JP6304097B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  In an image forming apparatus typified by a digital multifunction peripheral or the like, after an image of a document is read by an image reading unit, light is irradiated to the photoconductor provided in the image forming unit based on the read image, and the photoconductor An electrostatic latent image is formed thereon. Thereafter, a developer such as charged toner is supplied onto the formed electrostatic latent image to form a visible image, and then transferred to a sheet, fixed, and discharged outside the apparatus.

  Here, during image formation, toner that is a consumable item is consumed as needed. The amount of toner consumed may differ greatly when a character image is formed and when a non-character image, for example, a photographic image is formed. From the viewpoint of accurately predicting the remaining number of images that can be formed, in the image forming apparatus, it is desired to calculate the toner consumption with high accuracy for the image to be formed.

  Japanese Unexamined Patent Application Publication No. 2012-48055 (Patent Document 1) discloses a technique related to the calculation of toner consumption. According to Patent Document 1, based on attribute data of each pixel included in the target image, an image attribute identification unit for identifying whether each pixel is a character part or a gradation part, and a predetermined calculation corresponding to the character part or the gradation part An image forming apparatus including a toner consumption amount calculation unit that performs processing to calculate the consumption amount of toner used for forming a target image is disclosed.

JP 2012-48055 A

  According to the technique disclosed in Japanese Patent Laid-Open No. 2004-260, the character part or the gradation part is identified by using the information on the character part or the gradation part grasped at the time of image generation, that is, the rasterizing process, and individually. The toner consumption is calculated by counting dots.

  However, even within the same character part, the amount of toner consumption may differ, and simply calculating the toner consumption with high accuracy simply by identifying the character part and the gradation part and counting the dots individually. May not be possible. That is, when calculating the toner consumption amount, if the character portion is calculated as a uniform consumption amount, the toner consumption amount cannot be accurately calculated.

  An object of the present invention is to provide an image forming apparatus capable of accurately calculating a toner consumption amount.

In one aspect of the present invention, an image forming apparatus includes a photosensitive member, an input unit, an exposure unit, an image forming unit, a transfer member, an output unit, a character image determination unit, and a dot continuity determination unit. And a toner consumption amount calculation unit. The input unit inputs image data. The exposure unit irradiates the photosensitive member with light to form an electrostatic latent image on the photosensitive member based on the image data input by the input unit. The image forming unit supplies toner to the electrostatic latent image formed by the exposure unit to form a visible image using the toner on the photoreceptor. The transfer body transfers a visible image by toner formed by the image forming unit. The output unit transfers the visible image of the toner transferred to the transfer body to a recording medium, forms an image based on the image data on the recording medium, and outputs the image. The character image determining unit determines a character image and an image other than the character image from the image data input by the input unit. The dot continuity determination unit determines the continuity of the dots of the pixels constituting the edge of the character image determined by the image determination unit. The toner consumption calculation unit calculates the toner consumption when the visible image is formed by the image forming unit according to the dot continuity determined by the dot continuity determination unit. The toner consumption amount calculating unit consumes more toner than the dots having a dot continuity greater than a predetermined number if the dot continuity determined by the dot continuity determining unit is equal to or less than a predetermined number. Calculate the amount of consumption. The predetermined number is 2 or 3. The photoreceptor is made of amorphous silicon. The toner consumption calculation unit calculates, as the toner consumption, a value obtained by multiplying a weighting coefficient that defines the image density of an image determined as an image other than a character by the image determination unit as a standard. The toner consumption amount calculation unit is configured such that the toner consumption amount of the image determined to be a character image by the image determination unit is 2 dots when the dot continuity determined by the dot continuity determination unit is 2 dots, 2 or 2 Toner consumption is calculated by multiplying by a larger coefficient in the order of cases other than 3 dots.

  According to such an image forming apparatus, a character image and an image other than a character image are discriminated from input image data, the degree of dot continuity is discriminated also in pixels constituting the edge of the character image, The amount of toner consumption is calculated according to the degree of continuity. Therefore, according to such an image forming apparatus, the toner consumption amount can be accurately calculated.

