JP2020144334A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can form an image on a sheet with a highly accurate image density.SOLUTION: An image forming apparatus 100 comprises: an image forming unit; and a control unit 20. The image forming unit forms an image on a sheet. The control unit 20 controls the image forming unit. The image forming unit includes a photoreceptor drum and a developing unit. The photoreceptor drum has an electrostatic latent image corresponding to the image formed thereon. The developing unit develops the electrostatic latent image with toner. The control unit 20 includes a first calculation unit 20b and a toner control unit 20c. The first calculation unit 20b calculates the amount of toner supplied from the developing unit to the photoreceptor drum based on the printing rate of the image. The toner control unit 20c controls the image forming unit to supply the toner in the amount calculated by the first calculation unit 20b from the developing unit to the photoreceptor drum as a running-in operation before forming the image on the sheet.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus.

The image forming apparatus described in Patent Document 1 includes a developing unit, a control unit, and a charge amount detecting means. The developing unit develops an electrostatic latent image on the photoconductor drum to form a toner image. The charge amount detecting means detects the charge amount of the toner. The control unit forcibly discharges the deteriorated toner from the developing unit based on the detection result of the charge amount detecting means.

Japanese Unexamined Patent Publication No. 2006-243114

Generally, the amount of charge of the toner is affected by the state in which the toner passes through the developing unit. When a small amount of toner passes through the developing unit, the amount of charge in the toner is high. On the other hand, when a large amount of toner passes through the developing unit, the amount of charge of the toner is low.

However, in the image forming apparatus described in Patent Document 1, deteriorated toner that does not increase the charge amount of the toner is forcibly discharged from the developing unit, but the charge amount of the toner when forming an image on the sheet and the charge amount detection. The amount of charge of the toner detected immediately before by the means may be different. Therefore, the image forming apparatus described in Patent Document 1 could not form an image on a sheet with a high-precision image density.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an image forming apparatus capable of forming an image on a sheet with a high-precision image density.

According to one aspect of the present invention, the image forming apparatus includes an image forming unit and a control unit. The image forming unit forms an image on the sheet. The control unit controls the image forming unit. The image forming unit includes a photoconductor drum and a developing unit. An electrostatic latent image corresponding to the image is formed on the photoconductor drum. The developing unit develops the electrostatic latent image with toner. The control unit includes a first calculation unit and a toner control unit. The first calculation unit calculates the amount of the toner supplied from the developing unit to the photoconductor drum based on the printing rate of the image. The toner control unit performs the image as a break-in operation before forming the image on the sheet so as to supply the toner in the amount calculated by the first calculation unit from the developing unit to the photoconductor drum. Control the forming part.

According to the image forming apparatus of the present invention, an image can be formed on a sheet with a high-precision image density.

It is a figure which shows the structure of the image forming apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows an example of the structure of the image forming part which concerns on Embodiment 1. FIG. It is a top view which shows an example of the structure of the photoconductor drum which formed the electrostatic latent image which concerns on Embodiment 1. FIG. It is a block diagram which shows the structure of the image forming apparatus which concerns on Embodiment 1. FIG. It is a flowchart which shows an example of the processing of the control part which concerns on Embodiment 1.

[Embodiment 1]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description is not repeated. In the embodiment, the X-axis and the Y-axis are along the horizontal direction, the Z-axis is along the vertical direction, and the X-axis, the Y-axis, and the Z-axis are orthogonal to each other.

First, the configuration of the image forming apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 1 is a diagram showing a configuration of an image forming apparatus 100. The image forming apparatus 100 is, for example, a color multifunction device.

As shown in FIG. 1, the image forming apparatus 100 includes an image forming unit 10, a feeding unit 30, a conveying unit 40, a fixing unit 50, a discharging unit 60, a control unit 20, a storage unit 80, an operation unit 120, and a document feeding unit. A unit 90, a scanner unit 91, and a density sensor 104 are provided.

