JP2018146664A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a reduction in image density at a developer delivery end side, compared with a case where an image forming apparatus does not comprise developer discharge means that forms images in non-image areas on both ends along a direction intersecting with a conveyance direction of a recording medium in an image holding body, the means discharging developer in a smaller amount at the delivery end side of developing means than that at the other side.SOLUTION: An image forming apparatus comprises: image forming means that transfers, to a continuous recording medium, an image obtained by developing a latent image on an image holding body with developing means including a supply member that supplies developer consisting of toner and carrier to a developer holding body and a conveying member that conveys the developer peeled off from the developer holding body to deliver to the supply member at a delivery end, to form an image; and developer discharge means that forms images in non-image areas on both ends along a direction intersecting with a conveyance direction of the recording medium in the image holding body, the means discharging the developer in a smaller amount at the delivery end side of the developing means than that at the other side.SELECTED DRAWING: Figure 10

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus, in order to respond to diversification of needs, there is an image forming apparatus configured to form an image on a continuous recording medium other than a so-called cut sheet cut to a required size as a recording medium. Various proposals have been made. In such an image forming apparatus, as compared with an apparatus that forms an image on a normal cut sheet, there is no non-image portion between images where no recording medium exists, such as between the recording medium and the recording medium. Therefore, this type of image forming apparatus cannot discharge a deteriorated toner by forming a toner band in a non-image portion located between images.

  Therefore, a technique disclosed in Patent Document 1 has already been proposed as a technique for suppressing toner deterioration in an image forming apparatus that forms an image on a continuous recording medium. Further, as an image forming apparatus that stabilizes the toner charge amount even when the developer toner density is changed for adjusting the developing ability, an image forming apparatus that uses the developing device according to Patent Document 2 has been proposed.

  Patent Document 1 discloses an image forming unit that forms an image on a continuous recording medium by transferring a toner image obtained by developing a latent image formed on a photoreceptor onto the continuous recording medium, and the continuous recording medium. The image is formed so that a predetermined image pattern is formed in a predetermined side area of the continuous recording medium outside the image area simultaneously with forming an image based on the image information on the recording medium in the predetermined image area. And a control means for controlling the forming means.

  Patent Document 2 includes, as a developing device, a supply-side conveyance space that supplies a developer to a developing sleeve, and a collection-side conveyance space that is adjacent to the supply-side conveyance space and collects the developer after development. Is provided with an agitating / conveying screw that is a stirring means parallel to the axial direction of the developing sleeve, and the developer agitated and conveyed by the agitating / conveying screw from the supply side conveying space to the developing sleeve. The developer that is supplied and remains in the developing sleeve after development moves to the collection-side conveyance space without returning to the supply-side conveyance space by the action of the repulsive magnetic pole built in the development sleeve, and is agitated and conveyed by the conveyance screw. It is configured as follows. The supply-side conveyance space and the collection-side conveyance space are partitioned by a partition member, and the developer is circulated through a communication portion in which the lacking portions at both ends of the partition member are used.

Japanese Patent Laying-Open No. 2015-055573 JP, 2006-114923, A (paragraphs [0095]-[0099])

  An object of the present invention is a means for forming an image in a non-image area at both ends along a direction intersecting the conveyance direction of the recording medium on the image carrier and discharging the developer, and discharging on the delivery end side of the developing means. The object is to suppress a decrease in image density on the delivery end side of the developer as compared with a case where the developer discharging means set to a smaller amount than the other side is not provided.

According to the first aspect of the present invention, a supply member for supplying a developer comprising toner and a carrier to the developer holding member and a developer peeled from the developer holding member are conveyed to the supply member at the delivery end. An image forming means for forming an image by transferring an image obtained by developing the latent image on the image holding member onto a continuous recording medium by a developing means having a delivery member;
A means for forming an image in a non-image area at both ends along a direction intersecting the conveyance direction of the recording medium of the image carrier and discharging the toner, and a discharge amount on the delivery end side of the developing means is Less developer discharge means than the other side;
An image forming apparatus.

  According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the developing unit has the supply member disposed above the conveying member in the vertical direction.

  A third aspect of the present invention is the image forming apparatus according to the second aspect, wherein the delivery end side of the developing means is a conveyance start end side of the supply member.

  The invention described in claim 4 is the image forming apparatus according to claim 1, wherein the developer discharging means sets a width of the image on the delivery end side to be narrower than that on the other side.

  The invention described in claim 5 is the image forming apparatus according to claim 1, wherein the developer discharging means sets the density of the image on the delivery end side lower than that on the other side.

  According to a sixth aspect of the present invention, the developer discharging means forms a plurality of images at intervals along the conveyance direction of the recording medium, and sets the interval between the images on the delivery end side to the other side. 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is set wider.

According to a seventh aspect of the present invention, the developing unit includes a density detecting unit that detects a toner concentration in the developer accommodated in the developing unit,
The image forming apparatus according to claim 1, wherein the density detecting unit is disposed on the delivery end side of the developing unit.

According to an eighth aspect of the present invention, the developing unit has a supply port that supplies a new developer to an upstream end of the transport member along the transport direction of the developer.
The image forming apparatus according to claim 1, wherein the supply port is disposed on a side opposite to the delivery end side of the developing unit.

The invention described in claim 9 includes a plurality of image forming means for forming different images from each other,
9. The image forming apparatus according to claim 1, wherein the developer discharge amount by the developer discharge unit is varied according to the image formation amount of each of the image forming units.

  According to the first aspect of the present invention, the developing unit is a unit that forms an image in the non-image areas at both ends along the direction intersecting the conveyance direction of the recording medium in the image carrier and discharges the developer. As compared with the case where the developer discharge means having a smaller discharge amount on the delivery end side than that on the other side is not provided, it is possible to suppress a decrease in image density on the delivery end side of the developer.

  According to the second aspect of the present invention, the developing unit can be reduced in size as compared with the case where the supply member is not disposed above the conveying member in the vertical direction.

  According to the third aspect of the present invention, in the developing unit that can be downsized, it is possible to suppress a decrease in image density on the delivery end side of the developer.