1 is a schematic diagram showing an external appearance of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. 1 is a block diagram illustrating a configuration of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. It is an external view which shows the schematic structure of an operation part. FIG. 2 is an external view illustrating a schematic configuration of an image forming unit. FIG. 3 is an external view illustrating a schematic configuration of a toner concentration detection sensor. FIG. 6 is a diagram illustrating a relationship between an electric field intensity in the vicinity of the surface of the photoreceptor and a toner adhesion amount on the surface of the transfer belt at a corresponding position. 6 is a flowchart showing the contents of processing when calculating the toner consumption amount of an image to be formed using the digital multi-function peripheral according to one embodiment of the present invention. It is a figure which shows the case where pattern matching is performed and the continuity of a dot is discriminate | determined. It is a figure which shows the case where pattern matching is performed and the continuity of a dot is discriminate | determined.

  Embodiments of the present invention will be described below. FIG. 1 is a schematic diagram showing an external appearance of a digital multifunction peripheral when an image forming apparatus according to an embodiment of the present invention is applied to the digital multifunction peripheral. FIG. 2 is a block diagram showing a configuration of the digital multifunction peripheral when the image forming apparatus according to the embodiment of the present invention is applied to the digital multifunction peripheral.

  Referring to FIGS. 1 and 2, the digital multifunction peripheral 11 includes a control unit 12, an operation unit 13, an image reading unit 14, an image forming unit 15, a paper setting unit 19, a discharge tray 30, and a storage. A hard disk 16, a facsimile communication unit 17, and a network interface unit 18 for connecting to a network 25.

  The control unit 12 controls the entire digital multi-function peripheral 11. The operation unit 13 includes a display screen 21 that displays information transmitted from the digital multifunction peripheral 11 side and user input contents. The operation unit 13 inputs image forming conditions such as the number of copies to be printed and gradation, and power on / off. The image reading unit 14 includes an ADF (Auto Document Feeder) 22 as a document transport device that transports a document set at the set position to the read position. The image reading unit 14 reads an image of a document set on the ADF 22 or the mounting table. The paper setting unit 19 includes a manual feed tray 28 for manually setting paper and a paper feed cassette group 29 that can store a plurality of different sizes of paper. The paper setting unit 19 sets paper to be supplied to the image forming unit 15. The image forming unit 15 forms an image on the conveyed paper based on the image read by the image reading unit 14 and the image data transmitted via the network 25. The sheet on which the image is formed by the image forming unit 15 is discharged to the discharge tray 30. The hard disk 16 stores transmitted image data, input image forming conditions, and the like. The facsimile communication unit 17 is connected to the public line 24 and performs facsimile transmission and facsimile reception.

  The digital multi-function peripheral 11 includes a DRAM (Dynamic Random Access Memory) for writing and reading image data, and the illustration and description thereof are omitted. In addition, arrows in FIG. 2 indicate the flow of data regarding control signals, control, and images. As shown in FIG. 1, in this embodiment, the sheet cassette group 29 includes three sheet cassettes 23a, 23b, and 23c.

  The digital multifunction machine 11 operates as a copying machine by forming an image in the image forming unit 15 using the original read by the image reading unit 14. Further, the digital multifunction peripheral 11 forms an image in the image forming unit 15 and prints it on a sheet using image data transmitted from the computers 26a, 26b, and 26c connected to the network 25 through the network interface unit 18. It works as a printer. That is, the image forming unit 15 operates as a printing unit that prints the requested image. The digital multifunction machine 11 forms an image in the image forming unit 15 through the DRAM using the image data transmitted from the public line 24 through the facsimile communication unit 17 and is read by the image reading unit 14. By transmitting the image data of the original document to the public line 24 through the facsimile communication unit 17, the facsimile apparatus operates. The digital multifunction machine 11 has a plurality of functions such as a copying function, a printer function, and a facsimile function regarding image processing. Further, each function has functions that can be set in detail.

  An image forming system 27 including a digital multifunction peripheral 11 according to an embodiment of the present invention includes a digital multifunction peripheral 11 having the above-described configuration and a plurality of computers 26 a and 26 b connected to the digital multifunction peripheral 11 via a network 25. 26c. In this embodiment, three computers 26a to 26c are shown. Each of the computers 26 a to 26 c can print by making a print request to the digital multi-function peripheral 11 via the network 25. The digital multi-function peripheral 11 and the computers 26a to 26c may be connected by wire using a LAN (Local Area Network) cable or the like, or may be connected wirelessly. A configuration in which a digital multifunction peripheral or a server is connected may be used.