The document feeding section 90 includes a document placing section 90a. The document feeding unit 90 conveys the document G set in the document placing unit 90a to the reading position of the scanner unit 91.

The scanner unit 91 irradiates the document G with an exposure lamp and receives the reflected light with a CCD (Charge Coupled Device) to read an image from the document G and generate image data indicating the image. The image data includes, for example, a plurality of pixel data indicating a plurality of gradation values. Then, the scanner unit 91 outputs the image data to the control unit 20.

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

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

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

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.

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.

Next, the configuration of the image forming unit 10 will be described. The image forming unit 10 includes a plurality of image forming units 11, an exposure unit 13, and a transfer unit 12. That is, there are a plurality of image forming units 11.

Toners of a plurality of colors different from each other are supplied to the plurality of image forming units 11. Toner contains a large number of toner particles. Each of the plurality of image forming units 11 includes a photoconductor drum 101. For example, the plurality of image forming units 11 include an image forming unit 11c to which cyan toner is supplied, an image forming unit 11m to which magenta toner is supplied, an image forming unit 11y to which yellow toner is supplied, and , Includes an image forming unit 11k to which black toner is supplied. The configurations of the image forming unit 11c, the image forming unit 11m, the image forming unit 11y, and the image forming unit 11k are substantially the same as each other.

The exposure unit 13 irradiates each of the plurality of photoconductor drums 101 with laser light. As a result, an electrostatic latent image is formed on each of the plurality of photoconductor drums 101. Then, each of the plurality of image forming units 11 develops a plurality of electrostatic latent images. The plurality of electrostatic latent images are developed by toners of a plurality of colors different from each other. As a result, toner images of a plurality of colors different from each other are formed on the plurality of photoconductor drums 101.

The transfer unit 12 includes an intermediate transfer belt 12a, a drive roller 12b, and a driven roller 12c. The intermediate transfer belt 12a is stretched on the driving roller 12b and the driven roller 12c. The intermediate transfer belt 12a is rotationally driven in the rotational direction RA by the drive roller 12b. The plurality of image forming units 11 transfer toner images of a plurality of colors different from each other onto the intermediate transfer belt 12a. By superimposing the toner images of a plurality of colors on the intermediate transfer belt 12a, a toner image (specifically, a color image) is formed 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.

The density sensor 104 is arranged on the downstream side of the plurality of photoconductor drums 101. The density sensor 104 detects the density of the toner image formed on the intermediate transfer belt 12a. The toner image is, for example, a patch image for calculating the charge amount of the toner at the time of calibrating the charge amount of the toner. The density of the toner image indicates the mass of the toner forming the toner image per unit area. Therefore, the density of the toner image is calculated based on the thickness of the toner image. In the first embodiment, the density sensor 104 detects the thickness HT of the toner image. Specifically, the density sensor 104 measures the distance LT from the toner image to detect the thickness HT of the toner image. More specifically, the density sensor 104 detects the thickness HT of the toner image using the following formula (1).
(Thickness HT) = (Reference distance LTA)-(Distance LT) (1)
The reference distance LTA indicates the distance between the density sensor 104 and the surface of the intermediate transfer belt 12a.

The density sensor 104 is, for example, a laser displacement sensor. The laser displacement sensor includes a semiconductor laser and a linear image sensor (Linear Image Sensor), and measures the distance LT using triangular ranging. Then, the density sensor 104 outputs a detection signal SG1 indicating the density of the toner image to the control unit 20.

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

As shown in FIG. 2, the image forming unit 11 further includes a developing unit 110, a charging unit 102, a cleaning unit 103, and a toner container 116 in addition to the photoconductor drum 101. The photoconductor drum 101 has a substantially cylindrical shape or a substantially cylindrical shape. The photoconductor drum 101 rotates in the rotation direction RB about the 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) drum.

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. Then, as shown in FIG. 1, the exposure unit 13 exposes a predetermined region on the surface of the photoconductor drum 101. As a result, an electrostatic latent image is formed in a predetermined region on the surface of the photoconductor drum 101.

