JP2005221989A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus realizing suppression of deterioration in image quality due to poor cleaning by detecting chip of a cleaning blade at an early stage to suppress expansion of the chip. <P>SOLUTION: A film 51 for stopping and accumulating the remaining toner on the photoreceptor drum 3 having passed the chip part of the cleaning blade 41 is stuck on the side face (a position rather downstream of a photoreceptor drum 3 in the rotary direction than the cleaning blade 41) of an electrostatic charger. Then, the toner accumulated by the film 51 is detected by a detection sensor 6 composed of optical sensors. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention is an image forming apparatus for cleaning a developer remaining on an image carrier after image formation by using a cleaning member, and in particular, suppressing an increase in chipping at a contact portion of the cleaning member with the image carrier. The present invention relates to a technique for suppressing image quality deterioration due to poor cleaning.

  Generally, an electrostatic copying machine forms an electrostatic latent image on the surface of a photosensitive drum, develops the electrostatic latent image with toner, forms a toner image, and transfers the formed toner image to a recording sheet. Thus, an image is formed and toner remaining on the surface of the photosensitive drum after image formation is cleaned by a cleaning device to remove the residual toner and prepare for the next image formation.

As a cleaning device having such a configuration, for example, a mainstream device that forcibly scrapes the residual toner adhering to the surface of the photosensitive drum by pressing the edge portion of the cleaning blade made of elastic rubber or the like on the surface of the photosensitive drum, for example. It has become.
In the method of pressing the cleaning blade, the amount of toner interposed between the cleaning blade and the photosensitive drum is drastically reduced by, for example, extremely reducing the amount of toner used when copying a large number of documents with very few characters, For this reason, the frictional force at the contact portion between the two increases, and the amount of deformation of the edge of the cleaning blade increases, and a minute chipping (deletion) may occur in part. Even if such chipping is minute at first, it gradually increases with time due to stress concentration on the chipped part.

  If the cleaning blade has a small chip of, for example, about several μm to several tens of μm, even if the residual toner is scraped through the chipped portion and remains on the photosensitive drum, the amount is extremely small. In many cases, the image quality of the formed image is not affected. However, when the chipping becomes large, the image appears as visible to the human eye, and eventually the image quality is deteriorated.

  It has been found that the occurrence or enlargement of chipping of the cleaning blade is largely due to an increase in the frictional force at the contact portion between the cleaning blade and the photosensitive drum. By forming a toner pattern on the photosensitive drum and cleaning it with a cleaning blade, a large amount of toner is supplied as a lubricant to the contact portion between the cleaning blade and the photosensitive drum, and the frictional force between the two is reduced. The occurrence of chipping of the cleaning blade and the expansion of the chipping are suppressed.

Further, regarding the chipping of the cleaning blade, for example, in Patent Document 1, a predetermined toner pattern is formed on the rotating photosensitive drum, and after this is cleaned with the cleaning blade, the presence or absence of residual toner on the photosensitive drum is detected. Thus, there has been proposed a technique for detecting a chipping of the cleaning blade and informing the user of this.
JP-A-8-179574

As described above, when a minute chipping occurs in the cleaning blade, it is preferable to supply toner to the cleaning blade frequently in order to suppress the enlargement as much as possible.
However, the supplied toner does not contribute to copying at all and is used only for reducing the frictional force between the cleaning blade and the photosensitive drum. Therefore, it is necessary to equip a container for storing a large amount of toner for supply in addition to the original toner for copying, leading to an increase in toner consumption and an increase in the size of the apparatus.

  On the other hand, if the technology of Patent Document 1 is used and toner is supplied when a chipping of the cleaning blade is detected, the amount of toner to be supplied can be reduced while suppressing the expansion of the chipping. However, since the technique of Patent Document 1 directly detects residual toner on a rotating photosensitive drum using a reflective optical sensor, the chip of the cleaning blade is minute, and the chipped portion is rubbed. If the amount of toner that falls out is extremely small, detection is impossible in practice, and when the amount of toner that can be detected is reached, chipping has already expanded and defective cleaning has occurred, resulting in a loss. End up.