  Next, the configuration of the operation unit 13 described above will be described in more detail. FIG. 3 is an external view showing a schematic configuration of the operation unit 13. Referring to FIG. 3, the operation unit 13 includes a numeric keypad 31 for inputting numbers from 0 to 9 for inputting the number of copies to be printed, and symbols of “*” and “#”, and start of printing and facsimile transmission. A start key 32 for instructing the start of the printer, a power key 33 for inputting power on / off of the digital multifunction device 11, a menu key 34 for instructing selection of a printer function, a copy function, etc. of the digital multifunction device 11, A registration key 35 for instructing image forming conditions and user registration, a reset key 36 for canceling the contents of an instruction input by the user using the numeric keypad 31 and the like, and the display screen 21 described above are included. The display screen 21 has a liquid crystal touch panel function, and allows the user to input image forming conditions and the like from the display screen 21 and select a function by pressing with a user's finger.

  Next, the configuration of the image forming unit 15 provided in the digital multifunction peripheral 11 will be described in more detail. FIG. 4 is a cross-sectional view showing a schematic configuration of the digital multi-function peripheral 11 according to the embodiment of the present invention. From the viewpoint of easy understanding, the members are not hatched in FIG. FIG. 4 is a cross-sectional view of the digital multifunction machine 11 cut along a plane extending in the vertical direction.

  Referring to FIG. 4, image forming unit 15 includes photoconductors 41a, 41b, 41c and 41d made of amorphous silicon, and four image forming units 42a corresponding to four colors of yellow, magenta, cyan and black. , 42b, 42c, and 42d as exposure units that respectively expose the four image forming units 42a to 42d based on the image read by the image reading unit 14 and image data input from the outside. LSU (Laser Scanner Unit) 44 and a transfer belt 45 as an intermediate transfer member that is temporarily transferred before a visible image formed by toners formed by the image forming units 42a to 42d is transferred to a sheet, and a transfer belt 45 A transfer belt cleaning unit 47 for removing the toner remaining on the top with a blade or the like. With. The LSU 44 is schematically indicated by a one-dot chain line. The transfer belt cleaning unit 47 is also schematically shown. The image forming unit 15 is a so-called four-tandem development method. The toner consumed by the image forming units 42a to 42d is supplied to the image forming units 42a to 42d from a replaceable toner container (not shown) as needed.

The transfer belt 45 is endless, and is a visible image formed by image forming units 42a to 42d of four colors of yellow, magenta, cyan, and black while being rotated in one direction by a driven roller 46a and a driving roller 46b. Is transcribed. Rotational direction of the transfer belt 45 is indicated by an arrow D ₁ of the in FIG. In the rotation direction of the transfer belt 45, among the image forming units 42a to 42d, the yellow image forming unit 42a is disposed on the most upstream side, and the black image forming unit 42d is disposed on the most downstream side. . The transfer belt cleaning unit 47 is disposed upstream of the yellow image forming unit 42a.

  The visible image by the toner transferred onto the transfer belt 45 is transferred to the conveyed paper and is fixed on the paper by a fixing unit (not shown). After fixing, the sheet is discharged out of the digital multifunction peripheral 11, specifically, the discharge tray 30. After the visible image by the toner is transferred to the paper, the toner remaining on the transfer belt 45 is removed by the transfer belt cleaning unit 47. Then, the next image formation is performed.

  The digital multifunction peripheral 11 can perform monochrome printing using only the black image forming unit 42d. The digital multifunction peripheral 11 can perform color printing using at least one of a yellow image forming unit 42a, a magenta image forming unit 42b, and a cyan image forming unit 42c.

  The digital multifunction machine 11 includes a toner density adjusting unit 51 that adjusts the density of a visible image with toner at a predetermined timing. The predetermined timing is, for example, the timing at which the environment has changed, specifically, it is detected that the temperature value and the humidity value in the environment where the digital multi-function peripheral 11 is installed have exceeded a predetermined value. It is timing. The predetermined timing is, for example, a timing at which a member of the digital multi-function peripheral 11 changes over time, specifically, a timing at which the number of image formations is every 1000 sheets, an engine drive of the digital multi-function peripheral 11 For example, the timing when the time reaches a predetermined time. At such timing, the density of the visible image by the toner formed on the transfer belt 45 is adjusted.