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

Specifically, the two-component developer contains a plurality of carrier particles (specifically, a large number of carrier particles) in addition to the plurality of toner particles (specifically, a large number of toner particles). The plurality of toner particles are powders, and the plurality of carrier particles are powders. The toner particles are, for example, positively charged toner particles. The positively charged toner particles are positively charged by friction with the carrier particles.

The particle size of the toner particles is, for example, 5.0 μm or more and 8.0 μm or less, preferably 5.2 μm or more and 6.7 μm or less in terms of volume-based median diameter (D50).

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.

Here, a developing nip portion is formed between the developing roller 112 and the photoconductor drum 101. Then, when a development bias is applied to the developing roller 112, an electric field is formed in the developing nip portion. Therefore, the toner particles move from the developing unit 110 to the photoconductor drum 101 by 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.

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 regulation blade 115.

The developing roller 112 has a substantially cylindrical shape or a substantially cylindrical shape. The developing roller 112 is arranged so as to face the photoconductor drum 101. The developing roller 112 includes a sleeve 112S and a magnet 112M. The magnet 112M is arranged inside the sleeve 112S. The magnet 112M includes S1 pole, N1 pole, S2 pole, N2 pole and S3 pole. The N1 pole functions as a main pole, the S1 pole and the N2 pole function as a transport pole, and the S2 pole functions as a peeling pole. Further, the S3 pole functions as a pumping pole and a regulating pole.

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

Therefore, the sleeve 112S attracts the carrier particles by the magnetic force of the magnet 112M while rotating in the rotation direction RC. As a result, a magnetic brush made 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 consists of a plurality of carrier particles. That is, each of the plurality of magnetic brushes is a carrier particle cluster that has spiked on the surface of the developing roller 112. The toner particles are supported on the surface of the carrier particles. That is, the toner particles are supported on the surface of the developing roller 112 in a state of being supported on the magnetic brush.

The regulation blades 115 are arranged at predetermined intervals with respect to the developing roller 112. The regulating blade 115 regulates the length of the magnetic brush formed on the surface of the developing roller 112.

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

Specifically, the second transport unit 132 includes a second screw feeder 114. The second screw feeder 114 is rotated in the rotation direction RE to convey the two-component developer in the second transfer direction. The first transport unit 131 includes a first screw feeder 113. The first screw feeder 113 is rotated in the rotation direction RD to convey the two-component developer in the first transfer direction. The first screw feeder 113 supplies the two-component developer to the developing roller 112 while conveying the two-component developer in the first transfer direction.

The toner particles contained in the two-component developer are triboelectrically charged with 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.

The toner container 116 has an accommodating portion R1 accommodating the toner particles for replenishment. The replenishment toner particles are replenished from the accommodating portion R1 of the toner container 116 to the second transport portion 132 of the developing unit 110. The toner container 116 includes a replenishment amount adjusting member 116a. The replenishment amount adjusting member 116a adjusts the replenishment amount of toner. The amount of toner replenished is the amount of toner replenished from the toner container 116 to the second transport unit 132. The replenishment amount adjusting member 116a is composed of, for example, a screw shaft whose rotational operation is controlled by the control unit 20.

The image forming unit 11 further includes a driving unit 23, a voltage applying unit 21, and a current detecting unit 22.

The drive unit 23 rotationally drives the photoconductor drum 101, the developing roller 112, the first screw feeder 113, the second screw feeder 114, and the replenishment amount adjusting member 116a. The drive unit 23 has, for example, a motor and a gear mechanism.

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 having a duty ratio of 50%. Specifically, the voltage application unit 21 has a DC power supply and an AC power supply. As a result, the development bias potential on the surface of the development roller 112 is the potential Vdc.

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 supported on the developing roller 112 are electrically attracted and fly toward the electrostatic latent image of the photoconductor drum 101. As a result, a toner image is formed on the electrostatic latent image of the photoconductor drum 101.