  According to the fourth aspect of the present invention, the developer discharge means can easily change the developer discharge amount as compared with the case where the developer discharge means does not set the width of the image to be narrower on the delivery end side than the other side.

  According to the invention described in claim 5, the developer discharging means discharges the developer without changing the width of the image as compared with the case where the density of the image is not set lower on the delivery end side than the other side. The amount can be changed.

  According to the invention described in claim 6, the developer discharging means forms a plurality of images at intervals along the conveyance direction of the recording medium, and the interval between the images on the delivery end side is wider than that on the other side. Compared to the case where the setting is not made, the developer discharge amount can be changed without changing the width and density of the image.

  According to the seventh aspect of the present invention, it is possible to avoid a decrease in the detection accuracy of the developer concentration even when the density detecting means is disposed on the delivery end side of the developing means.

  According to the eighth aspect of the present invention, it is possible to improve the stirring property of the developer as compared with the case where the supply port is disposed on the delivery end side of the developing means.

  According to the ninth aspect of the present invention, the image of each image forming unit is compared with the case where the amount of developer discharged by the developer discharging unit is not changed according to the image forming amount of each image forming unit. The developer can be discharged according to the formation amount.

1 is a schematic configuration diagram illustrating an image forming apparatus according to Embodiment 1 of the present invention. 1 is a configuration diagram illustrating an image forming unit of an image forming apparatus according to Embodiment 1 of the present invention; It is a schematic diagram which shows continuous paper. 1 is a block diagram showing a control device of an image forming apparatus according to Embodiment 1 of the present invention. 1 is a cross-sectional configuration diagram illustrating a developing device of an image forming apparatus according to Embodiment 1 of the present invention; It is a perspective block diagram which shows a developing device. It is a cross-sectional block diagram which shows a developing device. It is a cross-sectional block diagram which shows a developing device. It is a block diagram which shows the conventional image pattern. It is a block diagram which shows the image pattern of the image forming apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the image pattern of the image forming apparatus which concerns on Embodiment 1 of this invention. 1 is a configuration diagram illustrating a developing device of an image forming apparatus according to Embodiment 1 of the present invention.

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

[Embodiment 1]
1 and 2 show an image forming apparatus according to the first embodiment. FIG. 1 shows an outline of the whole image forming apparatus, and FIG.

<Overall Configuration of Image Forming Apparatus>
The image forming apparatus 1 according to the first embodiment is configured as a color printer, for example. The image forming apparatus 1 includes an image output apparatus 2 that forms an image using toners of four colors of yellow (Y), magenta (M), cyan (C), and black (K), and an example of a continuous recording medium. As a continuous paper 5, a paper discharge device 4 that discharges and stores the continuous paper 5 on which an image is formed by the image output device 2, and an upper portion of the paper discharge device 4. And a control device 100 that controls the output device 2, the paper feed device 3, and the paper discharge device 4. In the illustrated image forming apparatus 1, the paper feeding device 3, the paper discharging device 4, and the control device 100 are separately arranged outside the image output device 2. Of course, the apparatus 2, the paper feeding device 3, the paper ejection device 4, and at least a part of the control device 100 may be integrally arranged.

  The image output apparatus 2 includes an electrophotographic image forming unit 106 that forms an image on a continuous recording medium based on image data. The image forming unit 106 holds an image forming device 10 as an example of a plurality of image forming units that form toner images developed with toner constituting the developer, and a toner image formed by each image forming device 10. Then, an intermediate transfer device 20 that finally transports the continuous paper 5 to the secondary transfer position for secondary transfer, and a transport device 60 that transports the required continuous paper 5 to be supplied to the secondary transfer position of the intermediate transfer device 20. And a fixing device 40 as an example of a fixing unit including a heating step for fixing the toner image on the continuous paper 5 secondarily transferred by the intermediate transfer device 20.

  The image output device 2 can be configured as a color copying machine when an image reading device as an image reading unit (not shown) for inputting a document image to be formed on the continuous paper 5 is additionally provided. Reference numeral 2a in the figure denotes a housing of the image output apparatus 2, and the housing 2a is composed of a supporting component, an exterior cover, and the like.

  The image forming device 10 includes four image forming devices 10Y, 10M, 10C, and 10K that respectively form four color toner images exclusively for yellow (Y), magenta (M), cyan (C), and black (K). It is configured. These four image forming devices 10 (Y, M, C, K) are arranged in a line in the internal space of the housing 2a.

  As shown in FIG. 2, each image forming device 10 includes a photosensitive drum 11 as an example of a rotating image holding member, and the following devices are mainly disposed around the photosensitive drum 11. Is arranged. The main devices are a charging device 12 that charges a peripheral surface (image holding surface) on the photosensitive drum 11 on which an image can be formed to a required potential, and image information (on the charged peripheral surface of the photosensitive drum 11). The exposure device 13 as an electrostatic latent image forming unit that forms an electrostatic latent image (for each color) having a potential difference by irradiating light based on the signal), and the developer of the corresponding color A developing device 14 as an example of a developing unit that develops toner to form a toner image, a primary transfer device 15 that transfers each toner image to the intermediate transfer device 20, and an image holding surface of the photosensitive drum 11 after the primary transfer. A drum cleaning device 16 that removes and adheres toner and other adhering matter remaining on the drum.

  The photosensitive drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the peripheral surface of a cylindrical or columnar base material to be grounded. The photosensitive drum 11 is supported so as to rotate in a direction indicated by an arrow A when power is transmitted from a driving device (not shown).

  The charging device 12 is configured by a non-contact type charging device such as a corona discharger that is disposed without being in contact with the photosensitive drum 11. A charging voltage is supplied to the charging device 12. As the charging voltage, when the developing device 14 performs reversal development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied. Of course, a contact-type charging device such as a charging roll disposed in contact with the photosensitive drum 11 may be used as the charging device 12.

  The exposure device 13 forms an electrostatic latent image by irradiating the peripheral surface of the charged photosensitive drum 11 with light configured according to image information input to the image output device 2. Is. When the latent image is formed, the exposure device 13 receives information (signal) of an image that is input to the image output device 2 by any means and subjected to image processing by the image processing unit.

