JP4590933B2 - Image forming apparatus and collection box - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile, or a complex machine using an electrophotographic method, and a collection box for collecting unnecessary toner.

  Conventionally, in an image forming apparatus such as a copying machine, a printer, a facsimile, or a composite machine to which this type of electrophotographic method is applied, the photosensitive drum as an image bearing member is centered and the circumferential surface of the photosensitive drum is opposed. A charging unit, an optical scanning unit, a developing unit, a transfer unit, and the like are arranged as described. In a full-color image forming apparatus, four developing units are provided for each color of CMYK as a developing unit, and a two-component developer composed of toner and a carrier is used.

  By stirring the toner and the carrier, the toner is charged (for example, minus polarity), and the electrostatic latent image on the photosensitive drum can be developed.

  By the way, in the developing device, when images with low image density are continuously processed, the developer is deteriorated by excessive stirring, and uneven density and fogging are likely to occur. As a means for preventing this, the toner is discharged onto the photosensitive drum (for example, a toner is formed by forming a belt-shaped electrostatic latent image), and the toner image is collected using a cleaning member. The developer in the developing device is replaced (see Patent Document 1 and Patent Document 2).

  The toner is collected by applying a voltage having a polarity opposite to that of the toner to a cleaning member (cleaning roll) provided corresponding to the photosensitive drum or the intermediate transfer member, and taking in the toner with an electrostatic force, and using a blade or the like. There is a mechanical scraping configuration.

  Incidentally, the toner collected by the cleaning member is conveyed to a collection box and stored.

  The collection box is provided with a near-full detection unit that detects immediately before the collected toner becomes full (near state).

  As an example of the near-full detection unit, a transparent storage unit that is provided on the recovery box side and stores a part of the recovery toner when the recovery toner is in a near-full state, and a transparent storage unit that is provided on the apparatus main body side. And a near sensor for detecting the transmission state.

  The collection box is provided with a storage space surrounded by a transparent member in which a predetermined amount of toner is stored in the collection box, and the photoelectric member is positioned so that the transparent member blocks the optical axis. A sensor (a near sensor) is provided. Therefore, when there is no toner in the space surrounded by the transparent member, the light emitted from the light projecting unit reaches the light receiving unit, and when the toner is filled in the space surrounded by the transparent member, The emitted light is blocked by the toner and does not reach the light receiving portion.

  By setting the amount of toner in the collection box when the transparent member is filled with toner in advance, it is possible to detect the near state.

  Here, conventionally, in the image forming apparatus, after detecting the near state with the near sensor in the recovery box, the replacement of the recovery box is informed to give the user a replacement period.

That is, after the near detection, the number of pixels based on the image data to be subjected to image formation processing is counted. For example, when converted to A4 size of JIS standard, the image density processing for 1000 sheets is performed at an image density of 5% for each color. It can be carried out. When the number reaches 1000, the apparatus is stopped because the collection box is full.
JP 2003-295559 A JP-A-11-295976

However, there are cases where excessive toner (toner recovered without being transferred to the storage medium) discharged during non-image formation is also recovered in the recovery box. Since the transparent member does not consider such recovery of discharged toner, there is a possibility that the near detection timing will be wrong.

  Even if the near detection is properly performed, the full tank determination based on the number of pixels based on the image data may not stop even if the allowable recovery amount of the recovery box is exceeded. The load on the toner transport mechanism and the like from the cleaning member to the collection box increases.

  In consideration of the above facts, the present invention can reliably determine the state immediately before the full tank according to the actual toner collection amount and the full tank state, and prevent the toner collection system from being overloaded by the excessive toner. An object of the present invention is to obtain an image forming apparatus and a collection box that can perform image processing.

According to a first aspect of the invention, there is provided charging means for uniformly charging the surface of the image carrier by applying a predetermined voltage to a charging member adjacent to the surface of the image carrier. electrostatic latent image forming means and the electrostatic latent image at least toner including current image agent for forming an electrostatic latent image by irradiating a light beam according to image data to the charged image carrier so as Developing means for developing the toner image, transfer means for transferring the toner image on the image carrier developed by the developing means to the recording medium directly or via the intermediate transfer body, and the recording medium transferred by the transfer means An image forming apparatus comprising: a fixing unit that fixes the upper toner image; and a density adjusting unit that adjusts a developing density by the developing unit by supplying or discharging a toner amount stored in the developing unit. And transfer the toner image on the image carrier. A transfer residual toner generated when the toner is discharged, or an unnecessary toner including a discharge toner generated when discharged by the density adjusting means, and a cleaning means for cleaning the surface of the image carrier, and an unnecessary toner taken by the cleaning means. A recovery box for recovering the waste toner, a near sensor for detecting a near state in which the amount of unnecessary toner recovered in the recovery box is a predetermined amount less than an allowable amount of unnecessary toner stored in the recovery box, and an unnecessary toner in the recovery box by the near sensor. first calculating means, after the detection of the Niyafuru state of waste toner in the recovered box by the Niyafurusensa, the concentration operation after detecting the Niyafuru state, the actual processing amount based on the image data of the The pseudo processing amount by converting the toner discharge amount by the adjusting means Second calculating means for calculating, when said sum of the actual processing amount and the pseudo processing amount reaches the reference value, a full determination means for determining said collection box becomes full state, the Have.

  According to the first aspect of the present invention, when the near state is detected by the near sensor, the full tank determining means is activated.