The current detection unit 22 detects the current value of the current flowing between the photoconductor drum 101 and the developing roller 112. Then, the current detection unit 22 outputs a detection signal SG2 indicating the current value of the current flowing between the photoconductor drum 101 and the developing roller 112 to the control unit 20.

Next, the configuration of the photoconductor drum 101 on which the electrostatic latent image GA is formed will be described with reference to FIG. FIG. 3 is a plan view showing an example of the configuration of the photoconductor drum 101 on which the electrostatic latent image GA is formed. In FIG. 3, the photoconductor drum 101 is viewed from a direction orthogonal to the rotation axis AX of the photoconductor drum 101. Hereinafter, viewing the photoconductor drum 101 from a direction orthogonal to the rotation axis AX may be referred to as "planar view".

As shown in FIG. 3, the axial length of the surface of the photoconductor drum 101 is the first length LA.

The surface of the photoconductor drum 101 has a first region EA and a plurality of second region EBs. The plurality of second region EBs have a second region EBA and a second region EBB.

The second region EBA is located upstream of the first region EA in the rotational direction RB of the photoconductor drum 101 in the circumferential direction of the photoconductor drum 101. Further, the second region EBB is located downstream of the first region EA in the circumferential direction of the photoconductor drum 101 in the rotation direction RB of the photoconductor drum 101.

The first region EA has an electrostatic latent image GA, a partially blank paper portion EAA, and a partially blank paper portion EAB. The electrostatic latent image GA has a second length LB in the axial direction of the photoconductor drum 101. The electrostatic latent image GA has a third length LC in the circumferential direction of the photoconductor drum 101.

The electrostatic latent image GA is formed in a predetermined region in the first region EA. The exposure unit 13 shown in FIG. 1 includes, for example, a light source, a polygon mirror, a reflection mirror, and a deflection mirror. Specifically, after being charged to a predetermined potential V0 (V) by the charging unit 102, when a predetermined region is irradiated with laser light having a predetermined intensity or a predetermined amount of light by the exposure unit 13, the surface of the photoconductor drum 101 is static. The electric latent image GA is formed, and the potential of the electrostatic latent image GA changes from the potential V0 to the potential VL (V).

The configuration of the image forming apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 4 is a block diagram showing the configuration of the image forming apparatus 100. As shown in FIG. 4, the control unit 20 includes an acquisition unit 20a, a first calculation unit 20b, a toner control unit 20c, and a drive control unit 20d. Then, the processor of the control unit 20 functions as the acquisition unit 20a, the first calculation unit 20b, the toner control unit 20c, and the drive control unit 20d by executing the computer program stored in the storage device of the storage unit 80.

The acquisition unit 20a acquires image data. For example, when the acquisition unit 20a receives the print job from the operation unit 120, the acquisition unit 20a receives the image data from the scanner unit 91. The print job indicates an instruction to form an image on the sheet P. The acquisition unit 20a may receive image data from an external device.

The first calculation unit 20b calculates the amount of toner supplied from the developing unit 110 to the photoconductor drum 101 based on the printing rate of the image. Specifically, the first calculation unit 20b calculates the print rate of the image based on the image data, and calculates the amount of toner. Therefore, the print rate of the image can be calculated accurately. As a result, the amount of toner can be calculated accurately.

Further, when the image data includes information indicating a color image in which images of a plurality of colors are superimposed, the first calculation unit 20b determines the amount of cyan toner CSc, the amount of magenta toner CSm, and the yellow color. The amount of toner CSy and the amount of black-colored toner CSk are calculated.

Specifically, the first calculation unit 20b calculates the CMYK value for each of the plurality of pixel data included in the image data. The first calculation unit 20b calculates the total gradation value for each of a plurality of colors in all pixel data. Specifically, the total value SMc of the cyan gradation values in all the pixel data is calculated. The total value SMm of the gradation values of magenta colors in all pixels is calculated. The total value SMy of the yellow gradation values in all the pixels is calculated. The total value SMk of the gradation value of the black color in all the pixels is calculated.