  In each of the developing devices 14, a developing roller 142 that holds the developer and conveys it to a developing region facing the photosensitive drum 11 inside the developing device main body in which an opening and a developer storage chamber are formed, and the developer. Agitation supply member 143 such as a screw auger and the agitation conveyance member 144 that convey the toner to be supplied to the developing roll 142 while stirring, and a layer thickness that regulates the amount (layer thickness) of the developer held on the developing roll 142 The restriction member 149 and the like are arranged. A developing bias voltage is supplied to the developing device 14 between the developing roll 142 and the photosensitive drum 11 from a power supply device (not shown). Further, the developing roll 142, the stirring supply member 143, and the stirring conveying member 144 are rotated in a required direction by receiving power from a rotation driving device (not shown). As the developer, for example, a two-component developer containing a nonmagnetic toner and a magnetic carrier is used. The configuration of the developing device will be described in detail later.

  In FIG. 1, reference numerals 160 (Y, M, C, and K) denote toner cartridges as developer containers that contain a developer containing at least toner to be supplied to the corresponding developing device 14. In this embodiment, toner in which a carrier is mixed is contained in the toner cartridge 160.

  The primary transfer device 15 is a contact-type transfer device including a primary transfer roll that rotates in contact with the peripheral surface of the photosensitive drum 11 and is supplied with a primary transfer voltage. As the primary transfer voltage, a DC voltage having a polarity opposite to the charging polarity of the toner is supplied from a power supply device (not shown).

  The drum cleaning device 16 is disposed so as to come into contact with the container-shaped main body, which is partially open, and the peripheral surface of the photosensitive drum 11 after the primary transfer at a required pressure, and removes adhered matters such as residual toner to clean the drum. And a collecting device for collecting deposits removed by the cleaning plate.

  As shown in FIGS. 1 and 2, the intermediate transfer device 20 is disposed so as to exist at a position below each image forming device 10 (Y, M, C, K). The intermediate transfer device 20 includes an intermediate transfer belt 21 that rotates in a direction indicated by an arrow B while passing a primary transfer position between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roll), and an intermediate transfer belt 21. A plurality of belt support rollers 22 to 24 that hold the toner in a desired state from the inner periphery thereof, and on the outer peripheral surface (image holding surface) side of the intermediate transfer belt 21 supported by the belt support roll 24. A secondary transfer device 30 that is disposed and secondary-transfers the toner image on the intermediate transfer belt 21 onto the continuous paper 5, and a toner that remains on the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30. The belt cleaning device 25 includes a blade-like cleaning member 26 that removes an adhering substance such as paper dust and cleans it.

  As the intermediate transfer belt 21, for example, an endless belt made of a material in which a resistance adjusting agent such as carbon black is dispersed in a synthetic resin such as polyimide resin or polyamide resin is used. The belt support roll 22 is configured as a drive roll, the belt support roll 23 is configured as a surface-exposing and tension applying roll of the intermediate transfer belt 21, and the belt support roll 24 is configured as a backup roll for secondary transfer. .

  As shown in FIG. 2, the secondary transfer device 30 is configured to move the intermediate transfer belt 21 at a secondary transfer position that is an outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roll 24 in the intermediate transfer device 20. The contact type transfer device includes a secondary transfer roll 31 that rotates in contact with a peripheral surface and is supplied with a secondary transfer voltage. The secondary transfer roll 31 or the belt support roll 24 of the intermediate transfer device 20 is supplied with a DC voltage having a polarity opposite or the same as the charging polarity of the toner as a secondary transfer voltage.

  As shown in FIG. 1, the fixing device 40 includes a roll-type or belt-type heating rotator 41 that is heated by heating means so that the surface temperature is maintained at a predetermined temperature, and the heating rotator. A roll-type or belt-type pressurizing rotator 42 rotating in contact with a required pressure at 41 is arranged. In the fixing device 40, the contact portion where the heating rotator 41 and the pressing rotator 42 come into contact becomes a fixing processing unit that performs a required fixing process (heating and pressing) including a heating process of heating the continuous paper 5. .

  By the way, the paper feeding device 3 includes a roll paper 61 in which a continuous long continuous paper 5 is wound in a roll shape as an example of a continuous recording medium, and supplies the continuous paper 5 from the roll paper 61. Further, the paper feeding device 3 is arranged in a state of being separated as a separate unit on the upstream side in the conveyance direction of the continuous paper 5 of the image output device 2. As the continuous paper 5, for example, as shown in FIG. 3, an adhesive or adhesive such as glue on a release paper 51 generally made of glassine paper that serves as a mount and is discarded when used. A surface substrate 53 made of a synthetic resin sheet such as PP (polypropylene) or PET (polyethylene terephthalate), or a paper such as fine paper or coated paper, is provided in the uppermost layer via an adhesive layer 52 as an intermediate layer made of A so-called label paper (hereinafter, continuous paper is also referred to as label paper) is used. The label paper 5 is used after the design and characters are printed on the surface of the surface base material 53. The label paper 5 is supplied as, for example, a roll paper 61 wound in a roll shape so that the surface base 53 side is positioned on the surface (outer peripheral surface) which is an image forming surface, depending on the application.

  The continuous recording medium is not limited to label paper, and may be continuous paper made of plain paper, continuous recording medium made of polyethylene film, or the like, and the type thereof is not limited.

  As shown in FIG. 1, the paper feeding device 3 applies tension to the roll paper 61 that is rotated in the clockwise direction by a driving unit (not shown) and the label paper 5 that is fed along with the rotation of the roll paper 61. A tension applying unit 62 is provided. The tension applying unit 62 includes transport rollers 62a and 62b that transport the label paper 5, and a tension roller 62c that is provided with an elastic force in a direction away from the transport rollers 62a and 62b.

  The image output device 2 includes a transport device 60 that transports the label paper 5 fed from the paper feed device 3 to the secondary transfer position inside the housing 2a. The transport device 60 includes a transport roll 63 that transports the label paper 5 in contact with the surface opposite to the image forming surface (the back surface in the illustrated example). The transport device 60 includes a pair of transport rolls that transport the label paper 5 sandwiched therebetween, and a discharge roll (not shown) that discharges the label paper 5 disposed on the downstream side of the fixing device 40 and having an image formed thereon. You may comprise as follows. Further, the transport device 60 may be any device that can transport the label paper 5 as a continuous recording medium, and includes tension applying units 62 and 64 disposed inside the paper feeding device 3 and the paper discharge device 4, and a recording device. You may comprise so that the conveyance roll etc. which are not shown in figure which change the conveyance direction of the label paper 5 as a medium may be included.