That is, the first calculation means calculates the actual processing amount based on the image data, and the second calculation means converts the toner discharge amount by the density adjustment means into a pseudo processing amount, and both add up. The full determination means determines whether or not the sum reaches a predetermined reference value, if the sum has reached the reference value, the collection box is determined to become full state.

  After the full tank determination, for example, by taking a measure such as forcibly stopping the apparatus, it is possible to prevent the toner constituting the cleaning unit from being overloaded with the toner that cannot enter the collection box. .

  In the first invention, the actual processing amount and the pseudo processing amount are converted into the number of pixels which is a minimum unit of an image.

  By converting to the number of pixels, for example, it is possible to obtain data in which the image density is added to the number of processed images.

According to a second aspect of the invention, there is provided charging means for uniformly charging the surface of the image carrier by applying a predetermined voltage to a charging member adjacent to the surface of the image carrier. electrostatic latent image forming means and the electrostatic latent image at least toner including current image agent for forming an electrostatic latent image by irradiating a light beam according to image data to the charged image carrier so as Developing means for developing the toner image, transfer means for transferring the toner image on the image carrier developed by the developing means to the recording medium directly or via the intermediate transfer body, and the recording medium transferred by the transfer means And a fixing unit for fixing and collecting unnecessary toner on the image carrier, wherein the recovery box has a relative recovery volume. A small first region and a relatively large second The region is partitioned by a partition wall, and is stored in the first region when the collected toner amount is in a near-full state that is a predetermined amount less than the toner storage allowable amount of the entire recovery box. A concave portion is formed by a partition for determining the state of the full condition so that a part of the toner is accommodated, and the apparatus main body side indicates whether or not the toner is accommodated in the concave portion when the collection box is loaded. When the toner stored in the first region becomes a state of being near to the volume of the first region, toner is detected in the recessed portion. as will be accommodated, the opening is formed from the second region toner flows into the first region, the lower end portion of the opening than the upper end of the Niyafuru state discrimination partition wall There, it is characterized in that.

  According to the second invention, the structure of the recovery box is partitioned by the partition wall into a region having a relatively large recovery volume and a region having a relatively small recovery volume.

  The concave portion for detecting the near state is provided in the first region having a relatively small recovery volume, and improves the responsiveness until the recovered toner is accumulated and becomes a near state. That is, since the amount of change of the so-called “bulk” (for example, change in the height of deposition) is larger when the overall capacity is smaller, it is possible to accurately determine the near state.

  On the other hand, toner other than the first area is stored in the second area. However, when a large amount of toner that causes the balance between the second area and the first area to be lost is sent, There are cases in which the time for determining the near state in the region is missed.

  Therefore, when the toner stored in the first region becomes a near-full state with respect to the volume of the first region, the second region has the second region so that the toner is accommodated in the recessed portion. An opening through which toner flows into the region 1 was provided.

  When an extremely large amount of toner is fed into the second region through the opening, a part of the toner flows into the first region through the opening, and the deposition change between the first region and the second region occurs. The balance of quantity can be maintained, and accurate detection of the near state can be maintained.

  As described above, according to the present invention, it is possible to reliably determine the state immediately before the collection box is full and the full state in accordance with the actual toner collection amount, and to prevent the toner collection system from being loaded with excess toner. It has an excellent effect of being able to.

(overall structure)
FIG. 1 shows an outline of an image forming apparatus 10 according to an embodiment of the present invention. The image forming apparatus 10 includes an engine unit 12, and a paper feeding unit 14 is provided below the engine unit 12.

  The paper feed unit 14 includes a paper tray 22 on which paper is stacked and a paper feed roll 24 that sends out the paper from the paper tray 22, and the paper delivered by the paper feed roll 24 is transported by a transport roll. The paper passes through the paper feed path 30 through the paper 26 and 28, and is conveyed to a transfer roll 74 described later.

  After the toner image is transferred onto the paper by the transfer roll 74 and fixed by the fixing roll 32A of the fixing unit 32, it is provided on the upper portion of the engine unit 12 by the discharge roll 36 or the discharge roll 38 depending on the position of the switching claw 34. The discharged first discharge tray 16 or the second discharge tray 18 is discharged.

  Here, in the case of double-sided printing, after the printing of the front surface is completed in the order as described above, before the paper is completely discharged to the first discharge tray 16, the discharge roll 36 is reversed and the paper is reversed. Supplied to the line 40. The paper is then returned to the paper feed path 30 through the transport rolls 42, 44, 46, and 48, and the back side of the paper is printed. In the case of manual printing, by placing paper on the manual feed tray 20, the paper is transported from the manual feed roll 49 to the paper feed path 30 via the transport roll 48 and printed.

  Meanwhile, on the right side of FIG. 1 of the image forming apparatus 10, four developer cartridges 64 filled with a developer for each color (made of toner and magnetic carrier) are arranged. Each developer cartridge 64 is connected to a later-described developer unit 58 (developer 60Y, 60M, 60K, 60C) arranged in order from the top of FIG. The developer in 64 is supplied to the developing devices 60Y, 60M, 60K, and 60C.

  An exposure unit 62 is arranged on the left side of the developer cartridge 64 in FIG. 1, and four laser beams L (Y), L (M), and L (K) corresponding to the image signal are provided from the exposure unit 62. , L (C) is emitted toward the photoconductor 52 constituting the photoconductor unit 50 arranged on the left side of the exposure unit 62 in FIG. 1 to form a latent image on the photoconductor 52.