Then, the first calculation unit 20b calculates the amount CSc of the cyan color toner from the total value SMc based on the table or formula showing the relationship between the total value SMc and the amount CSc of the cyan color toner. Similarly, the first calculation unit 20b calculates the amount of magenta toner CSm from the total value SMm, calculates the amount of yellow toner CSy from the total value SMy, and calculates the amount of yellow toner CSy from the total value SMk, and the amount of black toner from the total value SMk. Calculate CSk.

When the print job is received, the toner control unit 20c controls the image forming unit 11 so that the amount of toner calculated by the first calculation unit 20b is supplied from the developing unit 110 to the photoconductor drum 101. Specifically, when the toner control unit 20c forms an image on the sheet P, the toner control unit 20c forms an electrostatic latent image corresponding to the image on the photoconductor drum 101 while carrying the sheet P.

Specifically, the toner control unit 20c forms an electrostatic latent image corresponding to the cyan image on the photoconductor drum 101 of the image forming unit 11c. As a result, the cyan-colored toner of the amount CSc passes through the developing unit 110 while being triboelectrically charged, and then is supplied from the developing unit 110 to the photoconductor drum 101. The toner control unit 20c forms an electrostatic latent image corresponding to a magenta color image on the photoconductor drum 101 of the image forming unit 11m. As a result, a magenta-colored toner having an amount of CSm passes through the developing unit 110 while being triboelectrically charged, and then is supplied from the developing unit 110 to the photoconductor drum 101. The toner control unit 20c forms an electrostatic latent image corresponding to the yellow image on the photoconductor drum 101 of the image forming unit 11y. As a result, a yellow toner in an amount of CSy passes through the developing unit 110 while being triboelectrically charged, and then is supplied from the developing unit 110 to the photoconductor drum 101. The toner control unit 20c forms an electrostatic latent image corresponding to the black image on the photoconductor drum 101 of the image forming unit 11k. As a result, a black toner in an amount of CSk passes through the developing unit 110 while being triboelectrically charged, and then is supplied from the developing unit 110 to the photoconductor drum 101.

Further, the toner control unit 20c is an image forming unit so as to supply the amount of toner calculated by the first calculation unit 20b from the developing unit 110 to the photoconductor drum 101 as a break-in operation before forming an image on the sheet P. 11 is controlled. That is, after accepting the print job, the sheet P is not first conveyed, but the break-in operation is executed. The break-in operation is a break-in operation (aging) in which the state of the toner when an image is formed on the sheet P is equal to the state of the toner before the image is formed on the sheet P.

Therefore, according to the first embodiment, as a break-in operation, the amount of toner calculated by the first calculation unit 20b is supplied from the developing unit 110 to the photoconductor drum 101. As a result, the state in which the toner when forming an image on the sheet P passes through the developing unit 110 and the state in which the nearest toner forming an image on the sheet P passes through the developing unit 110 become equal. In particular, the charge amount of the toner when forming an image on the sheet P and the charge amount of the nearest toner forming an image on the sheet P are equal. Therefore, an image can be formed on the sheet P with a high-precision image density.

Specifically, the toner control unit 20c forms an electrostatic latent image having a size corresponding to the amount of toner calculated by the first calculation unit 20b on the photoconductor drum 101, and the first calculation unit 20b The calculated amount of toner is supplied from the developing unit 110 to the photoconductor drum 101. Therefore, according to the first embodiment, the size of the electrostatic latent image can be adjusted to easily supply the amount of toner calculated by the first calculation unit 20b.

Specifically, the toner control unit 20c forms an electrostatic latent image having a second length LB in the axial direction of the photoconductor drum 101 on the photoconductor drum 101, and the amount calculated by the first calculation unit 20b. Toner is supplied from the developing unit 110 to the photoconductor drum 101. The second length LB corresponds to the amount of toner calculated by the first calculation unit 20b.

