JP5538321B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, or a facsimile using an electrophotographic process, and more particularly to an image forming apparatus including a detachable toner storage container that supplies toner to a developing device.

  In a conventional developing unit of an image forming apparatus, a certain amount of toner is filled in the developing unit for easy maintenance, and the developing unit is replaced when the toner runs out. However, the developing unit cannot be replaced frequently from an economic point of view, and the toner volume must be increased in order to form an image to some extent. Therefore, it is difficult to reduce the size of the image forming apparatus including the developing unit.

  Therefore, in order to reduce the size of the developing unit, a method of supplying toner from the outside using a replaceable toner container such as a toner container or a toner cartridge has been proposed. In this system, the user is prompted to replace the toner container by displaying that the remaining amount of toner stored in the toner container is empty (hereinafter referred to as toner end).

  However, if the display of the toner end is suddenly performed, the user may not be able to use the image forming apparatus when it takes time to prepare the replacement toner container. Therefore, a state near the toner end (hereinafter referred to as the near end) is set and displayed before displaying the toner end, and the near end display secures time for the user to prepare a replacement toner container.

  For example, in Patent Document 1, an image is divided into a predetermined size, and an accurate toner consumption amount is calculated by weighting the total density or the total number of gradations of the divided areas, and based on the toner consumption amount. An image forming apparatus is disclosed that shifts to a toner save mode when the remaining amount of toner in the toner cartridge (toner container) calculated in this way becomes equal to or less than a predetermined value set in advance.

  Further, in Patent Document 1, a predetermined number of days required for the preparation of the toner cartridge by the user is set in advance, and the remaining amount of toner becomes equal to or less than a value obtained by multiplying the average toner consumption per day by the predetermined number of days. It is also described that by executing the toner save mode sometimes, it is possible to secure at least the number of working days required until a replacement cartridge is obtained.

JP 2006-251180 A

  However, as in Patent Document 1, when the start time of the toner save mode is changed based on the average toner consumption per day and the set number of days, the toner save mode is started when the set number of days is short. At this point, the remaining amount of toner in the toner container may have decreased considerably and may be below the minimum toner amount necessary to maintain image quality. For this reason, there is a possibility that image density lowering or image quality lowering such as density unevenness may occur after or before the start of the toner save mode.

  In view of the above problems, the present invention makes it possible to accurately grasp the replacement timing of a toner container while saving toner consumption within a range that does not impair image quality when the amount of toner in the toner container decreases. An object of the present invention is to provide a simple image forming apparatus.

  To achieve the above object, the present invention provides an image input unit for inputting image information to be printed, a developing device for forming a toner image corresponding to an electrostatic latent image on the surface of the image carrier, and replenishing the developing device. A replaceable toner storage container for storing toner to be stored, a toner remaining amount detecting means capable of detecting that the toner remaining amount in the toner storage container has become equal to or less than a predetermined amount, and immediately after the start of use of the image forming apparatus Average toner consumption calculating means for calculating an average toner consumption per image and an average toner consumption per day based on the cumulative number of printed sheets and the cumulative toner consumption, and the amount of toner remaining in the toner container And a control unit capable of executing a toner save mode that suppresses toner consumption when compared with that during normal printing, when the amount of toner remaining in the toner container is low. Display control means for displaying whether or not the toner save mode has been executed, and whether or not to execute the toner save mode, and a date and time of replacement of the toner container when the toner save mode is executed, The means in the toner save mode is based on the replacement date and time information of the toner container inputted by the display input means and the average toner consumption per day calculated by the average toner consumption calculation means. It is characterized by changing the degree of suppression of toner consumption.

  According to the present invention, in the image forming apparatus configured as described above, the image forming apparatus includes an image attribute determining unit that determines an attribute of the image information input from the image input unit, and the control unit determines the image determined by the image attribute determining unit. The degree of suppression of toner consumption in the toner save mode is changed according to the attribute.

  According to the present invention, in the image forming apparatus configured as described above, the display input unit is a character that reduces a degree of suppression of toner consumption compared to an image image when the image information input from the image input unit is a character image. It is possible to selectively input a priority mode and an image priority mode that lowers the degree of toner consumption suppression compared to a character image when the image information input from the image input unit is an image image. Yes.

  According to the present invention, in the image forming apparatus having the above-described configuration, the display input unit displays a range of replacement date and time of the toner container that can be input when the toner save mode is executed.

  According to the present invention, in the image forming apparatus having the above-described configuration, the control unit stops execution of the toner save mode when the replacement date / time information closer to the replacement date / time range displayed on the display / input unit is input. It is characterized by doing.

  According to the present invention, in the image forming apparatus configured as described above, the control unit prompts the user to re-enter the replacement date and time when the replacement date and time information before the replacement date and time range displayed on the display and input unit is input. It is characterized by displaying.