  The photoconductor unit 50 includes four photoconductor drums 52 (52Y, 52M, 52K, and 52C) arranged in the vertical direction. For example, yellow (52Y), magenta (52M), black (52K), and the like from the top. For cyan (52C).

  The exposure unit 62 outputs laser light L (Y), L (M), L (K), and L (C) (hereinafter collectively referred to as laser light L) of each color Y, M, C, and K. The light source unit, a modulation processing unit that modulates and scans the laser light L, an fθ lens that corrects the scanning speed on the exposure surface, a surface tilt correction cylindrical lens that has lens power in the scanning direction, and the like. And an optical system.

  In the exposure unit 62, the laser light L of each color emitted from the light source unit enters the modulation processing unit, is modulated according to the image information for each color, and is scanned by the polygon mirror 67 rotated by the polygon motor 63. (Main scanning). The laser light L of each color scanned by the polygon mirror 67 is reflected by the mirror group 69 in the arrangement direction of the photoconductor 52 corresponding to each color and is imaged on each photoconductor 52.

  The photoconductor unit 50 includes a charging roll 56 and a refresh roll 54 corresponding to each photoconductor 52, and is provided so as to rotate in contact with the photoconductor 52. In the charging roll 56, the photosensitive member 52 is uniformly charged, and toner flying from a magnet roll 80 provided in the developing unit 58 described later is attached to the surface of the photosensitive member 52. On the other hand, the refresh roll 54 discharges the photoconductor 52 to remove unnecessary toner adhering to the surface of the photoconductor 52, thereby preventing ghosts and the like caused by the toner remaining on the surface of the photoconductor 52.

  Here, the developing unit 58 is arranged on the lower right side in FIG. 1 of each photosensitive unit 50, and four developing units 60 corresponding to the respective photosensitive drums 52 (52Y, 52M, 52K, 52C). (60Y, 60M, 60K, 60C) are arranged in the vertical direction.

  The developing device 60 is in a trickle developing system (in order to prevent the charging performance of the developer from being lowered and to extend the interval for changing the developer, the developer is gradually replenished in the developing device, but becomes excessive ( This is a developing system in which development is performed while discharging a deteriorated developer (which contains a lot of deteriorated carriers), and the deteriorated developer is collected in a collection container (not shown).

  On the other hand, an intermediate transfer unit 66 is arranged on the left side of the photoconductor unit 50 in FIG. 1, and three drum-shaped intermediate transfer bodies 68, 70, and 72 are provided. The two primary intermediate transfer members 68 and 70 are arranged vertically in the vertical direction, and the upper primary intermediate transfer member 68 rotates in contact with the two photoconductors 52Y and 52M disposed on the upper portion of the photoconductor 52. The lower primary intermediate transfer member 70 rotates in contact with the two photosensitive members 52K and 52C disposed at the lower portion. Further, the secondary intermediate transfer body 72 is rotated in contact with both the primary intermediate transfer bodies 68 and 70, and the transfer roll 74 described above is rotated in contact with the secondary intermediate transfer body 72.

  Accordingly, the toner images are transferred from the photosensitive members 52Y and 52M to the primary intermediate transfer member 68, and the toner images are transferred from the photosensitive members 52K and 52C to the primary intermediate transfer member 70, respectively. The two-color toner images transferred to the primary intermediate transfer bodies 68 and 70 are transferred to the secondary intermediate transfer body 72 to form four colors, and the four-color toner images are transferred onto the sheet by the transfer roll 74. It will be.

  A cleaning roll 76 and a cleaning brush 78 are disposed in the vicinity of these intermediate transfer bodies 68, 70, 72, respectively, and unnecessary toner on the surfaces of the intermediate transfer bodies 68, 70, 72 is scraped off.

  As shown in FIG. 3, the cleaning roll 76 and the cleaning brush 78 are attached to the casing 79 </ b> A of the cleaning unit 79. The cleaning unit 79 is disposed corresponding to the secondary intermediate transfer body 72, but the cleaning unit disposed corresponding to the primary intermediate transfer bodies 68 and 70 has the same structure.

  Here, the unnecessary toner collected by the cleaning brush 78 is discharged (statically) to the secondary intermediate transfer body 72 again and taken in by the cleaning roll 76.

  The cleaning roll 76 corresponds to a temporary storage part 79B in which an auger 79C in which a metal wire is spirally wound around a predetermined axis, and unnecessary toner taken in by the cleaning roll 76 is a blade. It is scraped off by 79D and stored in the temporary storage unit 79B.

  In the temporary storage unit 79B, the auger 79C rotates in the axial direction, thereby conveying unnecessary toner stored in the temporary storage unit 79B in the direction of one shaft end.

  One shaft end of the temporary storage unit 79B is opened and communicates with the recovery box 150 (see the chain line in FIG. 1).

  As shown in FIG. 4, the collection box 150 is provided with three through holes 152, 154 and 156.

  The three through holes 152, 154, and 156 collect unnecessary toner from temporary storage portions provided respectively corresponding to the two primary intermediate transfer bodies 68 and 70 and one secondary intermediate transfer body 72. Have a role.

  The collection box 150 is disposed on the front side of the page with respect to the engine unit 12 and is detachably attached by the user. The structure of the collection box 150 will be described later.