  Further, on the downstream side of the image output device 2, a paper discharge device 4 that discharges and stores the label paper 5 on which an image is formed by the image output device 2 is disposed. The paper discharge device 4 includes a tension applying unit 64 that applies tension to the label paper 5 and a take-up roll 65 that is arranged to be rotatable in the clockwise direction in the drawing and winds the label paper 5 in a roll shape. The tension applying unit 64 includes transport rolls 64a and 64b that transport the label paper 5, and a tension imparting roll 64c that is provided with an elastic force in a direction away from the transport rolls 64a and 64b. Note that a cutting device 66 for cutting the label paper 5 may be disposed at the entrance of the paper discharge device 4 as necessary.

  FIG. 4 shows a control device that controls the operation of the image forming apparatus.

  In FIG. 4, reference numeral 100 indicates a control device that comprehensively controls the operation of the image forming apparatus 1. The control device 100 includes a CPU 101 (Central Processing Unit) that centrally controls the operation of the image forming apparatus 1, a ROM 102 (Read Only Memory) that stores a program executed by the CPU 101, and a RAM 103 that temporarily stores control parameters and the like. (Random Access Memory), or a bus for connecting the CPU 101 and the ROM 102, a communication interface, and the like.

  Further, the control device 100 forms an image in the non-image area at both ends along the direction intersecting the conveyance direction of the continuous paper 5 of each photosensitive drum 11 in the image forming unit 106, and supplies toner as a developer. Controls the toner discharge operation. Therefore, the control device 100 determines the image forming devices 10Y and 10M for yellow (Y), magenta (M), cyan (C), and black (K) of the image forming unit 106 based on the control information of the image forming unit 106. , 10C and 10K, the number of pixels or image density (area coverage) output to the exposure device 13 corresponding to the toner discharge amount is counted, and the degree of deterioration of the developer 4 accommodated in the developing device 14 is determined.

  Reference numeral 104 denotes a user interface unit for inputting and displaying the type and size of a recording medium including a label sheet 5 on which an image is formed, or the number of prints, 105 denotes an image input device, and 106 denotes development of the image output device 2. An image forming unit 107 also has a function as an agent discharging unit, and an image storage unit 107 stores image information (image pattern) for discharging the developer in the image forming unit 106. Note that the image storage unit 107 may be replaced by the ROM 102 that stores image information for discharging the developer in the image forming unit 106.

<Basic operation of image forming apparatus>
Hereinafter, a basic image forming operation by the image output apparatus 2 of the image forming apparatus 1 will be described.

  Here, a full-color image constituted by combining four color (Y, M, C, K) toner images using the four image forming devices 10 (Y, M, C, K) of the image output device 2. An image forming operation when forming the image will be described. The four image forming devices 10 (Y, M, C, K) of the image output device 2 are used to form a toner image of one or more of the four colors (Y, M, C, K). The image forming operation when doing this is the same.

  When the image output device 2 receives the command information of the request for the image forming operation (printing), the image forming device 10 (Y, M, C, K), the intermediate transfer device 20, the secondary transfer device 30, and the fixing device. 40 etc. starts.

  In each imaging device 10 (Y, M, C, K), as shown in FIG. 2, first, each photosensitive drum 11 is rotated in the direction indicated by arrow A, and each charging device 12 is moved to each photosensitive device. The surface of the body drum 11 is charged to a required polarity (negative polarity in the first embodiment) and potential. Subsequently, an image obtained by the exposure device 13 converting the information of the image input to the image output device 2 into each color component (Y, M, C, K) on the surface of the photosensitive drum 11 after charging. The light emitted on the basis of the signal is irradiated to form an electrostatic latent image of each color component composed of a required potential difference on the surface.

  Subsequently, each developing device 14 (Y, M, C, K) has a corresponding color charged with a required polarity (minus polarity) with respect to the electrostatic latent image of each color component formed on the photosensitive drum 11. (Y, M, C, K) toners are respectively supplied and electrostatically adhered to perform development. By this development, the electrostatic latent images of the respective color components formed on the respective photosensitive drums 11 are visualized as toner images of four colors (Y, M, C, K) respectively developed with the corresponding color toners. It becomes.

  Subsequently, when each color toner image formed on the photosensitive drum 11 of each image forming device 10 (Y, M, C, K) is conveyed to the primary transfer position, the primary transfer device 15 causes each color image. The toner image is primarily transferred in such a manner that the toner image is sequentially superimposed on the intermediate transfer belt 21 rotating in the direction indicated by the arrow B of the intermediate transfer device 20.

  Further, in each image forming apparatus 10 for which the primary transfer has been completed, the drum cleaning device 16 cleans the surface of the photosensitive drum 11 by removing the adhering matter such as toner remaining on the surface of the photosensitive drum 11 so as to scrape off. . Thereby, each image forming apparatus 10 is brought into a state in which the next image forming operation can be performed.

  Subsequently, in the intermediate transfer device 20, the toner image primarily transferred by the rotation of the intermediate transfer belt 21 is held and conveyed to the secondary transfer position. On the other hand, in the paper feed device 3 and the paper discharge device 4, the label paper 5 is introduced from the paper feed device 3 into the housing 2 a of the image output device 2 prior to the image forming operation, and the transport roll 63 of the transport device 60. From the secondary transfer position and the fixing device 40, the leading end of the label paper 5 is wound around the take-up roll 65 via the tension applying portion 64 of the paper discharge device 4. At the time of image formation, the label paper 5 fed from the paper feeding device 3 is transported through the image output device 2 at a required transport speed and then accommodated in the paper discharge device 4.

