Image forming apparatus

Abstract

To provide an image forming apparatus that can prevent scattering of toner when developing an electrostatic latent image with the toner.SOLUTION: An image forming apparatus comprises an attachment part, an image forming unit 11, a feed passage 210, a toner charging unit 200, a detection unit 104, and a control unit 20. A toner container 116 storing toner is removably attached to the attachment part. The image forming unit 11 forms an image on a sheet by using the toner. The feed passage 210 feeds the toner from the toner container 116 to the image forming unit 11. The toner charging unit 200 electrically charges the toner passing through the feed passage 210. The detection unit 104 detects environment information. The control unit 20 controls the toner charging unit 200 on the basis of the environment information.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] The developing device described in Patent Document 1 includes a developer carrier, a casing, and an electrode. The developer carrier is made up of a base that holds and moves the developer on its surface side, and a magnetic body that is fixedly disposed inside the base and has a plurality of magnetic poles. The casing holds the developer carrier. The electrode is disposed in the casing facing the developer carrier. The electrode is disposed at a position including an area where the change in magnetic flux density in the normal direction formed by a predetermined magnetic pole of the magnetic body is approximately maximum. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-66886 A Summary of the Invention [Problem to be solved by the invention]

[0004] The developing device described in Patent Document 1 can prevent toner charged with a polarity opposite to the set polarity from scattering when developing an electrostatic latent image with toner, but cannot prevent toner with a low charge from scattering.

[0005] The present invention has been made in view of the above problems, and has an object to provide an image forming apparatus capable of suppressing toner scattering when developing an electrostatic latent image with toner. [Means for solving the problem]

[0006] According to one aspect of the present invention, an image forming apparatus includes an attachment unit, an image forming unit, a supply path, a toner charging unit, a detection unit, and a control unit. A toner container containing toner is removably attached to the attachment unit. The image forming unit forms an image on a sheet using the toner. The supply path supplies the toner from the toner container to the image forming unit. The toner charging unit charges the toner passing through the supply path. The detection unit detects environmental information. The control unit controls the toner charging unit based on the environmental information. Effect of the Invention

[0007] According to the image forming apparatus of the present invention, scattering of toner can be suppressed when developing an electrostatic latent image with toner. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view illustrating an example of a configuration of an image forming unit according to the present embodiment. [Diagram 3] 1 is a block diagram showing a configuration of an image forming apparatus according to an embodiment of the present invention; [Figure 4] 6 is a flowchart illustrating an example of a process of a control unit according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference characters and the description will not be repeated. In the embodiment, the X-axis and the Y-axis are horizontal, the Z-axis is vertical, and the X-axis, the Y-axis, and the Z-axis are mutually orthogonal.

[0010] First, a configuration of an image forming apparatus 100 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of the image forming apparatus 100. As shown in Fig. 1, the image forming apparatus 100 is, for example, a color multifunction peripheral.

[0011] The image forming apparatus 100 includes an image forming unit 10, a feeding section 30, a conveying section 40, a fixing section 50, a discharging section 60, a control section 20, a memory section 80, an operation section 120, a document feeding section 90, a scanner section 91 and a detection section 104.

[0012] The document feeder 90 includes a document placement unit 90a. The document feeder 90 transports the document G set on the document placement unit 90a to a reading position of the scanner unit 91.

[0013] The scanner unit 91 illuminates the document G with an exposure lamp and receives the reflected light with a CCD (Charge Coupled Device), thereby reading an image from the document G and generating image data representing the image. The image data includes, for example, a plurality of pixel data each of which indicates a plurality of gradation values. The scanner unit 91 then outputs the image data to the control unit 20.

[0014] The feeding section 30 supplies the sheet P to the conveying section 40. The conveying section 40 conveys the sheet P to the discharge section 60 via the image forming unit 10 and the fixing section 50. The sheet P is, for example, plain paper, copy paper, recycled paper, thin paper, thick paper, glossy paper, or OHP (Overhead Projector).