  As shown in FIG. 2, the developing device unit 58 includes four developing devices 60, and each developing device 60 includes a box-shaped housing 110 and a lid 120 that closes the housing 110. Includes a magnet roll 80 (developer carrier) for supplying toner to the photoconductor 52, a spiral auger 112 (supply member) and a spiral auger for stirring the developer in the developing device 60 and supplying the developer to the magnet roll 80. 114 (stirring member) is rotatably supported.

  Each developing device 60 can move between a position where the magnet roll 80 abuts on the photoconductor 52 and a position where the magnet roll 80 is retracted from the photoconductor 52, and the magnet roll 80 contacts the photoconductor 52 during image formation. It comes to touch. As a result, toner adheres to the photoconductor 52 corresponding to the latent image formed on the photoconductor 52. However, when image formation is not performed, the developing unit 58 is retracted from the photoconductor 52. It is supposed to be.

  A developing bias voltage in which a DC component is superimposed on an AC component is applied to the magnet roll 80, whereby toner is electrostatically attached only to the electrostatic latent image (image portion) of the photoconductor 52, thereby causing a toner image. Is formed.

(Structure of collection box 150)
As shown in FIGS. 4 and 5, the recovery box 150 has a thin box shape, and two through holes 152 and 154 are provided along the vertical direction at the center in the width direction toward FIG. . The upper through-hole 152 (hereinafter referred to as the first through-hole 152) corresponds to the temporary storage portion disposed in the YM primary intermediate transfer body 68, and the lower through-hole 154 (hereinafter referred to as the second through-hole 152). The through hole 154) corresponds to the temporary storage portion 79B disposed in the primary intermediate transfer body 70 for KC color.

  A partition wall 158 is provided between the two through holes 152 and 154. The partition wall 158 has an upper portion inclined upward to the right as viewed in FIG.

  The upper end of the partition wall 158 reaches the side position of the first through hole 152, and the lower end reaches the bottom plate portion 160 of the collection box 150.

  By this partition wall 158, the bottom plate portion 160 is partitioned, and the ratio of the left side and the right side in FIG. 4 is about 1: 2.

  Here, the unnecessary toner flowing from the first through hole 152 is guided along the upper surface of the partition wall 158 toward the bottom plate portion 160A on the left side in FIG. Further, the unnecessary toner flowing from the second through hole 154 is guided toward the right bottom plate portion 160B toward the right side of FIG. 4 divided by the partition wall 158.

  Further, in the collection box 150, in the vicinity of the upper left side wall in FIG. 4, a through hole 156 corresponding to the temporary storage portion 79B disposed in the secondary intermediate transfer body 72 (hereinafter referred to as a third through hole 156). ) Is provided.

  Immediately below the third through hole 156 is a bottom plate portion 160A on the left side as viewed in FIG. 4 partitioned by the partition wall 158, and at an intermediate position, the slope rises to the right as viewed in FIG. Convex part 162 having is formed. The upper end of the convex portion 162 reaches the left side of the first through hole 152, and the lower end is at a position where a predetermined gap is opened with respect to the side wall of the collection box 150.

  Therefore, the unnecessary toner flowing from the third through hole 156 passes along the upper surface of the convex portion 162 through the gap with the side wall of the recovery box 150 and is partitioned by the partition wall 158 toward FIG. It reaches the bottom plate 160A on the left side.

  Further, on the right side of the collection box 150 in FIG. 4, four through holes 164Y, 164M, 164K, and 164C with lids provided respectively corresponding to the developing units 58 of the respective colors are provided in the vertical direction. . A partition wall 166 is provided between each of the through holes with lids 164Y, 164M, 164K, 164C. The through holes 164 </ b> Y, 164 </ b> M, 164 </ b> K, and 164 </ b> C with a lid have a function of collecting the developer (particularly carrier) from the developing unit 58. Since the amount of collected carrier is smaller than that of unnecessary toner, the carrier is collected in each of the carrier collection areas 168Y, 168M, 168K, 168C divided by the partition 166, and is filled before the unnecessary toner. Never become.

  A part (right half of FIG. 4) of the bottom plate portion 160B on the right side in FIG. 4 partitioned by the partition wall 158 is used as the carrier recovery area 168Y, 168M, 168K, 168C (for C color). As a result, an area for collecting unnecessary toner flowing from the second through hole 154 (hereinafter referred to as the first area 170) flows from the first through hole 152 and the third through hole 156. The volume is smaller than a region for collecting unnecessary toner (hereinafter referred to as the second region 172).

  The volume ratio between the first area 170 and the second area 172 is proportional to the amount of unnecessary toner that flows in per unit time, and both the first area 170 and the second area 172 are almost simultaneously. It is configured to fill up.

Here, on the right side of the first region 170 in FIG. 4, a near state determining partition wall 174 is formed. The upper end of the near wall state partition wall 174 is bent so as to incline toward the left shoulder toward FIG. A dimension A is provided from the bottom plate portion 160B to the upper end of the partition wall 174 for determining the full state.

  Speaking of the relationship between the first region 170 and the second region 172 at the position of the partition wall 158, a partition wall 158 is provided at a position of dimension B from the left end toward the FIG. 4 of the bottom plate portion 160, A near state partition wall 174 is provided at a position of dimension C from the partition wall 158. The dimension B is larger than the dimension C.