  The toner density adjusting unit 51 includes a pattern image forming unit and a toner density detecting sensor 52. First, the pattern image forming unit irradiates light onto the photoconductors 41a to 41d by the LSU 44, which is an exposure unit, to form electrostatic latent images of pattern images on the photoconductors 41a to 41d. Then, the image forming units 42a to 42d supply toner to the electrostatic latent image of the pattern image to form a visible image using the toner of the pattern image. Thereafter, the visible image of the pattern image using toner is transferred onto the transfer belt 45, and the visible image of the pattern image using toner is formed on the transfer belt 45.

  The toner density detection sensor 52 detects the toner density of the pattern image formed by the pattern image forming unit. Here, the configuration of the toner concentration detection sensor 52 will be briefly described. FIG. 5 is a schematic diagram showing the configuration of the toner concentration detection sensor 52. In FIG. 4, the toner concentration detection sensor 52 is schematically indicated by a two-dot chain line.

  1 to 5, the toner density detection sensor 52 is disposed on the downstream side of the black image forming unit 42 d in the rotation direction of the transfer belt 45. The toner density detection sensor 52 receives light by a light emitting element 53a that irradiates light on the surface 48 side of the transfer belt 45, a light receiving element 53b that receives reflected light reflected from the surface 48 side of the transfer belt 45, and a light receiving element 53b. And a toner concentration deriving unit 54 for deriving the toner concentration from the amount of reflected light. In this embodiment, the light emitting element 53 a and the light receiving element 53 b are installed so as to be symmetrical with respect to a plane 55 extending in a direction perpendicular to the surface of the transfer belt 45. That is, the light receiving element 53b is provided at a position for receiving regular reflection light with respect to the light emitted by the light emitting element 53a. As an example of the light emitting element 53a, specifically, an infrared light emitting diode that irradiates infrared light is employed. As an example of the light receiving element 53b, specifically, an infrared light receiving element is employed.

Emitting element 53a is towards the visible image 49 by the surface 48 or the toner of the transfer belt 45 is irradiated with light 56a such infrared light to the left obliquely upward direction indicated by arrow E ₁ in FIG. When the visible image 49 of toner is not formed, the light emitting element 53a emits light 56a toward the surface 48 of the transfer belt 45.

The light receiving element 53b is either one of the reflected light 56b from the surface 48 of the reflected light 56b and the transfer belt 45 from the visible image 49 by the toner toward the lower left direction indicated by the arrow E ₂ in FIG. 5 or toner, The reflected light 56b from both the visible image 49 and the surface 48 of the transfer belt 45 is received. If the visible image 49 made of toner completely covers the surface 48 of the transfer belt 45, only the reflected light 56b from the visible image 49 made of toner is received. If the visible image 49 made of toner is not formed on the surface 48 of the transfer belt 45, only the reflected light 56b from the surface 48 of the transfer belt 45 is received. If the visible image 49 by toner does not completely cover the surface 48 of the transfer belt 45 and the amount of toner in the visible image 49 by toner is small, reflection from both the visible image 49 by toner and the surface 48 of the transfer belt 45 is performed. The light 56b is received.

Toner concentration detecting sensor 52, the transfer belt 45 to a visible image 49 is formed by the toner on the surface 48 is irradiated with light 56a in the direction indicated by arrow E ₁ in FIG. The light 56 a strikes and reflects either the visible image 49 with toner and the surface 48 of the transfer belt 45, or both the visible image 49 with toner and the surface 48 of the transfer belt 45. The reflected reflected light 56b is received by the light receiving element 53b. The light receiving elements 53b each output a current corresponding to the amount of received light. The toner concentration deriving unit 54 converts the current output by the light receiving element 53b into a voltage value. Then, the toner density is derived based on this voltage value. In this way, the toner concentration detection sensor 52 detects the toner concentration.

  Using such a toner density detection sensor 52, the toner density is adjusted. Here, the toner density adjusting unit 51 separately adjusts the toner density of the character image and the toner density of an image other than the character image, for example, a photographic image. That is, when adjusting the toner density of the character image, a pattern image of the character image is formed, and the toner density of the formed pattern image is detected by the toner density detection sensor 52 to adjust the toner density. On the other hand, when adjusting the toner density of an image other than a character image, for example, a photographic image, a pattern image of the photographic image is formed, and the toner density of the formed pattern image is detected by the toner density detection sensor 52. Adjust the toner density.