[0015] The image forming unit 10 forms an image on a sheet P based on image data. The fixing section 50 heats and pressurizes the sheet P, and fixes the toner image transferred to the sheet P to the sheet P. The discharge section 60 discharges the sheet P to the outside of the image forming apparatus 100.

[0016] The detection unit 104 detects environmental information. The environmental information includes information indicating temperature and humidity.

[0017] The control unit 20 controls the image forming unit 10, the feeding unit 30, the conveying unit 40, the fixing unit 50, the discharging unit 60, the document feeding unit 90, the scanner unit 91, and the detection unit 104. Specifically, the control unit 20 includes a processor such as a CPU (Central Processing Unit).

[0018] The storage unit 80 includes a storage device and stores a computer program. Specifically, the storage unit 80 includes a main storage device such as a semiconductor memory, and an auxiliary storage device such as a semiconductor memory and / or a hard disk drive.

[0019] The operation unit 120 includes a display unit and an operation key unit. The display unit is, for example, a liquid crystal display. The display unit displays image information. The display unit also functions as a touch panel for input.

[0020] Next, a description will be given of the configuration of the image forming unit 10. The image forming unit 10 includes a plurality of image forming sections 11, a plurality of mounting sections 19, an exposure section 13, and a transfer section 12. That is, there are a plurality of image forming sections 11 and mounting sections 19.

[0021] A toner container is detachably attached to each of the multiple mounting portions 19. The toner container contains toner. The toner contains a large number of toner particles. The particle size of the toner particles is, for example, 5.0 μm or more and 8.0 μm or less, and preferably 5.2 μm or more and 6.7 μm or less, in terms of volume-based median diameter (D50). For example, the multiple toner containers include a toner container that contains cyan toner, a toner container that contains magenta toner, a toner container that contains yellow toner, and a toner container that contains black toner.

[0022] Toner is supplied to the multiple image forming units 11. Each of the multiple image forming units 11 includes a photoconductor drum 101. For example, the multiple image forming units 11 include image forming unit 11c to which cyan toner is supplied, image forming unit 11m to which magenta toner is supplied, image forming unit 11y to which yellow toner is supplied, and image forming unit 11k to which black toner is supplied. The image forming units 11c, 11m, 11y, and 11k have substantially the same configurations.

[0023] The exposure unit 13 irradiates each of the multiple photoconductor drums 101 with laser light. As a result, an electrostatic latent image is formed on each of the multiple photoconductor drums 101. Then, the multiple image forming units 11 each develop the multiple electrostatic latent images. The multiple electrostatic latent images are each developed with toner of multiple different colors. As a result, toner images of multiple different colors are formed on each of the multiple photoconductor drums 101.

[0024] The transfer unit 12 includes an intermediate transfer belt 12a, a driving roller 12b, and a driven roller 12c. The intermediate transfer belt 12a is stretched around the driving roller 12b and the driven roller 12c. The intermediate transfer belt 12a is driven to rotate in a rotation direction RA by the driving roller 12b. A plurality of image forming units 11 transfer toner images of different colors onto the intermediate transfer belt 12a. The toner images of the different colors are superimposed on the intermediate transfer belt 12a, forming a toner image (specifically, a color image) on the intermediate transfer belt 12a. The transfer unit 12 transfers the toner image formed on the intermediate transfer belt 12a onto the sheet P.

[0025] Next, the configuration of the image forming unit 11 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing an example of the configuration of the image forming unit 11.

[0026] 2, the image forming unit 11 further includes a developing unit 110, a charging unit 102, a cleaning unit 103, and a supply path 210 in addition to the photoconductor drum 101. The photoconductor drum 101 has a substantially cylindrical or cylindrical shape. The photoconductor drum 101 rotates in a rotation direction RB around a rotation axis AX of the photoconductor drum 101. The photoconductor drum 101 is, for example, an amorphous silicon (α-Si) photoconductor drum or an organic photoconductor (OPC: Organic PhotoConductor) drum.