  A small capacity accommodating member 176 is integrally formed on the bottom plate portion 160 on the right side of the partition wall 174 for determining the full state as viewed in FIG. 4 so as to protrude from the bottom plate portion 160. The housing member 176 is made of a transparent material and can visually recognize whether or not unnecessary toner is contained therein.

  In the present embodiment, when the collection box 150 is loaded in the apparatus main body, a photoelectric sensor 222 (an imaginary view in FIG. 4) configured with a light projecting unit and a light receiving unit so that the housing member 176 is sandwiched on the apparatus main body side. Line, see FIGS. 6 and 7). In the photoelectric sensor 222, when light is emitted from the light projecting portion, a housing member 176 is interposed on the optical axis.

  For this reason, when unnecessary toner is not present in the housing member 176, the light reaches the light receiving portion, and when unnecessary toner is present, the light is blocked by the unnecessary toner and does not reach the light receiving portion. That is, it is possible to determine the presence or absence of unnecessary toner in the storage unit 176 in the light receiving state by the light receiving unit. When it is determined that there is toner, it can be determined that this time is a near state indicating that the toner in the collection box 150 is almost full.

  In the collection box 150 configured as described above, in the present embodiment, an opening 178 that communicates the first region 170 and the second region 172 is provided in a part of the partition wall 158. The opening portion 178 is provided between the lower end of the inclined portion of the partition wall 158 and the bottom plate portion 160.

The lower end of the opening 178 is located at a dimension D from the bottom plate 160. This dimension D is higher than the height (dimension A) of the partition wall 174 for determining the full state .

Further, the upper end of the opening 178 is located on the extended line along the inclination of the inclined upper end of the above-mentioned partitioning wall 174 for determining the full state (see the chain line in FIG. 4).

  Further, the height dimension D of the partition wall 158 satisfies the following relationship.

A + {D × (B / C)} (1)
In addition, although it overlaps, the definition of each variable is enumerated.

A: Height dimension of partition wall for determining near-full state B: Dimension of bottom plate part 160A of second region 172 C: Dimension of bottom plate part 160B of first region 170 D: Height dimension of partition wall 158 The portion 178 is offset from the housing member 176 in the depth direction of FIG.

  By providing the opening 178 in the partition wall 158 under the above conditions, when a large amount of unnecessary toner accumulates in the second region 172, a part of the toner flows into the first region 170 from the opening 178, and the second region 172 In synchronism when the region 172 becomes a near state, the near state can be detected in the first region 170 (detection by the photoelectric sensor 222).

  The accumulation of a large amount of unnecessary toner can occur by TC concentration control of process control described later.

(Process control)
Here, in the full color printer according to the present embodiment, a process control operation is executed at a predetermined timing, and control is performed so that the density of each color toner image is equal to the predetermined density. This process control operation is performed, for example, when the printer is turned on, when a predetermined number of prints are performed, when the rotational speed of the photosensitive drum 2 reaches a predetermined value, or within the printer main body 1. It is executed at a predetermined timing such as when the temperature or humidity changes by a predetermined value or more.

  In the process control operation described above, patch marks made of toner images of yellow (Y), magenta (M), cyan (C), and black (K) are formed on the photosensitive drum 52 with predetermined values such as 100% and 50%. Density sensor (not shown) in a state where the toner patch marks of each color formed on the photosensitive drum 52 are transferred onto the primary intermediate transfer bodies 68 and 70 or the secondary transfer body 72. By adjusting the toner density (hereinafter referred to as TC density control) in the developing devices 60Y, 60M, 60C, and 60K, the exposure amount of the exposure unit 62 (hereinafter referred to as light quantity control), and the like. The control operation is performed so as to obtain

  In the TC density control, the density is adjusted by supplying toner to the developing unit 58 or discharging the stored toner. That is, particularly when toner is discharged from the developing unit 58, the discharged toner is not transferred to the sheet, but is collected in the collection box 150 via the cleaning roll 76 and the temporary storage unit.

(Image formation control system)
Next, a control system for image formation in the engine unit 12 will be described with reference to the control block diagram of FIG.

  The main power management unit 200 is connected to a commercial power source (not shown), generates a low voltage power source and a high voltage power source, and supplies power to each unit via a power supply line.

  A user interface 204 is connected to the main controller 202, and an instruction regarding image formation or the like is given by a user's operation, and information on the image formation or the like is notified to the user.

  The main controller 202 is connected to a network line with an external host computer (not shown) so that image data is input.

  When the image data is input, the main controller 202 analyzes, for example, the print instruction information included in the image data and the image data, and converts them into a format suitable for the engine unit 12 (for example, bitmap data). Image data is sent to the image formation processing control unit 206.

  The image formation processing control unit 206 controls each of the optical scanning system control unit 208, the drive system control unit 210, the charger control unit 212, the developing device control unit 214, and the fixing device control unit 216 based on the input image data. Synchronous control is performed to execute image formation.

  The main controller 202 is connected to a photoelectric sensor 222 provided in the collection box 150.

  In this embodiment, when the photoelectric sensor 222 detects a near-null state, the main controller 202 displays a message prompting the replacement of the collection box on the display surface of the user interface 204, or generates a warning sound. And a subsequent full state of the collection box 150 is determined by arithmetic processing based on the processing amount and the amount of toner discharged by TC concentration control.

  Hereinafter, the toner amount management control in the collection box 150 executed in the main controller 202 will be described with reference to the functional block diagram of FIG.