  Next, the state of toner adhesion on the surfaces of the photoconductors 41a to 41d when forming a pattern image of a character image, that is, the surface 48 of the transfer belt 45 to which the toner is transferred from the surfaces of the photoconductors 41a to 41d. explain. FIG. 6 is a graph showing the relationship between the electric field strength in the vicinity of the surfaces of the photoconductors 41a to 41d and the amount of toner attached to the surface 48 of the transfer belt 45 at the corresponding position. In FIG. 6, the vertical axis represents the electric field strength and the amount of toner attached to the surface 48 of the transfer belt 45, and the horizontal axis represents the areas exposed to the photoconductors 41 a to 41 d. A solid line 57 indicates the toner adhesion amount. The vertical axis indicates that the electric field strength is higher and the toner adhesion amount is increased toward the upper side. The exposed areas are indicated by areas 58a and 58c in FIG. On the other hand, the unexposed area is indicated by an area 58b in FIG. 6 sandwiched between the area 58a and the area 58c.

  Referring to FIG. 6, when exposure is performed in region 58a and region 58c and non-exposure is performed in region 58b, it is ideal that an electric field strength as indicated by solid line 59a appears. That is, at the boundary between the exposure region 58a and the non-exposure region 58b, and the boundary between the exposure region 58c and the non-exposure region 58b, the electric field strength greatly changes without causing an extreme decrease or increase in the electric field strength near the boundary. Is ideal.

However, due to the influence of the edge effect or the like, the electric field strength actually becomes as shown by the solid line 59b. That is, the electric field strength is extremely low at the point P ₁ slightly on the exposure area 58a side from the point P _{2 at} the boundary between the exposure area 58a and the non-exposure area 58b. Then, in the exposed areas 58a slightly unexposed regions 58b side becomes a point P ₃ than the point P ₂ of the boundary between the unexposed region 58b, the electric field strength is extremely high. Further, the P ₇ that a slight exposure area 58c side from the point P ₆ in the boundary between the exposed region 58c and unexposed regions 58b, the electric field strength is extremely low. Then, the P ₅ that becomes slightly non-exposed regions 58b side from the point P ₆ in the boundary between the exposed region 58c and unexposed regions 58b, the electric field strength is extremely high. In the region between points P ₃ and the point P _5, the electric field strength is slightly lower than the position of the point P ₃ and the point P _5.

Here, depending on the environment in which the digital multi-function peripheral 11 is installed, in the case of a character image, that is, an image having a narrow space between the point P ₃ and the point P ₅ , the electric field strength becomes the highest with respect to the toner adhesion amount. the influence of the point _{P 3} and the point _{P 5,} the maximum at the center and becomes a point _{P 4} between the points _{P 3} and the point _{P 5.} That is, the toner adheres so as to gradually increase from the position of the points P ₃ and P ₅ toward the point P ₄ . When such a phenomenon occurs, more toner than necessary is consumed per unit area. That is, when a character image is formed despite the fact that it corresponds to the same area, more toner is consumed than when an image other than a character image is formed. Therefore, in order to accurately calculate the toner consumption amount, it is required to accurately determine whether an image to be formed is a character image or an image other than a character image. Note that the character image is composed of pixels having a relatively high density compared to an image other than the character image, for example, a photographic image, so that the difference from the white area that is the background can be easily identified. Is.

  Further, among the character images, the amount of toner adhesion also varies depending on the degree of dot continuity in the pixels constituting the edge. That is, the toner consumption varies depending on the degree of dot continuity. Specifically, until the dot continuity reaches a certain number, more toner adheres and more toner is consumed accordingly. This will be described later.

  In addition, the digital multifunction peripheral 11 includes a toner consumption amount calculation unit 39 that calculates a toner consumption amount when a visible image is formed with toner by the image forming units 42a to 42d. By providing the toner consumption amount calculation unit 39, the digital multi-function peripheral 11 can manage the remaining number of printable sheets more accurately.

  Next, a case where the toner consumption amount of the image to be formed is calculated by the digital multifunction peripheral 11 according to the embodiment of the present invention will be described. FIG. 7 is a flowchart showing the contents of processing when calculating the toner consumption amount of the image to be formed using the digital multifunction peripheral 11 according to the embodiment of the present invention.

  Referring to FIG. 7, the digital multifunction peripheral 11 inputs image data from the computer 26a (in FIG. 7, step S11, hereinafter, “step” is omitted). Specifically, it accepts input of image data from the computer 26a and accepts a print request based on the image data. That is, a so-called print job request is accepted. Here, the control unit 12 operates as an input unit for inputting image data. In this case, image density data of an image to be formed is also input according to a user request.