[0027] The charging unit 102 charges the entire surface of the photoconductor drum 101 to a predetermined potential. The charging unit 102 includes, for example, a charging roller. As shown in FIG. 1, the exposure unit 13 exposes a predetermined area of ​​the surface of the photoconductor drum 101 to light. As a result, an electrostatic latent image is formed in the predetermined area of ​​the surface of the photoconductor drum 101.

[0028] Furthermore, the developing unit 110 develops the electrostatic latent image formed in a predetermined area on the surface of the photoconductor drum 101 by the plurality of toner particles to form a toner image in the predetermined area on the surface of the photoconductor drum 101. The plurality of toner particles are contained in a two-component developer.

[0029] Specifically, the two-component developer includes a plurality of carrier particles (specifically, a large number of carrier particles) in addition to a plurality of toner particles (specifically, a large number of toner particles). The plurality of toner particles are powder, and the plurality of carrier particles are powder. The toner particles are, for example, positively charged toner particles. The positively charged toner particles are positively charged due to friction with the carrier particles. Positive is an example of a "set polarity."

[0030] The carrier particles are magnetic. The carrier particles are, for example, resin-coated carrier particles. The core particles of the resin-coated carrier particles are, for example, ferrite or magnetite. The particle size of the carrier particles is, for example, 20 μm or more and 100 μm or less, preferably 25 μm or more and 80 μm or less, in terms of volume average particle size.

[0031] Here, a development nip is formed between the development roller 112 and the photoconductor drum 101. When a development bias is applied to the development roller 112, an electric field is formed in the development nip. Therefore, the toner particles move from the development unit 110 to the photoconductor drum 101 due to the action of the electric field. As a result, the electrostatic latent image is visualized by the toner particles to form a toner image. The toner image is transferred to the intermediate transfer belt 12a shown in FIG. 1.

[0032] The developing unit 110 includes a developing housing 111 , a developing roller 112 , a first screw feeder 113 , a second screw feeder 114 , and a regulating blade 115 .

[0033] The developing roller 112 has a substantially columnar or cylindrical shape. The developing roller 112 is disposed facing the photosensitive drum 101. The developing roller 112 includes a sleeve 112S and a magnet 112M. The magnet 112M is disposed inside the sleeve 112S. The magnet 112M includes an S1 pole, an N1 pole, an S2 pole, an N2 pole, and an S3 pole. The N1 pole functions as a main pole, the S1 pole and the N2 pole function as transport poles, and the S2 pole functions as a peeling pole. The S3 pole functions as a pumping pole and a regulating pole.

[0034] The sleeve 112S is a non-magnetic cylinder (for example, an aluminum pipe). The sleeve 112S is driven by, for example, a motor to rotate around the magnet 112M in a rotation direction RC.

[0035] Therefore, while the sleeve 112S rotates in the rotation direction RC, the carrier particles are attracted by the magnetic force of the magnet 112M. As a result, a magnetic brush of carrier particles is formed on the surface of the developing roller 112. Specifically, a plurality of magnetic brushes are formed on the surface of the developing roller 112. Each of the plurality of magnetic brushes is made of a plurality of carrier particles. That is, each of the plurality of magnetic brushes is a carrier particle cluster standing on the surface of the developing roller 112. The toner particles are carried on the surface of the carrier particles. That is, the toner particles are carried on the surface of the developing roller 112 while being carried on the magnetic brush.

[0036] The regulating blade 115 is disposed at a predetermined interval from the developing roller 112. The regulating blade 115 regulates the length of the magnetic brush formed on the surface of the developing roller 112.

[0037] The developing housing 111 includes a transport section that accommodates the two-component developer. For example, the transport section has a first transport section 131 and a second transport section 132. In the first transport section 131, the two-component developer is transported in a first transport direction from one end side to the other end side in the axial direction of the developing roller 112. The second transport section 132 communicates with the first transport section 131 at both ends in the axial direction of the developing roller 112. In the second transport section 132, the two-component developer is transported in a second transport direction that is opposite to the first transport direction.