  The photoelectric sensor 222 is connected to the near state determination unit 250, and the result detected by the photoelectric sensor 222 is input to the near state determination unit 250.

  In the near state determination unit 250, when a signal (for example, a low level signal) output when the light receiving unit of the photoelectric sensor 222 receives light from the light projecting unit is detected, it is determined that the near state is not reached. On the other hand, when a signal (for example, a high level signal) output when the light receiving unit does not receive light from the light projecting unit is detected, it is determined that the state is a near state.

  The near state determination unit 250 is connected to the message output unit 252 and the full tank determination activation instruction unit 254. When the near state determination unit 250 determines that the state is a near state, it outputs a message output instruction signal to the message output unit 252. As a result, the message output unit 252 controls the user interface 204 to display a message prompting the replacement of the collection box 150 and output an alarm or the like.

  On the other hand, when it is determined that the near state is in the near state, the near state determination unit 250 outputs a start signal to the full state determination start instruction unit 254.

  When the full tank determination activation instructing unit 254 controls the image data capturing unit 256 by inputting the activation signal to capture image data, and controls the discharge amount reading unit 258 to perform TC concentration control. Read out the discharge amount.

Image data captured by the image data acquisition unit 256 is sent to the pixel P _G conversion unit 260, converts the toner usage based on the image data to the number of pixels P _G. Further, the amount of data discharged read in discharged amount reading unit 258 is sent to the pixel P _H conversion unit 262, converts the amount discharged to the number of pixels P _H.

The pixel PG conversion unit 260 and the pixel PH conversion unit 262 are respectively connected to the addition unit 264, and the converted pixel number P _G and pixel number P _H are added (P ← P _G + P _H ).

Number of pixels P which are added in the addition unit 264 is sent to the comparing unit 266, the comparison unit 266, and is compared with a reference value P _C read out from the reference value P _C storage unit 268. This reference value PC is a predetermined number of pixels, and in this embodiment, it corresponds to about 1000 sheets when a full car image is formed in the A4 size of the JIS standard.

  The comparison result in the comparison unit 266 is sent to the full tank state determination unit 270, where it is determined whether or not the reference number of pixels has been reached, that is, the tank is full. An instruction to forcibly stop the apparatus is issued via the forced stop instruction unit 272.

  The operation of this embodiment will be described below.

(Flow of image forming process)
Around each photosensitive member 52, an image forming (printing) process for each color by a known electrophotographic method is performed as follows.

  First, each photoreceptor 52 is rotationally driven at a predetermined rotational speed (for example, 95 mm / sec).

  As shown in FIG. 1, the surface of the photoconductor 52 is uniformly charged to a predetermined level by applying a DC voltage of a predetermined charging level (for example, about −800 V) to the charging roll 56. In the present embodiment, only a DC voltage is applied to the charging roll 56, but an AC component may be superimposed on the DC component.

  Next, the exposure unit 62 irradiates the surface of each photoconductor 52 having a uniform surface potential with laser light L corresponding to each color, and an electrostatic latent image corresponding to image information for each color is formed. . Thereby, the surface potential of the exposed portion of the photosensitive member 52 by the laser light L is neutralized to a predetermined level (for example, about −60 V or less).

  The electrostatic latent image formed on the surface of each photoconductor 52 is developed by each corresponding developing device unit 58 and visualized on each photoconductor 52 as a toner image of each color.

  Next, each color toner image formed on each photoconductor 52 is electrostatically primary-transferred onto the corresponding primary intermediate transfer drums 68 and 70. Here, the Y and M toner images formed on the photosensitive drums 52Y and 52M are on the primary intermediate transfer drum 68, and the K and C toner images formed on the photosensitive drums 52K and 52C are the primary intermediate. Each image is transferred onto the transfer drum 70.

  Thereafter, the toner image formed on the primary intermediate transfer drums 68 and 70 is electrostatically secondary-transferred onto the secondary intermediate transfer drum 72. As a result, on the secondary intermediate transfer drum 72, toner images from a single color image to a quadruple color image of each color of Y, M, K, and C are formed.

  Finally, the toner image formed on the secondary intermediate transfer drum 72 is tertiary-transferred onto the paper passing through the paper conveyance path by the transfer roll 74. After the tertiary transfer, the toner image formed on the paper is heat-fixed by the fixing unit 32, and the image forming process ends.

(Recovery box management (Nearful state discrimination))
Here, in the present embodiment, unnecessary toner on the primary transfer bodies 68 and 70 and the secondary transfer body 72 generated during the image forming process, or the toner is discharged from the developing unit 58 by TC density control, and is transferred to the primary transfer body. The toner remaining on the bodies 68 and 70 and the secondary transfer body 72 is taken in by the cleaning unit 79 and collected in the collection box 150.

  At the time of recovery to the recovery box 150, when a full tank is detected, if the user requests replacement, the image forming process cannot be performed until the replacement, so the state immediately before full (near full state) is detected. Then, after prompting the replacement, a predetermined amount of image forming processing is allowed.

  For this reason, since the detection of the near state has a great influence on the subsequent image formation processing amount, it is necessary to surely detect it. However, unnecessary toner other than the image formation processing (that is, unnecessary toner discharged by TC density control). ) Was not considered.

  Therefore, in the present embodiment, the structure of the collection box 150 is realized so as to reliably detect the near state even when unnecessary toner is discharged by the TC concentration control.