Further, the toner control unit 20c forms an electrostatic latent image having a third length LC in the circumferential direction of the photoconductor drum 101 on the photoconductor drum 101, and produces an amount of toner calculated by the first calculation unit 20b. Supplying the photoconductor drum 101 from the developing unit 110 is executed for a predetermined time. The third length LC corresponds to a predetermined time for supplying the amount of toner calculated by the first calculation unit 20b. The predetermined time is preferably 30 seconds or more and 3 minutes or less.

Specifically, the toner control unit 20c transmits an electrostatic latent image having a size corresponding to the amount CSc of the cyan-colored toner calculated by the first calculation unit 20b to the photoconductor drum 101 of the image forming unit 11c. Form. As a result, after the cyan-colored toner of the amount CSc passes through the developing unit 110 while being triboelectrically charged, it is supplied from the developing unit 110 to the photoconductor drum 101 for a predetermined time. The toner control unit 20c forms an electrostatic latent image having a size corresponding to the amount CSm of magenta-colored toner calculated by the first calculation unit 20b on the photoconductor drum 101 of the image forming unit 11m. As a result, after a magenta-colored toner having an amount of CSm passes through the developing unit 110 while being triboelectrically charged, it is supplied from the developing unit 110 to the photoconductor drum 101 for a predetermined time. The toner control unit 20c forms an electrostatic latent image having a size corresponding to the amount CSm of magenta-colored toner calculated by the first calculation unit 20b on the photoconductor drum 101 of the image forming unit 11y. As a result, after the yellow toner of the amount CSy passes through the developing unit 110 while being triboelectrically charged, it is supplied from the developing unit 110 to the photoconductor drum 101 for a predetermined time. The toner control unit 20c forms an electrostatic latent image having a size corresponding to the amount CSm of magenta-colored toner calculated by the first calculation unit 20b on the photoconductor drum 101 of the image forming unit 11k. As a result, after the black toner of the amount CSk passes through the developing unit 110 while being triboelectrically charged, it is supplied from the developing unit 110 to the photoconductor drum 101 for a predetermined time.

Therefore, according to the first embodiment, since the amounts of toners of a plurality of colors CSc, CSm, CSy, and CSk are calculated, a color image can be formed on the sheet P with a high-precision image density.

The drive control unit 20d controls the drive unit 23 to rotationally drive the photoconductor drum 101, the developing roller 112, the first screw feeder 113, the second screw feeder 114, and the replenishment amount adjusting member 115a. For example, when the drive control unit 20d supplies the amount of toner calculated by the first calculation unit 20b to the photoconductor drum 101 from the developing unit 110, the drive control unit 20d supplies the amount of toner calculated by the first calculation unit 20b to the toner container. The developing unit 110 is replenished from 116.

Next, an example of the processing of the control unit 20 according to the first embodiment will be described with reference to FIG. FIG. 5 is a flowchart showing an example of processing by the control unit 20. The process of the control unit 20 according to the first embodiment includes steps S101 to S108.

First, in step S101, the acquisition unit 20a acquires image data when it receives a print job. Then, the process proceeds to step S102.

Next, in step S102, the first calculation unit 20b calculates the amount of toner supplied from the developing unit 110 to the photoconductor drum 101 based on the print rate of the image. Then, the process proceeds to step S103.

Next, in step S103, the toner control unit 20c controls the exposure unit 13 so as to form an electrostatic latent image GA having a size corresponding to the amount of toner calculated by the first calculation unit 20b. Then, the process proceeds to step S104.

Next, in step S104, the toner control unit 20c controls the image forming unit 11 so that the amount of toner calculated by the first calculation unit 20b is supplied from the developing unit 110 to the photoconductor drum 101, and the toner is supplied. Form an image. Then, the process proceeds to step S105.

Next, in step S105, the toner control unit 20c determines whether or not a predetermined time has elapsed. When the toner control unit 20c determines that the predetermined time has not elapsed (NO in step S105), the process returns to step S103. On the other hand, when the toner control unit 20c determines that the predetermined time has elapsed (YES in step S105), the process proceeds to step S106.