  According to the present invention, in the image forming apparatus having the above-described configuration, the control unit changes the remaining amount of toner in the toner storage container due to a printing operation after executing the toner save mode, and the input toner storage container. The degree of suppression of toner consumption in the toner save mode is recalculated based on the change in the period until the replacement date and time.

  According to the first configuration of the present invention, the degree of suppression of the toner consumption amount during the toner save mode is changed based on the replacement date and time information of the toner container input by the user and the average toner consumption amount per day. Therefore, the toner save mode is executed so that the toner is consumed just at the input replacement date and time. Therefore, the user can accurately grasp the replacement date and time of the toner container. Further, since the toner save mode is executed from the near-end state of the toner container set in consideration of the usability of the image forming apparatus and the image quality, the toner is more than necessary at the start of the toner save mode or before the start. There is no risk of a decrease, and it is possible to prevent the occurrence of a decrease in image density or density unevenness.

  According to the second configuration of the present invention, in the image forming apparatus having the first configuration, the image attribute determined by the image attribute determination means is a character image or an image image such as a photograph or graphic. Accordingly, by changing the degree of suppression of toner consumption during the toner save mode, the toner save mode can be executed without losing the visibility of the character image and the gradation of the image image as much as possible.

  Further, according to the third configuration of the present invention, in the image forming apparatus having the second configuration, when the image information is a character image, the character priority mode that lowers the degree of suppression of the toner consumption compared to the image image; When the image information is an image image, it is possible to selectively input an image priority mode that lowers the degree of suppression of toner consumption compared to a character image. The toner save mode can be executed to increase the toner save mode.

  According to the fourth configuration of the present invention, in the image forming apparatus having any one of the first to third configurations, the range of replacement date and time of the toner container that can be input when the toner save mode is executed is set. By displaying on the display input means, it is possible to suppress mistakes in inputting the replacement date.

  According to the fifth configuration of the present invention, in the image forming apparatus having the fourth configuration, the toner save mode is selected when replacement date / time information closer to the replacement date / time range displayed on the display input means is input. By stopping the execution of the above, when the toner container can be replaced at an early stage, a high-quality image can be output without performing the toner save mode.

  According to the sixth configuration of the present invention, in the image forming apparatus having the fourth or fifth configuration, when the replacement date / time information prior to the replacement date / time range displayed on the display input unit is input. By displaying a message prompting the user to re-enter the replacement date, it is possible to avoid a problem that the remaining amount of toner becomes empty before the input replacement date and time, and to eliminate the possibility that the user forgets to re-enter the replacement date.

  According to the seventh configuration of the present invention, in the image forming apparatus having any one of the first to sixth configurations, the remaining amount of toner in the toner container by the printing operation after the toner save mode is executed. By recalculating the degree of suppression of toner consumption in the toner save mode based on the change and the change in the period until the replacement date of the toner storage container, the input replacement date and time in the toner storage container It is possible to accurately match the timing when the remaining amount of toner becomes empty.

1 is a schematic cross-sectional view showing the overall configuration of an image forming apparatus 100 according to the present invention. Side surface sectional view which shows the example of 1 structure of the developing device 3 used for the image forming apparatus 100 of this invention. Plan sectional drawing which shows one structural example of the stirring part in the image development apparatus 3 of this invention. The figure which shows an example of the bias waveform applied to a developing roller and a magnetic roller Side sectional view schematically showing the toner container 6 1 is a block diagram showing a control path of an image forming apparatus 100 according to the present invention. The figure which shows an example of the gamma correction table used for toner save mode 6 is a flowchart illustrating an example of toner save mode control executed in the image forming apparatus of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of the image forming apparatus of the present invention. In FIG. 1, an image forming apparatus 53 (a monochrome multifunction device is shown as an example here) is provided with an image forming portion 53 that forms a monochrome image by charging, exposing, developing, and transferring processes.

  Next, the image forming unit 53 will be described. Around the photosensitive drum 1 rotatably disposed, a charging device 2 for charging the photosensitive drum 1, an exposure device (laser scanning unit or the like) 4 for exposing image information to the photosensitive drum 1, and photosensitive A developing device 3 that forms a toner image on the body drum 1 and a cleaning device 5 that removes toner remaining on the photosensitive drum 1 are disposed. Further, a static elimination device (not shown) for removing residual charges on the surface of the photosensitive drum 1 is provided on the downstream side of the cleaning device 5 with respect to the rotation direction of the photosensitive drum 1 (the direction of arrow A in FIG. 1). . An image forming process is performed on the photosensitive drum 1 while rotating the photosensitive drum 1 in the direction of arrow A.

  The paper P on which the toner image is transferred is accommodated in a paper feed cassette 10 at the lower part of the apparatus, and a nip portion between the photosensitive drum 1 and the transfer roller 9 via the paper feed roller 11 and the registration roller pair 13. It is conveyed to (transfer nip part).