  Thereafter, the digital multi-function peripheral 11 performs image processing such as enlargement or reduction requested by the user on the input image data to generate image data (S12).

  Next, the digital multi-function peripheral 11 determines image attributes for the generated image data (S13). For determining the image attribute, the image data requested to be printed is analyzed, and a character image and an image other than the character image are determined from the image data. Here, the control unit 12 operates as a character image determination unit that determines a character image and an image other than the character image from the image data input by the input unit.

  Thereafter, with respect to the determined character image, the degree of dot continuity is determined for the pixels constituting the edge of the character image (S14). Here, the control unit 12 operates as a dot continuity determination unit.

  FIG. 8 is a diagram illustrating a case in which pattern matching is performed to determine the degree of dot continuity. In FIG. 8, in the pixels constituting the edge 61a of the discriminated character image, the dot 62b located on the left side of the dot 62a on which the image is formed is the dot to be discriminated. It is assumed that the dots 62a and 62b are arranged in the main scanning direction. The same applies to the edges 61a, 61b, 66a, 66b, and 66c of the character image shown in FIGS.

  If the dot 62b is a dot on which an image is formed, the dot continuity in the pixels constituting the edge 61a of the character image is 2 dots. On the other hand, if the dot 62b is a dot on which no image is formed, the degree of dot continuity in the pixels constituting the edge 61a of the character image is 1 dot.

  In FIG. 8, in the pixels constituting the edge 61b of the determined character image, the dot 63a located on the right side of the dot 63b on which the image is formed becomes the determination target dot. If the dot 63a is a dot on which an image is formed, the degree of dot continuity in the pixels constituting the edge 61b of the character image is 2 dots. On the other hand, if the dot 63a is a dot on which no image is formed, the degree of dot continuity in the pixels constituting the edge 61b of the character image is 1 dot.

  FIG. 9 is also a diagram illustrating a case where pattern matching is performed to determine the degree of dot continuity. In FIG. 9, in the pixels constituting the edge 66a of the discriminated character image, the dot 67c located to the left of the adjacent dots 67a and 67b on which the image is formed is the dot to be discriminated. If the dot 67c is a dot on which an image is formed, the degree of dot continuity in the pixels constituting the edge 66a of the character image is 3 dots. On the other hand, if the dot 67c is not a dot on which an image is formed, the degree of dot continuity in the pixels constituting the edge 66a of the character image is 2 dots.

  In FIG. 9, in the pixels constituting the edge 66b of the determined character image, the dot 68b positioned between the dot 68a and the dot 68c on which the image is formed is also a determination target dot. If the dot 68b is a dot on which an image is formed, the degree of dot continuity in the pixels constituting the edge 66b of the character image is 3 dots. On the other hand, if the dot 68b is a dot on which no image is formed, the degree of dot continuity in the pixels constituting the edge 66b of the character image is 1 dot. That is, it is determined that the dots are not continuous.

  Further, in FIG. 9, in the pixels constituting the edge 66c of the determined character image, the dot 69a located on the right side of the adjacent dots 69c and 69b on which the image is formed becomes the determination target dot. If the dot 69a is a dot on which an image is formed, the degree of dot continuity in the pixels constituting the edge 66c of the character image is 3 dots. On the other hand, if the dot 69a is not a dot on which an image is formed, the degree of dot continuity in the pixels constituting the edge 66c of the character image is 2 dots.

  In this way, the degree of dot continuity in the pixels constituting the edges 61a, 61b, 66a, 66b, 66c of the character image is determined. If the degree of dot continuity in the pixels constituting the edge 61a of the character image is determined, toner consumption is calculated according to the degree of dot continuity (S15). In this case, when the image density in an image other than characters is designated as “normal”, the standard “1.0” is set, and a value obtained by multiplying the standard “1.0” by a weighting coefficient is used as the toner. Consumption amount. Table 1 and Table 2 show the weighting according to the character image, the image other than the character image, and the dot continuity.

  When calculating the toner consumption amount, the toner consumption amount originally calculated for the pixel determined as a character image and the pixel determined as other than the character image according to the image density required for output and the degree of continuity of dots. Is multiplied by the coefficients in Tables 1 and 2.

