JP2013182151A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of outputting a stable image by preventing occurrence of an abnormal image by altering the amount of supplied recycle toner in accordance with the output state of a user.SOLUTION: The image forming apparatus comprises: a photoreceptor 10; a charger 11 configured to charge the photoreceptor 10; an exposure part configured to expose the photoreceptor 10 with a laser beam L and form a latent image; a developing device 12 configured to develop the latent image by attaching toner to the latent image; a transfer device 13 configured to transfer a toner image on the photoreceptor 10 to a sheet of paper P; a fixing section configured to fix the toner image on the sheet of paper P; a cleaner 15 configured to scrape toner remaining without being transferred, from the photoreceptor 10; a toner recycle mechanism configured to return scraped toner to the developing device 12 as recycled toner; storage means configured to store the output state of a document when a user uses the image forming apparatus; and adjusting means configured to adjust the amount of recycle toner to be returned to the developing device 12 by the toner recycle mechanism, on the basis of data about the output state stored in the storage means.

Description

  The present invention relates to an image forming apparatus such as a printer, a copying machine, and a facsimile.

  In image forming apparatuses such as copying machines, printers, and facsimiles using an electrophotographic process, various control values (or control values are controlled so as to be maintained) in each process such as charging, exposure, development, transfer, and fixing. Control method). Conventionally, these control values are appropriate by switching with a predetermined control table so as to be appropriate values for various errors such as environment, paper type, and printing rate, or by performing calibration at appropriate intervals. It is designed to be maintained at a reasonable value.

  An example is toner replenishment correction control. In this control, first, several gradation patches are written on the image carrier or intermediate transfer belt, and the respective densities are read. Next, the development bias is changed based on the correlation between each gradation patch and the density, and the image is adjusted to an appropriate image density, and feedback is provided to the toner supply control so that the correlation becomes a predetermined target value. Call. As the predetermined target value, a different value is used depending on the environment and the type / color of the toner.

  However, there are various ways of using image forming apparatuses in the market, and even if switching of control values in the control table as described above or correction by calibration is not always optimal.

  In view of this, a configuration is considered in which control is performed or a set value is changed in accordance with an actual use state of the image forming apparatus. For example, when the standby state in which the fixing heater can be fixed and the energy saving mode in which the energization to the fixing heater is cut off are set, the transition time to the energy saving mode in a time zone in which the image forming apparatus is frequently used It has been proposed to shorten the transition time to the energy saving mode in a time zone in which the image forming apparatus is used less frequently (see Patent Document 1).

  However, in the above-described conventional technology, a limited set value or control is changed such as determining a standby time until the energy saving mode is entered or a timing for performing process control, and feedback regarding many other control values. Is not mentioned.

  For example, in an image forming apparatus with a toner recycling mechanism, the image quality changes depending on the amount of recycled toner. Recycled toner is a system in which toner that has not been transferred is collected and reused. Usually, the amount of charge of recycled toner is often reduced. Therefore, the image quality such as background stains may be deteriorated due to the recycled toner. In the invention described in Patent Document 1, the case where a recycling mechanism is provided is not mentioned. In the initial stage when the amount of recycled toner is small, there is no effect on the image quality. However, with the lapse of time when the amount of recycled toner increases, the image quality as described above may be degraded depending on the amount of recycled toner in the developing device.

  An object of the present invention is to provide an image forming apparatus that prevents the occurrence of abnormal images by changing the replenishment amount of recycled toner according to the output status of the user, and that can output a stable image over time. is there.

  In order to solve the above-described problems, an image forming apparatus of the present invention includes an image carrier, a charging unit that uniformly charges the image carrier, and exposing the image carrier to be latent on the image carrier. An exposure unit for forming an image; a development unit for forming a toner image on the image carrier by developing a toner on the latent image; and a transfer unit for transferring the toner image on the image carrier to a transfer material And a fixing unit for fixing the toner image transferred to the transfer material, and cleaning the image carrier by scraping off toner remaining on the image carrier without being transferred to the transfer material from the image carrier. And a toner recycling mechanism that returns the toner scraped off by the cleaning unit to the developing unit as recycled toner.

  The image forming apparatus of the present invention captures the output status of the transfer material when the user uses the image forming apparatus, and captures the output status data stored in the storage means, The toner recycling mechanism includes adjusting means for adjusting the amount of recycled toner returned to the developing unit based on the output status data.

  According to the above configuration, since the amount of recycled toner returned from the toner recycling mechanism to the developing unit is appropriately adjusted based on the output status data stored in the storage unit, the occurrence of abnormal images can be prevented, and A stable image can be output over time.

