may be thinner than the detection device main body 74 in some cases. However, when the cover portion 98 is thinned, the opening / closing member 84 overshoots and repeatedly comes into contact, so that the base 104 portion of the cover portion 98 is whitened. There is a risk of destruction from the part.
However, in the above-described embodiment, the cover portion 98 is elastically deformed according to the bending of the opening / closing member 84, so that the impact caused by the contact of the opening / closing member 84 with the cover portion 98 is reduced.

  In the above embodiment, the cover 98 is configured to cover substantially the entire closing direction end of the opening / closing member 84. However, the present invention is not limited to this, and for example, only the detection unit 76 portion. May be covered. In the above embodiment, the cover 98 is provided on the detection device main body 74. However, the present invention is not limited to this, and for example, a support for supporting the detection device main body 74 on the image forming apparatus main body 12. You may provide in a part. In the above embodiment, the target for detecting the toner density is the intermediate transfer belt 36. However, the present invention is not limited to this, and the photosensitive member 14 may be the target.

1 is a cross-sectional view illustrating an image forming apparatus according to an embodiment of the present invention. 1 is a perspective view showing a toner concentration detection device according to an embodiment of the present invention. 1A and 1B show a toner concentration detection device according to an embodiment of the present invention, in which FIG. 1A is a front view showing a state where an opening / closing member is in a closed position, and FIG. 2B is a front view showing a state where the opening / closing member is in an open position. FIG. 4 is a side view showing a relationship between a cover portion and an adhesive layer in the toner concentration detection device according to the embodiment of the present invention. FIG. 4 is a side view showing a relationship between a detection device main body and an opening / closing member in the toner concentration detection device according to the embodiment of the present invention. It is sectional drawing which shows a part of toner density | concentration detection apparatus of other embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Image forming apparatus main body 14 Photoconductor 20 Developing apparatus 36 Intermediate transfer belt 44 Support roll 72 Toner density detection apparatus 74 Detection apparatus main body 76 Detection part 84 Opening and closing member 98 Cover part 100 Adhesive layer

Claims (8)

A detection device body;
A detection unit provided in the main body of the detection device for optically detecting the toner concentration;
An opening / closing member that is slidably provided on the detection device main body and opens and closes the detection unit;
A cover portion that covers at least a part between a closing direction end of the opening and closing member and the detection device main body when the opening and closing member is in a closed state;
A toner concentration detecting device.   The toner concentration detection device according to claim 1, wherein the cover is provided as a separate member from the detection device main body.   3. The toner concentration detection device according to claim 2, wherein the cover portion is formed of an elastic body that abuts on the opening / closing member when the detection portion is closed and deforms in accordance with the contact of the opening / closing member.   The said cover part is adhere | attached through the contact bonding layer with respect to the said detection apparatus main body, and the elastic deformation amount of the said cover part in the case of closing the said detection part according to the width | variety of the said contact bonding layer is set. The toner concentration detection device according to claim. An image carrier that holds and conveys the toner image;
A toner concentration detection device disposed opposite to the image carrier,
The toner concentration detection device includes:
A detection device body;
A detection unit provided in the main body of the detection device for optically detecting the toner concentration;
An opening / closing member that is slidably provided on the detection device main body and opens and closes the detection unit;
A cover portion that covers at least a part between a closing direction end of the opening and closing member and the detection device main body when the opening and closing member is in a closed state;
An image forming apparatus. The image carrier is composed of an endless belt,
A support roll that supports the image holding body around which the image holding body is wound;
The image forming apparatus according to claim 5, wherein a toner detection position of the detection unit is within a range in which the image holding member is wound around the support roll.   7. The image forming apparatus according to claim 5, further comprising a rotary type developing device, wherein the toner density detecting device is disposed at a position for receiving an air flow generated by rotation of the developing device.   The apparatus further includes a sheet supply device that supplies a sheet to which a toner image held by the toner holder is transferred, and the toner concentration detection device is disposed at a position that receives an air flow generated by the sheet supply by the sheet supply device. The image forming apparatus according to claim 5.

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