  The image reading unit 20 includes a scanner lamp that illuminates the document during copying, a scanning optical system equipped with a mirror that changes the optical path of reflected light from the document, and a condensing lens that focuses the reflected light from the document to form an image. And a CCD sensor or the like (both not shown) that converts the imaged image light into an electrical signal, and reads a document image and converts it into image data.

  When performing the copying operation, the image reading unit 20 reads the image data of the document and converts it into an image signal. On the other hand, in the image forming unit 53 in the main body of the image forming apparatus 100, the photosensitive drum 1 rotating in the direction A in the drawing is uniformly charged by the charging device 2, and the original image data read by the image reading unit 20 is converted into the original image data. An electrostatic latent image is formed on the photosensitive drum 1 by the laser beam from the exposure device 4 based on this, and toner is attached to the electrostatic latent image by the developing device 3 to form a toner image. The toner is supplied to the developing device 3 from the toner container 6. On the other hand, the paper P is transported from the paper feed cassette 10 to the registration roller pair 13 via the paper feed roller 11 and the paper transport path 12.

  Then, the paper P is conveyed from the registration roller pair 13 to the nip portion between the photosensitive drum 1 and the transfer roller 9 at a predetermined timing, and the toner image formed on the surface of the photosensitive drum 1 at the nip portion is the paper P. Transcribed above. Thereafter, the toner remaining on the surface of the photosensitive drum 1 is removed by the cleaning device 5 in preparation for the subsequent formation of a new electrostatic latent image. The paper P on which the toner image is transferred is conveyed to the fixing unit 7.

  The sheet P conveyed to the fixing unit 7 is heated and pressurized when passing through the nip portion (fixing nip portion) of the pair of fixing rollers 14 to fix the toner image on the surface of the sheet P, thereby forming a predetermined image. Is done. The paper P on which the image is formed is distributed in the transport direction by the transport guide member 16 disposed in the branch portion of the paper transport path 12 through the transport roller pair 15 and is sent as it is (or sent to the reverse transport path 19 to both sides. After being copied), the sheet is discharged to the discharge tray 18 via the discharge roller pair 17.

  Specifically, the sheet conveying path 12 is bifurcated into the left and right forks on the downstream side of the conveying roller pair 15, and one path (the path branched in the right direction in FIG. 1) communicates with the discharge tray 18. ing. The other path (the path branched in the left direction in FIG. 1) is configured to communicate with the reverse conveyance path 19.

  2 is a side sectional view of the developing device 3 mounted on the image forming apparatus of the present invention, and FIG. 3 is a plan sectional view of the developing device 3 (a sectional view taken along the line XX ′ in FIG. 2). As shown in FIGS. 2 and 3, the developing device 3 includes a developing container 30 that stores a two-component developer (hereinafter also simply referred to as a developer) including toner and a magnetic carrier (hereinafter also simply referred to as a carrier). The developing container 30 is partitioned into a first stirring chamber 30b and a second stirring chamber 30c by a partition wall 30a. In the first and second agitating chambers 30b and 30c, a first agitating screw 31a and a first agitating screw 31a for charging the toner (positively charged toner) supplied from the toner container 6 (see FIG. 1) with a carrier, agitating the mixture, and charging them. Two stirring screws 31b are rotatably disposed.

  Then, the developer is agitated by the first agitating screw 31a and the second agitating screw 31b and conveyed in the axial direction (the directions of arrows B and C in FIG. 3), and the developer passages formed at both ends of the partition wall 30a. It circulates between the 1st and 2nd stirring chambers 30b and 30c via 40a and 40b. That is, a developer circulation path is formed in the developer container 30 by the first and second stirring chambers 30b and 30c and the developer passages 40a and 40b.

  The developing container 30 extends obliquely upward to the left in FIG. 2, and a magnetic roller 32 is disposed above the first stirring screw 31 a in the developing container 30, and the developing roller 33 is disposed obliquely upward to the left of the magnetic roller 32. Are arranged opposite to each other. The developing roller 33 faces the photosensitive drum 1 on the opening side (left side in FIG. 2) of the developing container 30, and the magnetic roller 32 and the developing roller 33 are clockwise in FIG. Rotate to.

  A toner concentration sensor 41 is disposed in the second stirring chamber 30c so as to face the second stirring screw 31b, and a supply port 61a (see FIG. 5) of the toner container 6 is connected to the toner supply port 30d. As shown in FIG. 3, the toner replenishing port 30d is disposed at the upstream end of the second stirring chamber 30c with respect to the developer transport direction (arrow C direction) as viewed in a plan view.