If YES in step S105, in step S106, the toner control unit 20c controls the exposure unit 13 so as to form the electrostatic latent image GA corresponding to the image. Then, the process proceeds to step S107.

Next, in step S107, the toner control unit 20c controls the image forming unit 11 so that the amount of toner calculated by the first calculation unit 20b is supplied from the developing unit 110 to the photoconductor drum 101, and the toner is supplied. Form an image. Then, the process proceeds to step S108.

Next, in step S108, the control unit 20 controls the image forming unit 10 to form an image on the sheet P, and the process ends.

[Embodiment 2]
Next, the image forming apparatus 100 according to the second embodiment will be described with reference to FIG. The second embodiment is different from the first embodiment in that it determines whether or not the number of sheets is a predetermined number or more.

As shown in FIG. 4, the control unit 20 further includes a determination unit 20e.

The acquisition unit 20a acquires a plurality of image data indicating an image formed for each of the plurality of sheets. For example, the acquisition unit 20a receives a plurality of image data from the scanner unit 91.

The determination unit 20e determines whether or not the plurality of images is a predetermined number or more based on the plurality of image data. The predetermined number of sheets is preferably 30.

The first calculation unit 20b calculates the average value of the print rate of the image based on the plurality of image data, and calculates the amount of toner based on the average value of the print rate of the image.

Based on the determination result of the determination unit 20e, the toner control unit 20c supplies the amount of toner calculated by the first calculation unit 20b from the developing unit 110 to the photoconductor drum 101 as a break-in operation. To control. Specifically, when the number of sheets is a predetermined number or more, the amount of toner calculated by the first calculation unit 20b is supplied from the developing unit 110 to the photoconductor drum 101 before forming an image on the sheet P. On the other hand, when the number of sheets is less than the predetermined number, the amount of toner calculated by the first calculation unit 20b is not supplied from the developing unit 110 to the photoconductor drum 101 before the image is formed on the sheet P.

Therefore, according to the second embodiment, since it is determined whether or not the plurality of sheets is a predetermined number or more, it is possible to prevent the break-in operation from being executed in order to form an image on a small number of sheets P. Further, since the amount of toner is calculated based on the average value of the print rate of the image, it is possible to form an image in which the change in image density is suppressed on a predetermined number of sheets P.

[Embodiment 3]
Next, the image forming apparatus 100 according to the third embodiment will be described with reference to FIG. The third embodiment is different from the first embodiment in that the amount of charge of the toner is calculated.

As shown in FIG. 4, the control unit 20 further includes a second calculation unit 20f.

The second calculation unit 20f calculates the charge amount of the toner after the toner control unit 20c executes the break-in operation and before forming an image on the sheet P. Specifically, the second calculation unit 20f forms a patch image on the photoconductor drum 101 after the break-in operation is executed and before the image is formed on the sheet P. Then, the second calculation unit 20f receives the detection signal SG1 indicating the density of the patch image transferred from the photoconductor drum 101 to the intermediate transfer belt 12a, and the current value of the current flowing between the photoconductor drum 101 and the developing roller 112. The amount of charge of the toner is calculated based on the detection signal SG2 indicating.

Therefore, according to the third embodiment, the charge amount of the toner when forming an image on the sheet P can be equal to the charge amount of the nearest toner forming an image on the sheet P. As a result, an image can be formed on the sheet P with a higher precision image density by using the same amount of charge of the toner.

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-described embodiment, and can be implemented in various embodiments without departing from the gist thereof. In addition, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiments. For example, some components may be removed from all the components shown in the embodiments. Further, components over different embodiments may be combined as appropriate. In order to make the drawings easier to understand, each component is schematically shown, and the thickness, length, number, spacing, etc. of each component shown are actual for the convenience of drawing creation. May be different. Further, the material, shape, dimensions, etc. of each component shown in the above-described embodiment are merely examples, and are not particularly limited, and various changes can be made without substantially deviating from the effects of the present invention. is there.