  At the secondary transfer position, the secondary transfer device 30 collectively transfers the toner image on the intermediate transfer belt 21 onto the label paper 5. Further, in the intermediate transfer device 20 after the secondary transfer is completed, the belt cleaning device 25 removes and removes adherents such as toner remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

  Subsequently, the label paper 5 on which the toner image is secondarily transferred is peeled from the intermediate transfer belt 21 and the secondary transfer roll 30 and then conveyed to the fixing device 40. In the fixing device 40, necessary fixing processing (heating and pressing) is performed to fix the unfixed toner image on the label paper 5. Finally, the label paper 5 after fixing is discharged to the outside of the image output apparatus 2 and taken up by a take-up roll 65 provided inside the paper discharge apparatus 4.

  Through the above operation, the label paper 5 on which a full color image formed by combining four color toner images is output.

<Configuration of developing device>
5A and 5B are cross-sectional configuration diagrams showing developing devices in the respective image forming apparatuses 10 (Y, M, C, K) used in the image forming apparatus according to the first embodiment. 5A is a cross-sectional view taken along the line Va-Va in FIG. 7 described later, and FIG. 5B is a cross-sectional view taken along the line Vb-Vb in FIG. 7 described later.

  As shown in FIG. 5, the developing device 14 is disposed so as to face the photosensitive drum 11 in the developing region. The developing device 14 includes a developing device main body 140 as an example of a developer container. Inside the developing device main body 140, a two-component developer 4 composed of a negatively chargeable toner and a positively chargeable magnetic carrier is accommodated.

  As shown in FIG. 6, the developing device main body 140 is formed as a substantially rectangular parallelepiped box extending in the front-rear direction along the axial direction of the photosensitive drum 11. As shown in FIG. 5, the developing device main body 140 has an opening 141 at a portion facing the photosensitive drum 11. A developing roll 142 as an example of a developer holding member is rotatably disposed in the opening 141 of the developing device main body 140. The developing roll 142 includes a magnet roll 142a as an example of a magnetic field generating member and a developing sleeve 142b as an example of a rotating member that covers the outer peripheral surface of the magnet roll 142a. Inside the developing device main body 140, on the back side of the developing roll 142, a stirring supply member 143 made of a screw auger or the like as an example of a supplying member at substantially the same height as the developing roll 142 or slightly lower than the developing roll 142 is provided. Is arranged to be rotatable. Further, below the stirring supply member 143 along the vertical direction (directly below), a stirring and conveying member 144 including a screw auger as an example of a conveying member is rotatably disposed. In the developing device 14 according to this embodiment, a staying conveyance member 145 including a screw auger as an example of an auxiliary conveyance member having a diameter smaller than that of the agitation conveyance member 144 is disposed between the developing roll 142 and the agitation conveyance member 144. ing. The stay conveyance member 145 is not necessarily provided.

  A partition wall 146 is provided between the stirring supply member 143 and the stirring transport member 144. For example, the partition wall 146 is formed integrally with a part of the developing device main body 140. The partition wall 146 has an arcuate curved surface portion along the outer peripheral surface of the stirring supply member 143 on the upper end surface thereof. The partition wall 146 partitions the inside of the developing device main body 140 into upper and lower transport areas 140a and 140b. As will be described later, communication ports 147 and 148 (see FIG. 7) as an example of a delivery unit for delivering the developer 4 by connecting upper and lower transport regions 140a and 140b to the front end and the rear end of the partition wall 146. And FIG. 8) are opened. The developer 4 accommodated in the developing device main body 140 is conveyed so as to circulate up and down through the communication ports 147 and 148 while being agitated along the axial direction by the agitation supply member 143 and the agitation conveyance member 144. The developer 4 is supplied to the developing roll 142 via the stay conveyance member 145 or directly while being conveyed by the stirring supply member 143. In the developer 4 supplied to the developing roll 142, the amount (layer thickness) of the developer 4 held on the developing roll 142 is regulated by the layer thickness regulating member 149. The stay conveyance member 145 is a member for conveying the developer 4 supplied from the stirring supply member 143 along the axial direction of the developing roll 142 while retaining the developer 4 between the stirring supply member 143 and the developing roll 142. is there.

  The agitation supply member 143 and the agitation conveyance member 144 are set to have a longer length in the axial direction than the development roll 142 in order to convey and supply the developer 4 to the development roll 142 while stirring the developer 4 uniformly.

  More specifically, in the developing device main body 140, as shown in FIG. 6, the length of the developing roll 142 along the axial direction is set to a length substantially corresponding to the developing roll 142. On the other hand, the stirring supply member 143 and the stirring transport member 144 are longer than the developing roll 142. Both ends of the agitation supply member 143 and the agitation transport member 144 along the axial direction protrude from the developing device main body 140 in the front-rear direction. The developing device main body 140 includes a cylindrical front side covering member 151 and a rear side covering member 152 that are connected vertically to cover both ends of the stirring supply member 143 and the stirring conveyance member 144 along the front-rear direction. For example, the front side covering member 151 and the rear side covering member 152 are provided integrally or separately from the side walls disposed before and after the developing device main body 140.

  As shown in FIGS. 6 and 7, the front covering member 151 is formed in a shape in which two cylindrical members 151 a and 151 b are integrally connected vertically. Inside the front covering member 151, cylindrical accommodating portions 151c and 151d that rotatably accommodate and support the front end portions of the stirring supply member 143 and the stirring and conveying member 144 are provided. The insides of the cylindrical accommodating portions 151c and 151d communicate with the developing device main body 140. Further, the end portion of the front covering member 151 is closed. The cylindrical accommodating portions 151c and 151d are partitioned vertically by a partition wall 146. As described above, the partition wall 146 has a communication port 147 that transfers the developer 4 conveyed by the agitation supply member 143 to the agitation conveyance member 144.