  According to the present invention, it is possible to realize an image forming apparatus capable of preventing the occurrence of an abnormal image and outputting a stable image over time by changing the replenished toner replenishment amount according to the output status of the user. it can.

1 is a schematic configuration diagram of a main part of an image forming apparatus according to the present invention. It is a perspective view explaining that a process cartridge is detachable. FIG. 4 is a perspective view illustrating a toner recycling device provided in a process cartridge. FIG. 2 is a partially enlarged view of a developing device disposed below a photoconductor. FIG. 2 is a configuration diagram illustrating a main part in an image forming apparatus, showing a characteristic part of the present invention. It is a graph which shows the number of sheets output according to the time zone of a day.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram showing a main part of a copying machine which is one of image forming apparatuses according to the present embodiment. In the figure, reference numeral 10 denotes a drum-shaped photoconductor as an image carrier, and is provided so as to be rotatable in the direction of arrow A. Around the photoconductor 10, in the order along arrow A, a roller-shaped charging device (charging unit) 11 on the left side, a developing device (developing unit) 12 on the lower side, and a transfer device (on the right side) A transfer unit 13 and a sheet separating device 14 are disposed above, and a cleaning device 15 is disposed above.

  When taking a copy, as is well known, after setting a document on a contact glass (not shown), the copy switch is pressed and an image of the document is read by an optical reader (not shown). Paper (transfer material) P is fed into the sheet.

  On the other hand, the photoconductor 10 rotates in the direction of arrow A at a predetermined peripheral speed, and along with the rotation, the charging device 11 cleaned by the cleaning pad 16 contacts the surface of the photoconductor 10 and moves in the direction of arrow B. The surface of the photoconductor 10 is uniformly charged while rotating. Then, writing is performed by irradiating the surface of the photoconductor 10 with laser light L from an optical writing device (exposure unit) (not shown) to form an electrostatic latent image of the read document image on the photoconductor 10. Subsequently, when the toner passes through the vicinity of the developing device 12, toner is attached to the electrostatic latent image to sequentially visualize the electrostatic latent image, and as described above, the photosensitive member 10 and the transfer device 13 are used. The paper P is conveyed between them, and the toner image formed by making it visible is transferred onto the paper P by the transfer device 13.

  After the transfer, the sheet P is discharged from the sheet separating device 14 and separated from the electrostatically adhering photoconductor 10, conveyed to a fixing device (not shown), and the transferred image is fixed by the fixing device. The paper is discharged to a paper discharge section (not shown). Note that a separation claw may be provided in place of the sheet separation device 14 to mechanically separate the sheet P from the photoreceptor 10.

  On the other hand, after the image transfer, the residual toner remaining on the surface of the photoconductor 10 is scraped off by the cleaning blade 17 of the cleaning device 15 to clean the surface, and then the charge is removed by a neutralization lamp (not shown), and the surface potential is initially set. It becomes.

  By the way, in this embodiment, the photosensitive member 10, the charging device 11, the developing device 12, and the cleaning device 15 are accommodated in one cartridge case 19, and these devices constitute a process cartridge 20. As shown in FIG. 2, the process cartridge 20 can be inserted into and removed from the copying machine apparatus body 18 in the directions of arrows C1 and C2 from the front side with both hands.

  In such a process cartridge 20, the developing device 12 has a developer accommodating portion 21 on the lower side and a developer carrying portion 22 on the upper side, as shown in FIG. The developer storage unit 21 stores a dry two-component developer (hereinafter simply referred to as a developer) composed of a carrier and a toner, and the developer is conveyed to the developer carrying unit 22 while being stirred by the stirring member 23. The Although not shown, the developer container 21 is provided with a toner concentration sensor that detects the mixing ratio of the toner in the developer and the carrier.

  A developing sleeve (developer carrying member) 28 is disposed in the developer carrying portion 22 at a position facing the photoconductor 10 through the upper developing window 27. The developing sleeve 28 has a magnet inside and rotates in the direction of arrow D. In addition, the developer carrying unit 22 is provided with a developing doctor (developer regulating member) 29 that controls the amount of developer supplied to the photoreceptor 10.

  The cleaning device 15 disposed above the photoreceptor 10 includes a toner recycling device (toner recycling mechanism) that returns residual toner scraped off by the cleaning blade 17 to the developing device 12 in the cleaning case portion 19a of the cartridge case 19. 32 is provided. The toner recycling device 32 includes a recovery blade 30 that scrapes up the residual toner scraped off by the cleaning blade 17, and a toner transport member 31 that transports the residual toner scraped up by the recovery blade 30 (see also FIG. 3). .