(1) As described with reference to FIGS. 1 to 5, in the present embodiment, the image forming apparatus 100 is a color multifunction device, but the present invention is not limited thereto. The image forming apparatus may form a toner image on the sheet P. The image forming apparatus may be, for example, a color printer. Further, the image forming apparatus may be, for example, a monochrome copier.

(2) In the present embodiment, the toner control unit 20c forms an electrostatic latent image having a size corresponding to the amount of toner calculated by the first calculation unit 20b on the photoconductor drum 101, and performs the first calculation. The amount of toner calculated in unit 20b was supplied from the developing unit 110 to the photoconductor drum 101, but the present invention is not limited to this. The toner control unit 20c forms an electrostatic latent image having a potential VL corresponding to the amount of toner calculated by the first calculation unit 20b on the photoconductor drum 101, and the amount calculated by the first calculation unit 20b. Toner may be supplied from the developing unit 110 to the photoconductor drum 101. Specifically, the toner control unit 20c controls a predetermined intensity or a predetermined amount of light of the laser light emitted from the exposure unit 13.

The present invention relates to an image forming apparatus and has industrial applicability.

10 Image forming unit 20 Control unit 20b First calculation unit 20c Toner control unit 100 Image forming apparatus 101 Photoreceptor drum 110 Developing unit

Claims (8)

An image forming part that forms an image on the sheet,
A control unit that controls the image forming unit is provided.
The image forming part is
A photoconductor drum on which an electrostatic latent image corresponding to the image is formed, and
Includes a developing unit that develops the electrostatic latent image with toner.
The control unit
A first calculation unit that calculates the amount of the toner supplied from the development unit to the photoconductor drum based on the print rate of the image.
As a break-in operation before forming the image on the sheet, the toner that controls the image forming unit so that the amount of the toner calculated by the first calculation unit is supplied from the developing unit to the photoconductor drum. An image forming apparatus including a control unit. The control unit further includes an acquisition unit for acquiring image data.
The image forming apparatus according to claim 1, wherein the first calculation unit calculates a print rate of the image based on the image data. The acquisition unit acquires a plurality of the image data showing the images formed for each of the plurality of sheets, and obtains the plurality of image data.
The control unit further includes a determination unit for determining whether or not the plurality of sheets is a predetermined number or more.
The image forming unit controls the image forming unit so as to supply the amount of the toner from the developing unit to the photoconductor drum as the break-in operation based on the determination result of the determination unit. 2. The image forming apparatus according to 2. The first calculation unit
Based on the plurality of image data, the average value of the print rate of the image is calculated.
The image forming apparatus according to claim 3, wherein the amount of the toner is calculated based on the average value of the print rates of the images. There are a plurality of the image forming portions,
Each of the plurality of image forming units develops the plurality of the electrostatic latent images.
The plurality of electrostatic latent images are developed by toners of a plurality of colors different from each other.
The image data includes information indicating a color image on which the images of the plurality of colors are superimposed.
The first calculation unit calculates the amount of each of the plurality of color toners based on the printing rate of each of the plurality of color images.
The image forming apparatus according to any one of claims 2 to 4, wherein the toner control unit controls the plurality of image forming units. The developing unit includes a transport unit that houses the toner and the carrier.
The image forming apparatus according to any one of claims 1 to 5, wherein the toner is triboelectrically charged with the carrier while moving in the transport unit. 6. The control unit further includes a second calculation unit for calculating the charge amount of the toner after the toner control unit executes the break-in operation and before forming the image on the sheet. Image forming device. The toner control unit
The electrostatic latent image having a size corresponding to the amount of the toner calculated by the first calculation unit is formed on the photoconductor drum.
The image forming apparatus according to any one of claims 1 to 7, wherein the amount of the toner is supplied from the developing unit to the photoconductor drum.

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