  Further, as shown in FIG. 7, a supply port 153 for supplying a new developer from a developer supply device (not shown) is opened on the upper end surface of the end portion along the axial direction of the front covering member 151. Yes. The supply port 153 is disposed on the side opposite to the delivery end side that delivers the developer 4 from the stirring supply member 143 to the stirring and conveying member 144. The supply port 153 is connected to a cylindrical member 154 that conveys the developer supplied from a developer supply device (not shown). The stirring supply member 143 is provided with a spiral stirring member 155 that unwinds the developer supplied from the supply port 153. The supply port 153 is arranged so that the position thereof partially overlaps with the communication port 147 of the partition wall 146 in the vertical direction. The conveying blade 143a of the stirring supply member 143 is provided up to a position corresponding to the communication port 147 along the developer conveying direction. The developer supplied from the supply port 153 is immediately transferred to the agitating / conveying member 144 via the communication port 147 and conveyed to the inside of the developing device main body 140 by the agitating / conveying member 144. The stirring conveyance member 144 is provided with a conveyance blade 144 a from the upstream side of the communication port 147.

  On the other hand, as shown in FIG. 8, the rear covering member 152 is formed in a shape in which two cylindrical members 152 a and 152 b are integrally connected to each other in the same manner as the front covering member 151. In this embodiment, the length of the rear covering member 152 along the axial direction is set shorter than that of the front covering member 151. However, the rear covering member 152 may of course be set to have the same length as the front covering member 151. Inside the rear covering member 152, cylindrical accommodating portions 152c and 152d that rotatably accommodate rear end portions of the agitation supply member 143 and the agitation transport member 144 are provided. Further, the end portion of the rear covering member 152 is closed. At the end of the rear covering member 152, the rotating shafts 143b and 144b of the stirring supply member 143 and the stirring and conveying member 144 are rotatably supported through a bearing member in a state of projecting to the outside. Cylindrical accommodating parts 152c and 152d are partitioned vertically by a partition wall 146. As described above, the partition wall 146 has a communication port 148 that transfers the developer 4 conveyed by the agitation conveyance member 144 to the agitation supply member 143. The direction in which the agitation transport member 144 delivers the developer to the agitation supply member 143 is upward along the vertical direction as indicated by an arrow in FIG. In FIG. 8, reference numeral 161 denotes a density sensor as an example of density detecting means for detecting the toner density of the developer 4 contained in the developing device main body 140. The density sensor 161 is disposed on the delivery end side for delivering the developer 4 from the stirring / conveying member 144 of the developing device main body 140 to the stirring supply member 143. The control device 100 replenishes the developer 4 inside the developing device main body 140 at a required timing based on the detection result of the density sensor 161.

  At the downstream end along the axial direction (conveying direction) of the agitating / conveying member 144, the developer 4 conveyed by the agitating / conveying member 144 is transferred to the agitation supply member 143 through the communication port 148. A short reverse conveying blade 144e is provided. The reverse conveyance blade 144 e conveys the developer 4 in the direction opposite to the conveyance direction of the stirring conveyance member 144. The developer 4 conveyed to the vicinity of the end along the axial direction by the agitating / conveying member 144 is conveyed in the reverse direction by the reverse conveying blade 144e and combined with the developer 4 conveyed by the normal conveying blade 144a, the partition wall 146 It is conveyed and delivered to the stirring supply member 143 located in the upper direction along the vertical direction through the communication port 148 opened in the upper part.

  Further, as shown in FIG. 7, a discharge port 156 for discharging excess developer is opened in the front cover member 151. As shown in FIG. 6, the excess developer discharged from the discharge port 156 is one end portion along the longitudinal direction of the developing device main body 140 via a conveying member 157 arranged on the back side of the developing device main body 140. Is transported to and recovered by a recovery unit 158 provided in

  At the rear end of the developing device main body 140, as shown in FIG. 6, driving for rotationally driving the developing roll 142, the agitation supply member 143, the agitation conveyance member 144, the stay conveyance member 145, and the conveyance member 157 A plurality of gears 159a to 159f are provided as an example of force transmission means.

<Configuration of Characteristic Part of Image Forming Apparatus>
By the way, in the image forming apparatus 1 according to the first embodiment, when the toner in the developer 4 stored in the developing device 14 (Y, M, C, K) deteriorates, the charging characteristics change, and the image quality is improved. There is a risk of affecting.

  More specifically, in the image forming apparatus 1, the toner of the developer 4 accommodated in each developing device 14 is consumed when an image is formed on the continuous paper 5. In the image forming apparatus 1, when an image having a relatively high density is formed on the continuous paper 5, the toner in the developer 4 accommodated in each developing device 14 is consumed, and a required amount is contained in the developing device 14. A new developer is supplied at the timing.

  However, in the image forming apparatus 1, the toner in any one or more of the developing devices 14 (Y, M, C, K) is used when continuously forming relatively low density images on the continuous paper 5. There is a case where almost no new developer is supplied to the inside of the developing device 14 because it is hardly consumed. Then, inside the developing device 14, the developer 4 is conveyed while being stirred so as to be repeatedly circulated by the stirring supply member 143 and the stirring and conveying member 144. When the developer 4 is repeatedly circulated and transported inside the developing device main body 140, the chargeability and release properties added to the surface of the toner when the toner in the developer 4 is stirred and transported with a carrier or the like. The external additive for adjusting the properties may be peeled off by being rubbed with the carrier or the toner, or may be deteriorated by being embedded in the toner. In the developing device 14, when the toner deteriorates, the charging characteristics and the like may change, and the developing performance may deteriorate.

  As shown in FIG. 7, the developing device 14 includes a mechanism for discharging the deteriorated developer 4 to the outside. However, in a state where the developer 4 in the developing device main body 140 is hardly consumed, the mechanism for discharging the developer 4 to the outside is also difficult to function sufficiently.

  In an image forming apparatus that forms an image on each cut sheet, toner is forcibly formed by forming a predetermined belt-like image pattern or the like on the intermediate transfer belt at a timing when image formation between sheets is not performed. It is possible to prevent or suppress toner deterioration by discharging the toner. However, as described above, in the image forming apparatus 1 that forms an image on the continuous paper 5, there is no region for forming a belt-like image pattern between the images, and thus the toner cannot be discharged.

  Therefore, in the image forming apparatus 1, as shown in FIG. 9, the image 200 based on the image information is formed in the image area, and at the same time, the image set in advance in the predetermined side area of the continuous paper 5 outside the image area. It has been proposed to provide developer discharging means for discharging toner to an area other than the image on the continuous paper 5 by forming the pattern 201 to promote toner circulation and suppress toner deterioration. The image pattern 201 discharges the toner and promotes the circulation of the toner, and is formed at a relatively high density (for example, a density of 100%).