  As shown in FIG. 3, the toner conveying member 31 is disposed above the photoconductor 10 along the axial direction of the photoconductor 10. The toner conveying member 31 is made of a pipe or the like, and has a spiral groove formed on the outer peripheral surface thereof.

  FIG. 4 is a partially enlarged view of the developing device 12 disposed below the photoconductor 10. As shown in FIG. 4, in the developing device 12, a driving motor (not shown) is driven at the time of copying, and the driving force is transmitted to the developing sleeve 28, rotating the developing sleeve 28 and rotating the stirring member 23. And stir the developer. Thereby, the toner and the carrier can be conveyed to the developing sleeve 28 while being frictionally charged. At this time, a predetermined bias is applied to the developing sleeve 28, and the toner in the developer is electrostatically attached to the surface of the photoconductor 10, and the latent image on the surface of the photoconductor 10 is visualized. To do.

  On the other hand, as shown in FIG. 3, the cleaning device 15 is provided with a gear 35, a gear 36, a gear 37, and a gear 38. The gear 37 is one end of the collection blade 30, and the gear 38 is one end of the toner conveying member 31. It is attached to each part. The gear 35 is connected to a recycle toner supply motor (not shown). When the recycled toner replenishing motor is driven to rotate, the rotational force is transmitted to the gears 37 and 38 via the gears 35 and 36, and the recovery blade 30 and the toner conveying member 31 are rotated.

  As described above, the residual toner is scraped off from the photoreceptor 10 by the rotation of the collection blade 30, and the residual toner scraped off by the rotation of the toner transport member 31 is transported along the toner transport member 31 as indicated by an arrow E. Then, they are collected on the front side in the cleaning case portion 19a (the diagonally lower left side in FIG. 3), and then returned to the developer accommodating portion 21 of the developing device 12 by gravity as indicated by an arrow F.

  Here, when the replenishment amount of the recycled toner is controlled, it is adjusted by controlling the rotation time of the recycle toner replenishment motor. This is not limited to the form of the present embodiment, and any form may be used as long as it is a means for changing the replenishment amount, such as providing a rotation speed of the motor and a shutter member in the recycled toner path.

  Next, the characteristic part of a present Example is demonstrated.

  In this embodiment, as shown in FIG. 5, a storage unit (storage unit) that stores the output status of the sheet (transfer material) P when the user uses the image forming apparatus 1 inside the image forming apparatus 1. 2 is provided. In addition, the amount of recycled toner that the toner recycling device 32 returns to the developing device 12 based on the output status data is acquired inside the image forming apparatus 1 and the output status data stored in the storage unit 2 is captured. A control unit (adjusting means) 3 for adjusting the above is provided. Here, every time a document (paper P) is output, the number of documents (paper P) is counted and stored in the storage unit 2, and data on the number of documents (paper P) output for each time period is calculated. The The control unit 3 performs recycle toner replenishment control based on the data.

  For example, when there is a user who has an output status as shown in FIG. 6, it is possible to predict the time when the output will be completed. When printing is finished, the printer is left standing until it is output the next day. Since the characteristic of the recycled toner is a toner having a low charge amount, background dirt is likely to occur in the output after being left unattended. Therefore, by reducing the supply amount of the recycled toner before the output of the day ends from the output data for each time period, it is possible to prevent background contamination on the next day (after leaving).

  Here, the output state of FIG. 6 will be described in detail. In FIG. 6, the horizontal axis indicates the time in 1-hour increments (from 0:00 to 24:00), and the vertical axis indicates the number of output documents (paper P) at each time. As can be seen from FIG. 6, the number of output sheets is 0 from 0:00 to 8:00, but 30 sheets at 9 o'clock, 50 sheets at 10 o'clock, 48 sheets at 11 o'clock, and 10 sheets at 12 o'clock. At 12 o'clock it will be lunch break, so the number of output sheets is decreasing. 20 at 13 o'clock, 30 at 14 o'clock, 70 at 15 o'clock, 50 at 16 o'clock, 30 at 17 o'clock, 35 at 18 o'clock, 20 at 19 o'clock, 25 at 20 o'clock, 10 at 21 o'clock, 10 at 22 o'clock It is a sheet. The number is 0 at 23:00 and 24:00.

  In this embodiment, the storage unit 2 shown in FIG. 5 is configured so that the date and day of the week can be stored together with the number of output sheets (paper P). When it is assumed that the device is left for a long time, such as before a weekend or a long holiday, the replenishment amount of the recycled toner is reduced at a stage considerably earlier than the output end time ascertained from FIG. As a result, the amount of recycled toner in the developing device 12 immediately before leaving for a long time can be reduced, so that abnormal images such as background stains after being left can be prevented.