  Unnecessary toner due to image formation flows into the collection box 150 from the first to third through holes 152, 154, and 156, and unnecessary toner that has flowed from the first and third through holes 152 and 156 flows into the second region. The unnecessary toner that has reached 172 and has flowed from the second through hole 154 reaches the first region 170.

  On the other hand, unnecessary toner discharged by the TC concentration control flows into the collection box 150 from the third through hole 156. For this reason, the unnecessary toner accumulates on the bottom plate portion 160 </ b> A in the second region 172 through the gap between the convex portion 162 and the side wall of the collection box 150 along the upper surface of the convex portion 162.

  Here, the unnecessary toner generated by the image forming process increases in volume in an amount proportional to the volume difference between the first region 170 and the second region 172. When the region 170 passes through the near wall state partition wall 174 and is accommodated in the housing portion 176, the near state can be detected by the photoelectric sensor 222. At this time, the second region 172 is also almost in the near state. .

  However, when the toner is discharged, the balance of the accumulation amount of the first region 170 and the second region 172 is lost, and even if the second region 172 exceeds the near-full state and becomes full, the first region 170 becomes full. One region 170 may not be in a full state.

  Therefore, an opening 178 is provided in the partition wall 158 between the first region 170 and the second region 172, and a part of unnecessary toner that accumulates in the second region 172 is transferred to the first region 170. The balance between the first area 170 and the second area 172 is maintained.

  The opening 178 is provided under the following conditions.

(1) Height dimension D of partition wall 158> Height dimension of partition wall 174 for determining the full state (2) The upper end of the opening 178 is an extension in the inclined direction provided above the partition wall 174 for determining the full state Located in.

(3) The height dimension A of the partition wall for determining the near state, the dimension B of the bottom plate portion 160A of the second region 172, the dimension C of the bottom plate portion 160B of the first region 170, and the height dimension D of the partition wall 158 Relationship
A + {D × (B / C)} (1)
Meet.

  (4) The storage unit 176 is offset in the depth direction.

  By forming the opening 178 under the above conditions (1) to (4), it is possible to determine the precise state with high accuracy.

(Collection box management (full tank monitoring control))
On the other hand, even if the near state with high accuracy is determined, if the amount of unnecessary toner thereafter is not accurately determined, the allowable image forming processing amount does not match the actual full state of the collection box 150. Unnecessary toner may be collected excessively, resulting in a drive overload such as a drive system of the cleaning unit 79. Therefore, in the present embodiment, appropriate full tank detection control is performed in consideration of both image forming processing and toner discharge by TC density control.

  FIG. 8 illustrates a collection box management control routine controlled by the main controller 202.

In step 300, the number of pixels P _G and the number of pixels P _H are respectively initialized, and then the process proceeds to step 302 to determine whether or not the near state is detected by the photoelectric sensor 222.

  If an affirmative determination is made in step 302, the process proceeds to step 304 and the user interface 204 is controlled to output a message that prompts replacement of the collection box 150.

Next, at step 306, whether there is print instruction is determined, and if an affirmative decision is made, based on the image data of the print instruction in step 308, converts the used amount of toner to the number of pixels P _G, the routine proceeds to step 310 To do. If a negative determination is made in step 306, the process proceeds to step 310.

In step 310, whether there has been discharged the toner by TC concentration control is determined, the process proceeds to step 314 by converting the amount of toner discharged shifts If an affirmative decision is made to step 312 in number of pixels P _H. On the other hand, if a negative determination is made in step 310, the process proceeds to step 314.

In step 314, the pixel number P _G converted in step 308 and the pixel number P _H converted in step 312 are added (summed) (added value = P), and then the process proceeds to step 316 to determine a predetermined reference value. It reads the P _C, the routine proceeds to step 318.

In step 318, the read reference value P _C is compared with the addition value P, and when it is determined that P _C <P, it is determined that the amount of toner collected in the collection box 150 exceeds the allowable amount, The process proceeds to step 320 to execute (or instruct to execute) the forced stop process of the apparatus.

If it is determined in step 318 that P _C ≧ P, it is determined that the toner amount in the collection box 150 does not exceed the allowable amount, and the process proceeds to step 322.

  In step 322, it is determined whether or not the collection box 150 has been replaced. If the determination is negative, the process returns to step 306 to repeat the above process.

  If the determination in step 322 is affirmative, since the collection box 150 is a new collection box, the collection box monitoring ends.

  FIGS. 9 and 10 show changes in the amount of toner collected in the collection box 150 after the near state determination. FIG. 9 shows that after the near state determination, all image processing is only K color processing (monochrome image processing). ). When such black-and-white image processing is executed, the other colors (CMY) are excessively agitated in the developer unit 58 (the agitation drive source is common) due to the structure of the engine unit 12 of the present embodiment, and charged. Since the amount deviates from the appropriate value (TC decrease), discharge is performed.

  By converting this discharge amount into pixels and adding it to the pixel conversion value of the toner recovery amount resulting from the black and white image forming process, the toner amount in the recovery box 150 becomes full with a preset number of pixels.

  FIG. 10 shows a case where a full-color image and a black and white image are processed after the near state is detected. If the toner discharge is not considered after the black and white image forming process is performed, as indicated by a chain line in FIG. In addition, even if the toner collection allowable amount of the collection box 150 is exceeded, the reference number of pixels is not reached. Therefore, as shown by the solid line (thick line) in FIG. 10, the toner discharge amount is converted into pixels and added, so that the full of the collection box 150 can be detected at an appropriate time.