  As the toner concentration sensor 41, a magnetic permeability sensor that detects the magnetic permeability of the two-component developer in the developing container 30 is used. Here, the toner concentration is the ratio (T / C) of the toner to the magnetic carrier in the developer, and in this embodiment, the toner permeability is detected by the toner concentration sensor 41, and the detection result thereof. Is output to a control unit 90 (see FIG. 6), which will be described later. In the control unit 90, the toner density is determined from the output value of the toner density sensor 41. The control unit 90 transmits a control signal to the toner supply motor 27 (see FIG. 5) according to the determined toner density, and supplies a predetermined amount of toner into the developing container 30 from the toner supply port 30d.

  The sensor output value changes according to the toner concentration. The higher the toner concentration, the higher the ratio of toner to the magnetic carrier, and the higher the ratio of toner that does not pass magnetism, the lower the output value. On the other hand, the lower the toner concentration, the lower the ratio of toner to magnetic carrier, and the higher the ratio of magnetic carrier that passes magnetism, the higher the output value.

  The magnetic roller 32 includes a non-magnetic rotating sleeve 32a and a fixed magnet body 32b having a plurality of magnetic poles (here, five poles) contained in the rotating sleeve. In the present embodiment, the magnetic pole of the fixed magnet body 32 b has a five-pole configuration including a main pole 45, a regulation pole (head cutting pole) 46, a transport pole 47, a separation pole 48, and a pumping pole 49.

  The developing roller 33 includes a cylindrical developing sleeve 33a and a developing roller side magnetic pole 33b fixed in the developing sleeve 33a. The magnetic roller 32 and the developing roller 33 are predetermined at the facing position (opposing position). It is facing with a gap of. The developing roller side magnetic pole 33b is different in polarity from the opposing magnetic pole (main pole) 45 of the fixed magnet body 32b.

  Further, a spike cutting blade 35 is attached to the developing container 30 along the longitudinal direction of the magnetic roller 32 (direction perpendicular to the paper surface of FIG. 2), and the spike cutting blade 35 rotates in the rotation direction of the magnetic roller 32 (see FIG. 2 (clockwise direction) 2, it is positioned upstream of the opposing position of the developing roller 33 and the magnetic roller 32. A slight gap (gap) is formed between the tip of the ear cutting blade 35 and the surface of the magnetic roller 32.

  A DC voltage (hereinafter referred to as Vslv (DC)) and an AC voltage (hereinafter referred to as Vslv (AC)) are applied to the developing roller 33, and a DC voltage (hereinafter referred to as Vmag (DC)) is applied to the magnetic roller 32. And an alternating voltage (hereinafter referred to as Vmag (AC)) is applied. These DC voltage and AC voltage are applied from the developing bias power source to the developing roller 33 and the magnetic roller 32 via a bias control circuit (both not shown). The control unit 90 (see FIG. 6) transmits a control signal to the bias control circuit to control Vslv (DC), Vslv (AC), Vmag (DC), and Vmag (AC) applied from the developing bias power supply.

  As described above, the first stirring screw 31a and the second stirring screw 31b circulate in the developing container 30 while the developer is being stirred to charge the toner, and the first stirring screw 31a causes the developer to move to the magnetic roller 32. A magnetic brush (not shown) is formed on the magnetic roller 32 by being conveyed. The magnetic brush on the magnetic roller 32 is transported to a portion where the magnetic roller 32 and the developing roller 33 are opposed to each other after the layer thickness is regulated by the ear cutting blade 35. Then, a toner thin layer is formed on the developing roller 33 by a potential difference ΔV between Vmag (DC) applied to the magnetic roller 32 and Vslv (DC) applied to the developing roller 33 and a magnetic field.

  The first and second stirring screws 31a and 31b in the developing device 3 are connected to a developer stirring motor (not shown) via a gear train, and the first and second stirring screws 31a and 31b are connected to the first and second stirring screws 31a and 31b based on a control signal from the control unit 90. The second stirring screws 31a and 31b are driven. In addition, by connecting the developer stirring motor to the magnetic roller 32 and the developing roller 33 through a gear train, the driving source of the magnetic roller 32 and the developing roller 33 can also be used.

  The toner layer thickness on the developing roller 33 varies depending on the resistance of the developer and the difference in rotational speed between the magnetic roller 32 and the developing roller 33, but can be controlled by ΔV. When ΔV is increased, the toner layer on the developing roller 33 is thickened, and when ΔV is decreased, the toner layer is thinned. The range of ΔV at the time of development is generally about 100V to 350V.