[0038] Specifically, the second transport section 132 includes a second screw feeder 114. The second screw feeder 114 is rotated in a rotation direction RE and transports the two-component developer in a second transport direction. The first transport section 131 includes a first screw feeder 113. The first screw feeder 113 is rotated in a rotation direction RD and transports the two-component developer in a first transport direction. The first screw feeder 113 supplies the two-component developer to the developing roller 112 while transporting the two-component developer in the first transport direction.

[0039] The toner particles contained in the two-component developer are triboelectrically charged between themselves and the carrier particles contained in the two-component developer, for example, while being circulated and transported in the first transport direction and the second transport direction.

[0040] The toner container 116 has a storage section R1 that stores toner particles for replenishing. The supply path 210 supplies toner from the toner container 116 to the image forming unit 11. The toner particles for replenishing are supplied from the storage section R1 of the toner container 116 to the second conveying unit 132 of the developing unit 110 through the supply path 210. The toner container 116 includes a supply amount adjustment member 116a. The supply amount adjustment member 116a adjusts the amount of toner supplied. The amount of toner supplied is the amount of toner supplied from the toner container 116 to the second conveying unit 132 through the supply path 210. The supply amount adjustment member 116a is composed of, for example, a screw shaft whose rotation operation is controlled by the control unit 20.

[0041] The image forming unit 11 further includes a toner charging unit 200. The toner charging unit 200 charges the toner passing through the supply path 210. Specifically, the toner charging unit 200 is a corona charging device. In more detail, the toner charging unit 200 charges the toner positively (a set polarity) or negatively (a polarity opposite to the set polarity).

[0042] The image forming unit 11 further includes a voltage application unit 21. The voltage application unit 21 applies a development bias to the development roller 112. The development bias is a voltage in which an AC voltage is superimposed on a DC voltage. The AC voltage is, for example, a square wave with a duty ratio of 50%. Specifically, the voltage application unit 21 has a DC power source and an AC power source. As a result, the development bias potential on the surface of the development roller 112 is a potential Vdc.

[0043] The charging unit 102 charges the surface of the photoconductor drum 101 to a predetermined potential V0 (V). The potential difference between the potential VL and the potential Vdc is the potential difference that moves the charged toner particles from the developing roller 112 to the electrostatic latent image. Specifically, the toner particles carried by the developing roller 112 are electrically attracted and fly toward the electrostatic latent image on the photoconductor drum 101. As a result, a toner image is formed on the electrostatic latent image on the photoconductor drum 101.

[0044] Next, the configuration of the image forming apparatus 100 according to the present embodiment will be described with reference to Fig. 3. Fig. 3 is a block diagram showing the configuration of the image forming apparatus 100. As shown in Fig. 3, the control unit 20 includes an acquisition unit 20a, a toner control unit 20c, and a charging control unit 20e. The processor of the control unit 20 executes a computer program stored in the storage device of the storage unit 80, thereby functioning as the acquisition unit 20a, the toner control unit 20c, and the charging control unit 20e.

[0045] The acquiring unit 20a acquires environmental information. For example, the acquiring unit 20a receives the environmental information from the detection unit 104 when an image is formed on the sheet P.

[0046] The toner control unit 20c controls the image forming unit 11 so as to supply toner from the developing unit 110 to the photoconductor drum 101 when forming an image on the sheet P. In addition, the toner control unit 20c supplies toner from a toner container 116 to the developing unit 110.

[0047] The charging control unit 20e controls the toner charging unit 200 based on the environmental information. Specifically, when the environmental information indicates high temperature and high humidity, the charging control unit 20e causes the toner to be positively charged (set polarity) by the toner charging unit 200. In other words, the toner is frictionally charged between the carrier particles while being circulated in the first transport direction and the second transport direction. However, when the environmental information indicates high temperature and high humidity, the charge amount of the toner is small, so the toner is positively charged (set polarity) before being circulated in the first transport direction and the second transport direction. As a result, the toner can be charged to an appropriate charge amount. Therefore, scattering of the toner can be suppressed when the electrostatic latent image is developed with the toner.