  The toner discharge is performed after the black and white image is formed, but may be performed before the black and white image is formed.

1 is a side view showing an image forming apparatus according to the present embodiment. It is an enlarged view of the developing unit according to the present embodiment. It is an enlarged view of a cleaning unit. It is a front view which shows the internal structure of a collection box. It is a perspective view which shows the internal structure of a collection | recovery box. It is a control block diagram of an engine part. It is a control function block diagram for full tank detection in the main controller. It is a flowchart which shows the control routine for monitoring a collection box. FIG. 6 is a characteristic diagram (monochrome image formation) showing a transition of the number of pixels in which the toner amount is converted based on the relationship between the actual processing number and the number of pixels. FIG. 6 is a characteristic diagram (monochrome image / full color image formation mixed) showing a transition of the number of pixels in which the toner amount is converted based on the relationship between the number of processed images and the number of pixels.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 12 Engine part 32 Fixing part 50 Photoconductor unit 52 Photosensitive drum (Image carrier)
60 Developing Unit 62 Exposure Unit 64 Developer Cartridge 68, 70, 72 Intermediate Transfer Member 79 Cleaning Unit (Cleaning Unit)
150 Recovery Box 152 First Through Hole 154 Second Through Hole 158 Partition Wall 160A, 160B Bottom Plate Part 156 Third Through Hole 162 Convex Part 164Y, 164M, 164K, 164C Through Hole with Cover 166 Partition 168Y, 168M, 168K 168C Carrier recovery area 170 1st area 172 2nd area 174 Partition for full state determination 178 Opening 200 Main power management section 202 Main controller 204 User interface (abnormality avoiding means)
206 Image formation processing control unit 208 Optical scanning system control unit 210 Drive system control unit 212 Charger control unit 214 Developing device control unit (density adjustment means)
216 Fixing unit control unit 218 Unit loading state management unit 222 Photoelectric sensor (near full sensor)
250 Niyafuru state judgment unit 252 a message output section 254 full determination start instructing section 256 the image data acquisition unit 258 ejecting amount reading unit 260 pixel _{P G} conversion unit (first computing means)
262 pixel _{P H} conversion unit (second computing means)
264 adding unit 266 comparison unit 268 reference value _{P C} storage unit 270 full state determination unit (full determination means)

Claims (3)

The uniformly charged image is provided with charging means for uniformly charging the surface of the image carrier by applying a predetermined voltage to a charging member adjacent to the surface of the image carrier. An electrostatic latent image forming unit that forms an electrostatic latent image by irradiating a carrier with a light beam according to image data; and a developing unit that develops the electrostatic latent image using a developer containing at least toner. A transfer unit that transfers the toner image on the image carrier developed by the developing unit to a recording medium directly or via an intermediate transfer member, and a fixing that fixes the toner image on the recording medium transferred by the transfer unit An image forming apparatus comprising:
A density adjusting means for adjusting a developing density by the developing means by replenishing or discharging toner stored in the developing means;
The transfer residual toner generated when the toner image on the image carrier is transferred or unnecessary toner including the discharged toner generated when discharged by the density adjusting means is taken in, and the image carrier surface and the intermediate transfer member surface are taken up. Cleaning means for cleaning;
A collection box for collecting unnecessary toner taken in by the cleaning means;
A near sensor for detecting a near state in which the amount of unnecessary toner collected in the collection box is a predetermined amount less than an unnecessary toner storage allowable amount in the collection box;
First calculating means for calculating an actual processing amount based on the image data after detecting a near-full state of unnecessary toner in the collection box by the near-full sensor;
Second computing means for converting the amount of toner discharged by the density adjusting means into a pseudo processing amount after the near state of the unnecessary toner in the collection box is detected by the near sensor;
If the sum of the pseudo processing amount and the actual processing amount reaches the reference value, a full determination means for determining said collection box becomes full state,
An image forming apparatus.   2. The image forming apparatus according to claim 1, wherein the actual processing amount and the pseudo processing amount are converted into the number of pixels which is a minimum unit of an image. The uniformly charged image is provided with charging means for uniformly charging the surface of the image carrier by applying a predetermined voltage to a charging member adjacent to the surface of the image carrier. An electrostatic latent image forming unit that forms an electrostatic latent image by irradiating a carrier with a light beam according to image data; and a developing unit that develops the electrostatic latent image using a developer containing at least toner. A transfer unit that transfers the toner image on the image carrier developed by the developing unit to a recording medium directly or via an intermediate transfer member, and a fixing that fixes the toner image on the recording medium transferred by the transfer unit A collection box for taking in and collecting unnecessary toner on the image carrier,
The collection box is partitioned by a partition wall into a first area having a relatively small collection volume and a second area having a relatively large volume.
Wherein the first region, as collected toner amount, when a predetermined amount less Niyafuru state than the toner storage capacity of the entire collection box, a part of the toner stored is accommodated A concave part partitioned by the partition wall for determining the near state is formed,
On the apparatus main body side, a near sensor that detects the presence / absence of toner contained in the recessed portion in the loaded state of the recovery box is disposed,
The partition wall is configured so that the toner stored in the first region becomes toner near the volume of the first region so that the toner is accommodated in the recessed portion. An opening through which toner flows from the region 2 to the first region is formed, and a lower end portion of the opening portion is higher than an upper end portion of the partitioning wall for determining the full state . Collection box.

Images