  Specifically, when “darker” of the image density is input for a pixel determined as a character image, a coefficient of “1.85” is multiplied for a pixel having a dot continuity level of 2 dots. A pixel having a dot continuity of 3 dots is multiplied by a coefficient of “1.7”. A pixel having a dot continuity other than 2 dots and 3 dots, that is, a pixel of 1 dot or 4 dots or more is multiplied by a coefficient of “1.5”.

  When “normal” image density is input, a coefficient of “1.8” is multiplied for a pixel having a dot continuity of 2 dots. A pixel with a dot continuity of 3 dots is multiplied by a coefficient of “1.65”. For pixels other than 2 dots and 3 dots, the coefficient of “1.45” is multiplied.

  When “light” of the image density is input, a coefficient of “1.7” is multiplied for a pixel having a dot continuity of 2 dots. A pixel having a dot continuity of 3 dots is multiplied by a coefficient of “1.6”. For pixels with dot continuity other than 2 dots and 3 dots, a coefficient of “1.4” is multiplied.

  Further, when “darker” of the image density is inputted to the pixels determined as other than the character image, the coefficient “1.1” is multiplied uniformly, that is, irrespective of the degree of dot continuity. When “normal” of the image density is input, a coefficient of “1.0” is uniformly multiplied. That is, it is used as it is. When “thin” image density is input, a coefficient “0.9” is uniformly multiplied.

  Thus, the toner consumption amount in the entire image data generated by multiplying by the coefficient is calculated. Then, based on the input image data, the image forming unit 15 forms an image (S16). That is, the visible image of the toner transferred to the transfer belt 45 is transferred to a recording medium such as paper, and an image based on the image data is formed and output on the paper. Here, the image forming unit 15 and the like operate as an output unit.

  Note that the calculated toner consumption amount is accumulated and stored in the hard disk 16, for example. For example, it is used as an index for determining how many sheets can be printed in the digital multi-function peripheral 11. For this index, for example, an approximate value can be displayed on the display screen 21. It is also used to measure the timing of toner container replacement.

  According to such a digital multi-function peripheral 11, a character image and an image other than a character image are discriminated from input image data, and the degree of dot continuity is discriminated also in pixels constituting the edge of the character image. The toner consumption is calculated according to the degree of dot continuity. Therefore, according to such a digital multifunction machine 11, the toner consumption amount can be accurately calculated.

  In this case, if the dot continuity determined by the dot continuity determination unit is equal to or less than a predetermined number, the amount of toner consumption is set so that more toner is consumed than dots having a dot continuity greater than the predetermined number. Since it is calculated, it is possible to calculate the toner consumption more accurately. Specifically, the predetermined number is 2 or 3. That is, the dot continuity is determined as 2 or 3. By doing so, it is possible to calculate the toner consumption more accurately. In the above-described embodiment, the coefficient may be multiplied also for the portion where the dot continuity is 4 dots or more.

  In addition, when calculating the toner consumption amount in the toner consumption amount calculation unit, the toner consumption amount may be calculated by reflecting the adjustment by the toner density adjustment unit. That is, for example, after adjustment by the toner density adjustment unit, the numerical value of weighting is corrected. By doing so, it is possible to calculate the toner consumption amount according to the actual machine, and it is possible to calculate the toner consumption amount more accurately.

  In the above embodiment, the degree of dot continuity is determined by pattern matching. However, the present invention is not limited to this. For example, the degree of dot continuity may be determined by another method such as an image processing filter. Good.

  In the above embodiment, the image data is input from the computer 26a to the digital multi-function peripheral 11. However, the present invention is not limited to this. May be read and image data may be input. In this case, the required image density is input by the user from the display screen 21 of the operation unit 13 or the like.

  In the above embodiment, the dot continuity is determined for the dots arranged in the main scanning direction. However, the present invention is not limited to this, and the dot continuity is determined for the dots arranged in the sub-scanning direction. It may be determined.

  In the above embodiment, the amorphous silicon is used as the photoconductor. However, the present invention is not limited to this, and the photoconductor is also applicable to a case where a photoconductor of another material is used.

  It should be understood that the embodiments and examples disclosed herein are illustrative in all respects and are not restrictive in any respect. The scope of the present invention is defined by the scope of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.

  The image forming apparatus according to the present invention is particularly effectively used when accurate calculation of toner consumption is required.