[0048] On the other hand, when the environmental information indicates low temperature and low humidity, the charging control unit 20e causes the toner to be negatively charged (opposite polarity of the set polarity) by the toner charging unit 200. In other words, while the toner is circulated in the first transport direction and the second transport direction, it is frictionally charged between the toner and the carrier particles. However, when the environmental information indicates low temperature and low humidity, the charge amount of the toner increases, so the toner is negatively charged (opposite polarity of the set polarity) before being circulated in the first transport direction and the second transport direction. As a result, the toner can be charged to an appropriate charge amount. Therefore, scattering of the toner can be suppressed when the electrostatic latent image is developed with the toner.

[0049] The charging control unit 20e does not charge the toner by the toner charging unit 200 when the environmental information does not indicate high temperature and high humidity or low temperature and low humidity.

[0050] Next, an example of the process of the control unit 20 according to the present embodiment will be described with reference to Fig. 4. Fig. 4 is a flowchart showing an example of the process of the control unit 20. The process of the control unit 20 according to the present embodiment includes steps S101 to S104.

[0051] First, in step S101, the acquisition unit 20a acquires environmental information, and the process proceeds to step S102.

[0052] Next, in step S102, the charging control unit 20e determines what the environmental information indicates. If the charging control unit 20e determines that the environmental information indicates low temperature and low humidity, the process proceeds to step S103. In step S103, the charging control unit 20e causes the toner charging unit 200 to charge the toner positively (set polarity), and the process ends.

[0053] If the charging control unit 20e determines that the environmental information indicates high temperature and high humidity, the process proceeds to step S104. In step S104, the charging control unit 20e causes the toner charging unit 200 to charge the toner negatively (opposite polarity to the set polarity), and the process ends.

[0054] Furthermore, if the charging control section 20e determines that the environmental information does not indicate either low temperature and low humidity or high temperature and high humidity, the process ends.

[0055] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments, and can be implemented in various aspects without departing from the gist of the present invention. In addition, various inventions can be formed by appropriately combining multiple components disclosed in the above embodiments. For example, some components may be deleted from all components shown in the embodiments. Furthermore, components across different embodiments may be appropriately combined. The drawings are mainly shown schematically for ease of understanding, and the thickness, length, number, spacing, etc. of each component shown in the drawings may differ from the actual ones due to the convenience of drawing. In addition, the material, shape, dimensions, etc. of each component shown in the above embodiments are only examples and are not particularly limited, and various changes are possible within a range that does not substantially deviate from the effects of the present invention.

[0056] As described with reference to FIGS. 1 to 4, in this embodiment, the image forming apparatus 100 is a color multifunction device, but the present invention is not limited to this. The image forming apparatus may form a toner image on a sheet P. The image forming apparatus may be, for example, a color printer. The image forming apparatus may also be, for example, a monochrome copier. [Industrial Applicability]

[0057] The present invention relates to an image forming apparatus and has industrial applicability. [Explanation of symbols]

[0058] 11 Image forming section 20 Control section 104 Detection unit 116 Toner Container 200 Toner charging unit 210 Supply route

Claims

1. a mounting portion to which a toner container containing toner can be detachably attached; an image forming section for forming an image on a sheet using the toner; a supply path for supplying the toner from the toner container to the image forming unit; a toner charging section that charges the toner passing through the supply path; A detection unit that detects environmental information; a control unit that controls the toner charging unit based on the environmental information; An image forming apparatus comprising:

2. The image forming unit includes: a photoconductor drum on which an electrostatic latent image is formed; a developing section for developing the electrostatic latent image with the toner; Equipped with the developing unit includes a transport unit that contains the toner and the carrier; The image forming apparatus according to claim 1 , wherein the toner is triboelectrically charged between the toner and the carrier while moving within the transport section.

3. The developing unit charges the toner to a set polarity, The image forming apparatus according to claim 2 , wherein the control unit causes the toner charging unit to charge the toner to the set polarity when the environmental information indicates high temperature and high humidity.

4. The image forming apparatus according to claim 3 , wherein the control unit causes the toner charging unit to charge the toner to a polarity opposite to the set polarity when the environmental information indicates low temperature and low humidity.

Images