  However, in such an image forming apparatus 1, when the belt-shaped image pattern 201 is formed at both ends along the direction (width direction) intersecting the conveyance direction of the continuous paper 5 and the toner is discharged, the following technical matters are obtained. It has been clarified by the present inventors that problems arise.

  As shown in FIG. 5, the developing device 14 used in the image forming apparatus 1 includes a stirring supply member 143 that transports the developer 4 so as to circulate in the developing device main body 140 and a stirring transport member 144 in the vertical direction. It is arranged up and down along. Therefore, among the end portions on the delivery side that delivers the developer 4 between the agitation supply member 143 and the agitation conveyance member 144, as shown in FIG. 8, the agitation conveyance member disposed below in the vertical direction At the end on the communication port 148 side, which is the delivery end side that delivers the developer 4 to the stirring supply member 143 disposed above the vertical direction from 144, the developer is supplied to the stirring supply member 143 via the communication port 148. As shown in FIG. 5A, the developer 4 is immediately supplied to the developing roll 142 by the stirring supply member 143 and used for development. As a result, at the end of the developing device 14 on the side of the communication port 148, the developer 4 whose toner density has been reduced by developing the image pattern 201 with a relatively high image density is discharged to the developing roll 142 as it is. Therefore, there is a possibility that the image density is lowered.

  On the other hand, at the end of the developing device 14 on the communication port 147 side, the developer 4 whose image density has been reduced by developing the image pattern 201 is transferred to the agitating and conveying member 144 and conveyed by the agitating and conveying member 144. Since the developer 4 accommodated in the developing device main body 140 is agitated during this time, the developer 4 is not immediately supplied to the developing roll 142 and hardly affects the image density.

  Further, although the agitation supply member 143 is separated from the agitation transport member 144 by the partition wall 146, there is a gap on the developing roll 142 side of the agitation supply member 143. Therefore, the developer 4 conveyed to the agitation supply member 143 is conveyed by the agitation supply member 143 and the stay conveyance member 145, but is not conveyed to the end portion along the axial direction of the agitation supply member 143. A part of the developer 4 transported by the stirring supply member 143 may fall downward from the gap between the partition wall 146 and the developing roll 142 and be transported to the stirring transport member 144 as it is. The developer 4 dropped downward from the gap between the partition wall 146 and the developing roll 142 and conveyed to the stirring and conveying member 144 as it is is sufficiently stirred with the developer 4 accommodated inside the developing device main body 140. Instead, it is conveyed again from the communication port 148 to the stirring supply member 143.

  As a result, at the end of the stirring supply member 143 on the side of the communication port 148, the developer 4 whose toner concentration has been reduced by the development of the image pattern 201 is supplied as it is to the developing roll 142 as well as the partition wall 146 and the developing roll 142. There is a tendency that the developer 4 having a low toner concentration that has dropped downward from the gap is supplied to the stirring supply member 143 as it is. Therefore, in the developing device 14, the density of the original image 200 to be formed on the continuous paper 5 at the end on the communication port 148 side is greatly reduced, and there is a possibility that the image quality is lowered.

  Therefore, in this embodiment, as shown in FIG. 10, the control device 100 controls each image forming device 10 (Y, M, C, K) of the image forming unit 106 to form an image pattern 201. When the toner is discharged, the toner discharge amount on the communication port 148 side, which is the delivery end side of the stirring supply member 143 of the developing device 14, is configured to be smaller than that on the other side. Here, the toner discharge amount on the communication port 148 side which is the delivery end side is smaller than that on the other side includes the case where the image pattern 201 is not formed on the delivery end side.

  Specifically, in the image forming apparatus 1 according to this embodiment, as shown in FIG. 10, the line width W1 of the belt-like image pattern 201 formed on the delivery end side of the stirring supply member 143 of the developing device 14 is set. The line width W2 on the communication port 147 side, which is the other side, is set narrower (W1 <W2). Here, the density of the image pattern 201 is not changed.

  When the control device 100 controls the image forming unit 106 to form the belt-shaped image pattern 201 at both ends along the direction intersecting the conveyance direction of the continuous paper 5, the control device 100 stores the image in the image storage unit 107. Based on the image information for forming the image pattern 201, the line width W1 of the strip-shaped image pattern 201 formed on the delivery end side of the stirring supply member 143 of the developing device 14 is set to the line on the communication port 147 side which is the other side. Control is made to be narrower than the width W2.

  The belt-like image pattern 201 formed by the image forming unit 106 is transferred to the intermediate transfer belt 21 at the secondary transfer position, and transferred to the continuous paper 5 as it is.

<Operation of Characteristic Part of Image Forming Apparatus>
In the image forming apparatus 1 according to the first embodiment, when the toner in the developer 4 accommodated in the developing device 14 (Y, M, C, K) deteriorates, the charging characteristics change, which affects the image quality. There is a risk of effect.

  In the image forming apparatus 1 according to the first embodiment, the control device 100 includes the yellow (Y), magenta (M), cyan (C), and black (K) image forming devices 10Y and 10M of the image forming unit 106. , 10C and 10K, the number of pixels or image density (area coverage) output to the exposure device 13 corresponding to the toner discharge amount is counted, and the number of pixels or image density (area coverage) output to the exposure device 13 is required. It is determined whether it is below the threshold value.

  When the control device 100 determines that the number of pixels or the image density (area coverage) output to the exposure device 13 in each of the image forming devices 10Y, 10M, 10C, and 10K is equal to or less than a predetermined threshold, as shown in FIG. In addition, the image 200 to be transferred to the continuous paper 5 is formed, and at the same time, the image pattern 201 is formed at the required image density (for example, 100%) at both ends along the direction intersecting the conveyance direction of the continuous paper 5.

  At this time, the control device 100 sets the line width W1 of the strip-shaped image pattern 201 formed on the communication port 148 side which is the delivery end side of the stirring supply member 143 in the developing device 14 of the continuous paper 5 to the communication port which is the other side. Control is made to be narrower than the line width W2 on the 147 side.