  FIG. 4 is a diagram illustrating an example of a bias waveform applied to the developing roller 33 and the magnetic roller 32. As shown in FIG. 4A, a composite waveform Vslv (solid line) in which a rectangular wave Vslv (AC) having a peak-to-peak value of Vpp1 is superimposed on Vslv (DC) is applied to the developing roller 33. The magnetic roller 32 is applied with a composite waveform Vmag (broken line) in which Vmag (DC) has a peak-to-peak value of Vpp2 and Vmag (AC) of a rectangular wave having a phase different from Vslv (AC). The

  Therefore, the voltage applied between the magnetic roller 32 and the developing roller 33 is a composite waveform Vmag−Vslv having Vpp (max) and Vpp (min) as shown in FIG. Note that Vmag (AC) is set so that the duty ratio is larger than Vslv (AC). Actually, an AC voltage having a partially distorted shape is applied instead of a complete rectangular wave as shown in FIG.

  The toner thin layer formed on the developing roller 33 by the magnetic brush is conveyed to the opposite portion between the photosensitive drum 1 and the developing roller 33 by the rotation of the developing roller 33. Since Vslv (DC) and Vslv (AC) are applied to the developing roller 33, the toner flies from the developing roller 33 to the photosensitive drum 1 due to a potential difference with the photosensitive drum 1, and the static on the photosensitive drum 1. The electrostatic latent image is developed.

  Remaining toner that is not used for development is conveyed again to the opposing portion of the developing roller 33 and the magnetic roller 32 by the rotation of the developing roller 33 and is collected by the magnetic brush on the magnetic roller 32. Then, the magnetic brush is peeled off from the magnetic roller 32 by the same-polar part (peeling pole 48, pumping pole 49) of the fixed magnet body 32b, and then circulated between the first and second stirring chambers 30b, 30c. Returned to the drug. Then, a magnetic brush is formed on the magnetic roller 32 again as a two-component developer uniformly charged with an appropriate toner concentration, and conveyed to the earbrush blade 35.

  FIG. 5 is a side sectional view schematically showing the toner container 6. The toner container 6 includes a container container 61 that stores unused toner, a conveying screw 62, a stirring paddle 63, a toner replenishing motor 27, and a stirring motor 28.

  A supply port 61a connected to the toner supply port 30d (see FIG. 2) of the developing container 30 is formed at one end portion in the longitudinal direction (direction perpendicular to the paper surface of FIG. 5) of the bottom of the container container 61. The agitation paddle 63 has a film-like agitation blade 63a that extends from the shaft part to one side in the radial direction and is developed in the longitudinal direction of the container. The toner in the container container 61 is stirred by the rotation of the stirring blade 63a, and the stirred toner is transferred to the conveying screw 62 side.

  The transport screw 62 has a spiral blade 62a formed in a spiral shape with a constant phase (pitch) in the longitudinal direction around its shaft portion, and is disposed at the bottom of the container container 61 so as to face the supply port 61a. ing. When the transport screw 62 rotates, the toner stirred by the stirring paddle 63 is transported toward the supply port 61a by the advance of the phase of the spiral blade 62a, and is supplied to the developing container 30 through the supply port 61a.

  The toner replenishment motor 27 and the agitation motor 28 are DC motors that rotate the conveying screw 62 and the agitation paddle 63, respectively. For example, the toner supply motor 27 and the agitation motor 28 are driven to rotate by applying a pulse voltage to the bridge circuit and repeatedly turning the pulse voltage on and off. It is done. The stirring blade 63a of the stirring paddle 63 extends from the shaft portion to the outer edge of the conveying screw 62 in the radial direction, and can contact the spiral blade 62a.

  When the toner is sufficiently stored in the container 61, the stirring paddle 63 stirs the toner and supplies it to the conveying screw 62. When the toner replenishing motor 27 is driven to rotate at a constant speed, the conveying screw 62 replenishes a constant amount of toner corresponding to the rotational speed into the developing container 30 from the supply port 61a. Thereby, the toner concentration of the developer in the developing container 30 is kept constant. If the toner concentration in the developer in the developer container 30 detected by the toner concentration sensor 41 does not increase despite the toner being supplied, the control unit 90 indicates that the toner in the toner container 6 is empty. When it is determined that the toner container 6 is present, the user interface unit 54 (see FIG. 6) displays that the amount of toner remaining in the toner container 6 is empty (hereinafter referred to as toner end), and prompts the user to replace the toner container 6.

  The toner replenishment speed of the toner container 6 is constant when the remaining amount of toner in the toner container 6 is sufficient, but the replenishment speed decreases when the remaining amount of toner in the toner container 6 decreases. Therefore, when the toner supply amount (toner supply speed) per unit time from the toner container 6 decreases to a predetermined amount, a near end is displayed, and when the toner supply amount further decreases, a toner end is displayed. The near end may be detected based on the toner concentration in the developer in the developing container 30 detected by the toner concentration sensor 41 as in the case of the toner end. As will be described later, the image signal of the image to be printed is detected. It is also possible to predict using the printing rate calculated from

  Next, the control path of the image forming apparatus of the present invention will be described. FIG. 6 is a block diagram showing an example of a control path used in the image forming apparatus of the present invention. It should be noted that since various control of each part of the apparatus is performed when the image forming apparatus 100 is used, the control path of the entire image forming apparatus 100 becomes complicated. Therefore, here, a portion of the control path that is necessary for the implementation of the present invention will be mainly described. The image forming apparatus 100 includes an image input unit 50, an image processing unit 51, an image output unit 53, a user interface unit 54, a date and time information storage unit 55, a toner remaining amount detection unit 56, and an average toner consumption calculation. A unit 57 and a control unit 90 are provided.