  In the present embodiment, the control unit 3 shown in FIG. 5 is configured to receive print rate data indicating how many characters have been printed on the output document (paper P). The control unit 3 determines the replenishment amount of the recycled toner based on the received printing rate data. Then, the control unit 3 controls the transport of the recycled toner based on the replenishment amount, and adjusts the refill toner supply amount. That is, the control unit 3 performs control to increase the amount of recycled toner when the printing rate is high and to decrease the amount of recycled toner when the printing rate is low. As a result, even when the printing rate is low, the amount of recycled toner in the developing device 12 can be stabilized, and a stable image can be obtained even for users with extremely biased printing rates.

  Further, in the present embodiment, the storage unit 2 is configured to be able to store, for example, the number of output sheets per day, the printing rate, and the number of output sheets per time zone for 30 days before. In this way, the control unit 3 can grasp the tendency of the average number of output sheets and the printing rate for each day of the week and each time zone based on these data. Depending on the user, there is a user who concentrates the output at the time of a meeting held regularly or outputs almost the same manuscript, etc. The trend can be grasped more accurately. Thereby, more accurate control of the recycled toner amount can be performed, and a stable image can be obtained.

  Further, in the present embodiment, the control unit 3 is configured to be able to calculate the amount of recycled toner for the day by grasping the number of printed sheets for the previous day and the output printing rate. For example, assume that the number of output sheets for the day is N and the average printing rate for the day is A%. If the transfer rate of the image forming apparatus is B%, the amount of recycled toner generated on that day is N × A × (100−B). Based on the amount of the recycled toner, the total amount of recycled toner to be supplied the next day is determined. This replenishment amount may be arbitrarily set for each system of the image forming apparatus. Here, since the replenishment amount of the recycle toner is changed according to the use state according to the user's use state, there is a concern that the recycle toner is accumulated in the recycle toner path and abnormal images such as defective cleaning may occur. If comprised like this, the said concern can be wiped out.

  As mentioned above, although the Example of this invention has been explained in full detail with drawing, the said Example is only the illustration of this invention, and this invention is not limited only to the structure of the said Example. Needless to say, changes in design and the like within the scope of the present invention are included in the present invention.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Memory | storage part (memory | storage means)
3 Control unit (adjustment means)
10 Photoconductor (image carrier)
11 Charging device (charging unit)
12 Development device (development unit)
13 Transfer device 15 Cleaning device (cleaning part)
17 Cleaning blade 20 Process cartridge 30 Collection blade 31 Toner transport member 32 Toner recycling device L Laser light from optical writing device P Paper (transfer material)

JP 2004-101919 A

Claims (6)

An image carrier;
A charging unit for uniformly charging the image carrier;
An exposure unit that exposes the image carrier to form a latent image on the image carrier;
A developing unit that attaches toner to the latent image and develops the toner image on the image carrier;
A transfer portion for transferring a toner image on the image carrier to a transfer material;
A fixing unit for fixing the toner image transferred to the transfer material;
A cleaning section for cleaning the image carrier by scraping off the toner remaining on the image carrier without being transferred to the transfer material;
An image forming apparatus comprising a toner recycling mechanism that returns the toner scraped off by the cleaning unit to the developing unit as recycled toner,
Storage means for storing the output status of the transfer material when the user uses the image forming apparatus;
The output unit stores the output status data stored in the storage unit, and based on the output status data, the toner recycling mechanism includes an adjustment unit that adjusts the amount of recycled toner to be returned to the developing unit. An image forming apparatus.   The output status is the number of output sheets of the transfer material for each time zone, and the adjusting means increases the amount of the recycled toner when the output number is large, and the amount of the recycled toner when the output number is small. The image forming apparatus according to claim 1, wherein the amount is reduced.   The output status is the number of output sheets for each date or day of the transfer material, and the adjusting means increases the amount of the recycled toner when the output number is large, and the recycle when the output number is small. The image forming apparatus according to claim 1, wherein the toner amount is reduced.   The output status is print rate data indicating how many characters are printed on the transfer material, and the adjusting means increases the amount of the recycled toner when the print rate is high, and the print rate is low. 2. The image forming apparatus according to claim 1, wherein the amount of the recycled toner is reduced.   5. The image forming apparatus according to claim 1, wherein the adjustment unit adjusts the amount of the recycled toner based on at least an output state before the previous working day.   The said adjustment means determines the total amount of the replenishment amount of the said recycled toner on the day of an operation day from the relationship between the number of output sheets of a previous operation day, and printing rate data. The image forming apparatus described.