  Therefore, in the developing device 14, as shown in FIGS. 5A and 8, a belt-like image pattern is formed at the end on the communication port 148 side, which is the delivery end side for delivering the developer 4 to the stirring supply member 143. The developer 4 whose toner density is reduced by developing 201 is supplied to the agitation supply member 143 through the communication port 148. However, the line width W1 of the strip-shaped image pattern 201 at the end on the communication port 148 side is Since the line width W2 on the side of the communication port 147 is set to be narrower, the degree of decrease in the toner density is reduced from the other side.

  As a result, at the end of the developing device 14 on the communication port 148 side, a decrease in toner density due to the development of the image pattern 201 is suppressed, and a decrease in image density is prevented or suppressed. This is the case where the developer 4 dropped downward from the gap between the partition wall 146 and the developing roll 142 at the end of the stirring supply member 143 on the communication port 148 side is supplied to the stirring supply member 143 as it is. But the same is true.

  Further, in this embodiment, even when the density sensor 161 is disposed on the delivery end side of the developing device 14, a decrease in toner density due to development of the image pattern 201 on the delivery end side is suppressed, and development is performed. It can be avoided that the detection accuracy of the toner concentration of the agent 4 is lowered.

  Further, in this embodiment, since the supply port 153 for the new developer 4 is disposed at the end portion on the side of the communication port 147 opposite to the delivery end side of the developing device 14, the line width is relatively large. Even when the image pattern 201 having a wide W2 is developed and the toner density is lowered, the developer can be sufficiently stirred with the new developer 4 while being transported by the stirring and transporting member 144. Can be improved.

[Embodiment 2]
FIG. 11 shows an image forming apparatus according to Embodiment 2 of the present invention.

  In the image forming apparatus 1 according to the second embodiment, as shown in FIG. 11, the configuration of the image pattern is different from that of the first embodiment. That is, in the second embodiment, as shown in FIG. 11A, the density D1 of the band-shaped image pattern 201 at the end on the communication port 148 side is the band at the end on the other side of the communication port 147. The image pattern 201 is set to be lower than the density D2. The density D1 of the strip-shaped image pattern 201 at the end on the communication port 148 side is set to about 30 to 40%, for example. On the other hand, the density D2 of the band-shaped image pattern 201 at the end on the other side of the communication port 147 side is set to about 100%, for example.

  FIG. 11B shows a modification of the image pattern. The image pattern 201 is not a strip-shaped image continuous along the transport direction of the continuous paper 5, but is not a strip-shaped image continuous along the transport direction of the continuous paper 5, but is spaced along the transport direction of the continuous paper 5. The interval between the images G1 on the delivery end side is set wider than the interval G2 on the other side.

[Embodiment 3]
FIG. 12 shows an image forming apparatus according to Embodiment 3 of the present invention.

  In the image forming apparatus 1 according to the third embodiment, as illustrated in FIG. 12, the developing device does not include the stay conveyance member, and the developer 4 is directly supplied from the stirring supply member 143 to the developing roll 142. It is configured.

  In the third embodiment, the partition wall 146 is arranged to extend to the vicinity of the developing roll 142, but the developer 4 whose toner density is reduced by forming the image pattern 201 is directly supplied to the developing roll 142. However, the image density at the end of the stirring supply member 143 on the communication port 148 side is lowered. Also in the developing device 14, the low-concentration developer 4 that has dropped downward from the gap between the partition wall 146 and the developing roll 142 is supplied to the stirring supply member 143 as it is. Therefore, the developing device 14 has a technical problem that the density of the original image to be formed on the continuous paper 5 is greatly reduced, and the image quality is lowered.

  Therefore, the third embodiment is configured to form an image pattern 201 as in the first embodiment described above.

  In the above embodiment, a full-color image forming apparatus that forms toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K) has been described as the image forming apparatus. Needless to say, the present invention can be similarly applied to an image forming apparatus that forms the image.

  In the above-described embodiment, the image forming apparatus including the intermediate transfer device has been described. However, the image forming apparatus is not limited thereto, and may be an image forming apparatus that directly transfers from a photosensitive member to a sheet.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 1a ... Image forming apparatus main body 10 ... Image forming apparatus 11 ... Photoconductor drum 14 ... Developing apparatus 100 ... Control apparatus

Claims (9)

A developing unit having a supply member for supplying a developer composed of toner and a carrier to the developer holding member and a conveying member for conveying the developer peeled off from the developer holding member and delivering the developer to the supply member at a delivery end; Image forming means for forming an image by transferring an image obtained by developing a latent image on an image carrier onto a continuous recording medium;
A means for forming an image in a non-image area at both ends along a direction intersecting the conveyance direction of the recording medium of the image carrier and discharging the toner, and a discharge amount on the delivery end side of the developing means is Less developer discharge means than the other side;
An image forming apparatus.   The image forming apparatus according to claim 1, wherein the developing unit has the supply member disposed above the conveying member in a vertical direction.   The image forming apparatus according to claim 2, wherein the delivery end side of the developing unit is a conveyance start end side of the supply member.   The image forming apparatus according to claim 1, wherein the developer discharging unit sets a width of the image on the delivery end side to be narrower than that on the other side.   The image forming apparatus according to claim 1, wherein the developer discharging unit sets a density of the image on the delivery end side to be lower than that on the other side.   2. The developer discharge unit according to claim 1, wherein the developer discharging unit forms a plurality of images at intervals along a conveyance direction of the recording medium, and sets the interval between the images on the delivery end side wider than that on the other side. Image forming apparatus. The developing means includes a density detecting means for detecting the toner density in the developer contained in the developing means,
The image forming apparatus according to claim 1, wherein the density detecting unit is disposed on the delivery end side of the developing unit. The developing means has a supply port for supplying a new developer to the upstream end of the transport member along the transport direction of the developer,
The image forming apparatus according to claim 1, wherein the supply port is disposed on a side opposite to the delivery end side of the developing unit. A plurality of image forming means for forming different images from each other,
9. The image forming apparatus according to claim 1, wherein the amount of developer discharged by the developer discharging unit varies according to the image forming amount of each of the image forming units.

Images