  The image input unit 50 acquires image data about an output image. For example, when the image forming apparatus 100 is a digital multi-function peripheral as shown in FIG. 1, an image for optically reading an image drawn on a document. When the image forming apparatus 100 is a printer, the reading unit 20 is a receiving unit that receives image data transmitted from a personal computer or the like. The image signal input from the image input unit 50 is converted into a digital signal and then sent to the image processing unit 51. Note that the image input method described in the present embodiment is not merely intended to limit the scope of the present invention, but is merely an illustrative example.

  The image processing unit 51 includes an image attribute determination unit 511 and an output image creation unit 512. The image attribute determination unit 511 performs attribute determination such as “character attribute” and “image attribute” for each pixel of the image data transmitted from the image input unit 50. The output image creation unit 512 performs filter processing, color correction processing, halftone correction processing, and the like according to each image attribute whose attribute is determined by the image attribute determination unit 511.

  The user interface unit 54 indicates the state of the image forming apparatus 100, performs various settings of the image forming apparatus 100, and executes various functions such as image formation. Specifically, it displays image formation status, number of copies, remaining toner information such as “near end” and “toner end”, and functions such as double-sided printing and black-and-white reversal, magnification setting, density setting, and container replacement The date and time can be entered.

  The date / time information storage unit 55 stores time information such as container replacement date / time information input from the user interface unit 54. The toner remaining amount detection unit 56 includes a toner density sensor 41 and the like, and detects whether or not the toner remaining amount in the toner container 6 exceeds a predetermined threshold value. Specifically, if the output value of the toner density sensor 41 does not decrease after toner replenishment, it is determined that the toner container 6 is empty or nearly empty, and a near-end or toner-end display is displayed on the user interface unit 54. .

  The average toner consumption calculation unit 57 calculates the average toner consumption per image and the average toner per day based on the cumulative number of printed sheets and the cumulative toner consumption after the image forming apparatus 100 is shipped (initial use). Calculate consumption. For example, the toner consumption is measured by directly measuring the image density of a toner image formed on the surface of the photosensitive drum 1 using a reflection type density sensor or the like, or a toner image transferred onto a sheet. The toner consumption amount bn per image is calculated using the ratio of the image area to the image formable region. Further, an integrated toner consumption amount Σbn obtained by integrating the toner consumption amount bn per image is calculated, and the integrated toner consumption amount Σbn is divided by the cumulative number of operating days of the image forming apparatus 100 to obtain the average toner consumption amount per day. calculate.

  The average toner consumption can also be obtained from the average printing rate. The average toner consumption calculation unit 57 calculates a printing rate cn for each image based on the image signal input from the image input unit 50, and further calculates an integrated printing rate Σcn obtained by integrating the printing rate cn. Then, the average print rate C1 (%) per day is calculated by dividing the cumulative print rate Σcn by the cumulative number of working days of the image forming apparatus 100. The average toner consumption per day is calculated using the average printing rate C1 per day and the correlation between the printing rate and the toner consumption. Alternatively, the average print rate C2 (%) per image is calculated by dividing the integrated print rate Σcn by the total print number N2, and the average print rate C2 per image, the print rate, and the toner consumption amount are calculated. The average toner consumption per image is calculated using the above correlation.

  The control unit 90 is a central processing unit (CPU) as a central processing unit, and includes an image input unit 50, an image processing unit 51, an image output unit 53, a user interface unit 54, a date / time information storage unit 55, and a toner remaining amount detection. A control signal is transmitted to each unit and apparatus in the image forming apparatus 100 such as the unit 56 and the average toner consumption calculation unit 57. In addition, a signal indicating the state and an input signal are transmitted from each part and device.

  Further, the control unit 90 can execute a toner save mode in which the toner consumption is suppressed as much as possible and the quality of the printed image is maintained at a predetermined level from the near-end display to the toner-end display.

  Various specific methods for the toner save mode have been proposed in the past, and in the present invention, it is possible to perform toner save using such a conventional method. First, a toner saving method for changing the gamma correction table used when the output image creation unit 512 corrects the halftone gamma characteristic will be described.