  DESCRIPTION OF SYMBOLS 11 Digital multifunction device, 12 Control part, 13 Operation part, 14 Image reading part, 15 Image formation part, 16 Hard disk, 17 Facsimile communication part, 18 Network interface part, 19 Paper setting part, 21 Display screen, 22 ADF, 23a, 23b, 23c Paper cassette, 24 Public line, 25 Network, 26a, 26b, 26c Computer, 27 Image forming system, 28 Manual feed tray, 29 Paper feed cassette group, 30 Eject tray, 31 Numeric keypad, 32 Start key, 33 Power key , 34 Menu key, 35 Registration key, 36 Reset key, 39 Toner consumption calculator, 41a, 41b, 41c, 41d Photoconductor, 42a, 42b, 42c, 42d Image forming unit, 43 Imager, 44 LSU, 45 Transcription bell 46a, driven roller, 46b driving roller, 47 transfer belt cleaning unit, 48 surface, 49 visible image, 51 toner density adjusting unit, 52 toner density detecting sensor, 53a light emitting element, 53b light receiving element, 54 toner density deriving part, 55 plane 56a, 56b light, 57, 59a, 59b solid line, 58a, 58b, 58c region, 61a, 61b, 66a, 66b, 66c edge, 62a, 62b, 63a, 63b, 67a, 67b, 67c, 68a, 68b, 68c , 69a, 69b, 69c dots.

Claims (4)

A photoreceptor,
An input unit for inputting image data;
An exposure unit that irradiates the photosensitive member with light and forms an electrostatic latent image on the photosensitive member based on the image data input by the input unit;
An image forming unit that supplies toner to the electrostatic latent image formed by the exposure unit to form a visible image on the photosensitive member with the toner;
A transfer body for transferring a visible image of the toner formed by the image forming unit;
An output unit that transfers a visible image of the toner transferred to the transfer body to a recording medium and forms and outputs an image based on the image data on the recording medium;
An image discriminating unit for discriminating a character image and an image other than a character image from the image data input by the input unit;
A dot continuity determination unit that determines the continuity of dots of pixels that constitute the edge of the character image determined by the image determination unit;
A toner consumption amount calculation unit that calculates a consumption amount of the toner when the visible image is formed by the image forming unit according to the degree of continuity of the dots determined by the dot continuity determination unit. ,
The toner consumption calculation unit consumes more toner than dots having a dot continuity greater than a predetermined number if the dot continuity determined by the dot continuity determination unit is equal to or less than a predetermined number. Calculate the toner consumption so that
The predetermined number is 2 or 3;
The photoreceptor is made of amorphous silicon,
The toner consumption amount calculation unit calculates, as the toner consumption amount, a value obtained by multiplying a weighting coefficient that defines an image density of an image determined as an image other than the character by the image determination unit as a standard,
The toner consumption amount calculation unit is configured such that, for the toner consumption amount of the image determined to be the character image by the image determination unit, the dot continuity determined by the dot continuity determination unit is 2 dots. In the case of the image forming apparatus, the toner consumption is calculated by multiplying the coefficient in the order of the case other than 2 or 3 dots . The exposure unit irradiates the light onto the photoconductor to form an electrostatic latent image of a pattern image on the photoconductor, and supplies the toner to the electrostatic latent image of the pattern image by the image forming unit. Forming a visible image of the pattern image with the toner, transferring the visible image of the pattern image with the toner onto the transfer body, and forming a visible image of the pattern image with the toner on the transfer body An image forming unit, and a toner concentration detection sensor that detects the toner concentration of the pattern image formed by the pattern image forming unit, and at a predetermined timing, the visible image of the visible image formed by the toner formed on the transfer body. A toner density adjusting unit for adjusting the toner density;
The image forming apparatus according to claim 1 , wherein the toner consumption amount calculation unit calculates the toner consumption amount by reflecting the adjustment by the toner density adjustment unit. The toner consumption amount calculation unit calculates a toner consumption amount corresponding to a pixel constituting the character image determined by the image determination unit from a toner consumption amount corresponding to a pixel constituting an image other than the character image. The image forming apparatus according to claim 1 , wherein the consumption amount of the toner is calculated so as to be increased. The dot successive degree determination unit, by pattern matching, determines the continuous degree of dots constituting an edge portion of the character image, the image forming apparatus according to any one of claims 1-3.

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