  FIG. 7 shows an example of a gamma correction table, and FIG. 7A shows a gamma correction table used during normal printing. On the other hand, FIG. 7B is a gamma correction table used in the toner save mode according to the present embodiment. When both are compared, in the toner save mode, the correction output value is generally suppressed to reduce the brightness and The table prints with reduced saturation. In particular, for photographs (dashed lines) and graphics (dashed lines), the correction output value at higher densities is higher than that of text (solid line) (specifically, the correction output value during normal printing) By reducing the toner consumption from T0 to T1, the overall toner consumption is reduced.

  Next, a toner saving method using a lookup table will be described. In a color image forming apparatus such as a color printer or a color copying machine, a lookup table (gradation-density lookup) that associates and stores the gradation input value (exposure amount setting value) of each color and the output density target value corresponding thereto. The toner save mode can be executed by reducing the output density at a constant rate using a table.

  For example, when the gradation input values of cyan, magenta, and yellow are 50%, 60%, and 40%, respectively, the output density is reduced to 40%, 48%, and 32%, respectively. Output in concentration. When toner of a color image is saved by this method, the saturation of the image is slightly lowered, but the color tone of the image is maintained because the ratio of the output density of each color is the same as the input value.

  Based on the toner remaining amount calculated by the toner remaining amount detecting unit 56, the control unit 90 executes the toner save mode when the toner remaining amount becomes equal to or less than a predetermined value set in advance. Further, when executing the toner save mode, the control unit 90 displays a message for prompting the user interface unit 54 to shift to the toner save mode. Specifically, a message indicating that the replacement time of the toner container 6 is approaching (near end) (for example, a message such as “Soon to be out of toner”) is displayed.

  FIG. 8 is a flowchart showing a control example of the toner save mode executed in the image forming apparatus of the present invention. The execution procedure of the toner save mode will be described along the steps of FIG. 8 with reference to FIGS. As shown in FIG. 8, it is determined whether or not the toner remaining amount calculated by the toner remaining amount detecting unit 56 exceeds a preset value A (step S <b> 1), and the toner remaining amount is less than A. Is determined to be “near end”.

  At this time, a message notifying the user of the “near end” state is displayed on the user interface unit 54 (step S2), and a message requesting the user to determine whether or not to shift to the “toner save mode” is also displayed. (Step S3). When transition to “toner save mode” is selected, a message is displayed asking the user to determine whether to set “toner container replacement date” (step S4), and replacement date setting is selected Inputs the exchange date and time via the user interface unit 54 (step S5). The input exchange date and time is stored in the date and time information storage unit 55.

  The user interface unit 54 also displays a replacement date range that can be set based on the remaining amount of toner in the toner container 6, and determines whether the replacement date input in step S5 is within the specified range. (Step S6). If a date and time within the specified range has been input, a message prompting the user to determine whether or not to change the processing content for each image attribute is displayed (step S7), and the processing content for each attribute is displayed. Is to be changed, the “character priority mode” or the “image priority mode” is selected (step S8).

  For example, when “character priority mode” is selected, if the image input from the image input unit 50 is a character image, the toner save amount is reduced as much as possible to improve the output image quality, and the input image is an image image. In this case, the toner save amount is increased to a level that does not impair the gradation of the image, thereby suppressing toner consumption. On the other hand, when “image priority mode” is selected, if the input image is an image, the toner save amount is reduced as much as possible to improve the output image quality, and if the input image is a character image, the character image Toner consumption is suppressed by increasing the toner save amount to such an extent that the visibility of the image is not impaired.

  Then, based on the “average toner consumption per day” information calculated by the average toner consumption calculation unit 57, the degree of suppression of the toner consumption according to the “continuous use time” until the replacement date and time set by the user is set. Calculate (step S9). When the degree of suppression of the toner consumption is determined, the “toner save mode” is turned on (step S10), and the next printing is executed with the normal print mode changed to the “toner save mode” (step S10). Step S11).

  Thereafter, it is determined whether or not printing is completed (step S12). If printing is continued, it is determined whether or not the “toner save mode” flag is set (on state) (step S12). Step S13). When it is determined that the “toner save mode” is already on, the change in the remaining amount of toner in the toner container 6 and the continuous use period until the replacement date and time of the input toner container 6 are displayed for each job end. The degree of suppression of the toner consumption is recalculated based on the obtained “toner remaining amount” and “continuous use time” (step S14). On the other hand, when the toner save mode is in the off state (NO in step S13), the process returns to step S1, and thereafter the same processing is repeated (steps S1 to S12).

  If the date and time closer to the designated range displayed in step S5 is input as the replacement date (N1 in step S6), the image can be output up to the set replacement date and time without executing the toner save mode. Therefore, the next printing is executed without turning on the toner save mode (step S11). On the other hand, when the date and time before the displayed specified range is input as the exchange date and time (N2 in step S6), the image quality cannot be maintained until the exchange date and time. Please reset the date and time "to prompt the user to reset the replacement date and time.

  With the above processing operation, the user can accurately grasp the toner container replacement date and time without being stressed at the time of replacement of consumables. Further, since the toner save mode is executed from the near-end state of the toner container 6 set in consideration of usability and image quality in the design of the image forming apparatus 100, the image at the start or before the start of the toner save mode is executed. It is possible to prevent the occurrence of density reduction and density unevenness.

  In addition, by changing the processing content of the toner save mode (the degree of suppression of toner consumption) for each attribute of the input image, it is possible to save the toner with emphasis on the image quality of the character image or image image desired by the user. Become. Further, during execution of the toner save mode, an image with a high printing rate or a low printing rate is obtained by recalculating the degree of suppression of toner consumption using the remaining amount of toner and the period until the replacement date and time at the end of the job. Even if the images are continuously printed, the remaining amount of toner can be used up accurately in accordance with the input replacement date and time.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the dimensions, materials, shapes, relative arrangements, and the like of the components described in the above embodiment are not intended to limit the scope of the present invention only unless otherwise specified, and are merely illustrative examples. Only.

  In addition, the present invention is not limited to the monochrome multifunction device shown in FIG. 1, and various types of toner containers including a monochrome printer, a rotary or tandem color copying machine, a color printer, a facsimile, and the like that include toner containers for supplying toner to the developing device. Of course, it can be applied to an image forming apparatus.

  The present invention can be used for an image forming apparatus including a toner container for supplying toner to a developing device. By using the present invention, an image forming apparatus capable of accurately grasping the replacement time of the toner container while saving toner consumption within a range that does not impair image quality.

1 Photosensitive drum (image carrier)
2 Charging device 3 Developing device 4 Exposure device 5 Cleaning device 6 Toner container (toner container)
DESCRIPTION OF SYMBOLS 7 Fixing part 32 Magnetic roller 33 Developing roller 41 Toner density sensor 50 Image input part 51 Image processing part 511 Image attribute discrimination | determination part (image attribute discrimination | determination means)
512 Output image creation unit 53 Image output unit 54 User interface unit (display input means)
55 Date and time information storage unit 56 Toner remaining amount detecting unit (toner remaining amount detecting means)
57 Average toner consumption calculation unit (average toner consumption calculation means)
90 Control unit (control means)
100 Image forming apparatus

Claims (7)

An image input unit for inputting image information to be printed;
A developing device for forming a toner image corresponding to the electrostatic latent image on the surface of the image carrier;
A replaceable toner storage container for storing toner to be replenished to the developing device;
Toner remaining amount detecting means capable of detecting that the remaining amount of toner in the toner storage container has become a predetermined amount or less;
Average toner consumption calculating means for calculating an average toner consumption per image and an average toner consumption per day based on the cumulative number of printed sheets and the cumulative toner consumption immediately after the start of use of the image forming apparatus;
Control means capable of executing a toner save mode that suppresses toner consumption compared to normal printing when the remaining amount of toner in the toner container becomes equal to or less than a predetermined amount;
In an image forming apparatus comprising:
A message indicating that the remaining amount of toner in the toner storage container has become a predetermined amount or less is displayed, and whether or not the toner save mode needs to be executed and the replacement date and time of the toner storage container when the toner save mode is executed are displayed. It has a display input means that can be input,
The control means is based on the toner storage container replacement date and time information input by the display input means and the average toner consumption per day calculated by the average toner consumption calculation means. An image forming apparatus that changes a degree of suppression of toner consumption in a mode.   An image attribute determining unit configured to determine an attribute of the image information input from the image input unit; and the control unit determines a toner consumption amount in the toner save mode according to the image attribute determined by the image attribute determining unit. The image forming apparatus according to claim 1, wherein a degree of suppression is changed.   When the image information input from the image input unit is a character image, the display input unit includes a character priority mode for reducing a degree of toner consumption suppression compared to an image image, and an image input from the image input unit. The image forming apparatus according to claim 2, wherein when the information is an image image, an image priority mode for lowering a degree of suppression of toner consumption compared to a character image can be selectively input.   4. The image forming apparatus according to claim 1, wherein the display input unit displays a range of replacement date and time of the toner container that can be input when the toner save mode is executed. apparatus.   5. The image forming apparatus according to claim 4, wherein the control unit stops execution of the toner save mode when a date and time closer to the replacement date and time range displayed on the display and input unit is input. .   The said control means performs the display which prompts re-input of the replacement date when the date before the range of the replacement date displayed on the said display input means is input. The image forming apparatus described in 1.   The control means is based on a change in the remaining amount of toner in the toner container due to a printing operation after executing the toner save mode, and a change in a period until the input date and time of replacement of the toner container. The image forming apparatus according to claim 1, wherein the degree of suppression of toner consumption in the toner save mode is recalculated.

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