  The present invention has been made in view of the above problems, and by detecting the chipping of the cleaning blade at an early stage, it is possible to suppress the progress of the expansion of the chipping and to suppress image quality deterioration due to poor cleaning. An object of the present invention is to provide an image forming apparatus.

  In order to achieve the above object, an image forming apparatus according to the present invention is an image forming apparatus that forms an image by transferring a developer image formed on an image carrier onto a transfer material. A cleaning member that cleans the surface of the body, and a collection unit that contacts the surface of the image carrier and has a collection member that collects the developer remaining on the image carrier without being cleaned by the cleaning member; And a detecting means for detecting the developer collected by the collecting member.

When the value of the detection signal from the detection means indicates that the amount of the collected developer exceeds the first predetermined amount, the cleaning member and the surface of the image carrier And a developer supplying means for supplying the developer between the two.
Further, the detection means detects the developer when a predetermined time is reached.

Further, the predetermined time is when the number of times of image formation reaches a predetermined number.
The predetermined time is when a predetermined time elapses after the image forming operation is started.
Furthermore, when the value of the detection signal from the detection means indicates that the amount of collected developer exceeds the second predetermined amount, it is time to replace the cleaning member. Or it is characterized by providing a notification means for notifying the user that the replacement time is near.

Further, the notifying means is a display means, and notifies the user that the replacement time or the replacement time is near. Further, the contact portion of the collecting member with the image carrier Is longer than the cleaning width of the surface of the image carrier by the cleaning member.
Further, the detection means includes a detection sensor and a moving means for moving the detection sensor along a contact portion of the collection member with the surface of the image carrier, and the detection sensor is moved along the contact portion. The developer collected on the collecting member is detected while being moved.

Further, the collecting member is made of a light-transmitting member, and the detecting means includes a light emitting element and a light receiving element, and a light beam emitted from the light emitting element is transmitted to the image carrier of the collecting member. The developer is detected by irradiating the contact portion of the light and receiving the reflected light or transmitted light with the light receiving element.
An exposure unit that exposes the surface of the image carrier to form a latent image on the surface of the image carrier; and a developing unit that develops the latent image on the surface of the image carrier to form a developer image. The exposure means also serves as the light-emitting element, a first direction in which a light beam emission direction is directed to an exposure position on the image carrier, and the image carrier of the collection member; It is configured to be switchable in the second direction toward the contact portion.

Further, the collecting member has a film-like or blade-like member whose tip portion contacts the surface of the image carrier and stops and accumulates the developer remaining on the image carrier at the contact portion. The detecting means detects the developer accumulated in the contact portion of the film-like or blade-like member with the image carrier.
The collecting member is a web-shaped member, and the collecting means includes a supply roller that supplies the web-shaped member, and a winding roller that winds the web-shaped member. A portion between the supply roller and the take-up roller in the shape-shaped member is brought into contact with the surface of the image carrier, and the developer is stopped and adhered to the contact portion. A developer adhering to a contact portion of the web-shaped member wound up by the take-up roller with the image carrier is detected.

Further, the cleaning member is a cleaning blade whose front end is in contact with the surface of the image carrier to clean the surface of the image carrier, and the image carrier is formed in a drum shape or a belt shape. It is characterized by being.
The image carrier is a rotating body, and the collecting member is developed by developing from a cleaning position where the surface of the image carrier is cleaned by the cleaning member in the rotation direction of the image carrier. It is arranged between the developing position where the developer image is formed on the body.

  As a result, the developer accumulated by the collecting member can be detected using the detection means. Accordingly, since the developer on the image bearing member such as the rotating photosensitive drum is directly detected as in the conventional case, if the cleaning member has a small chip, the amount of the developer that rubs through the chip is too small. The occurrence of such a minute chip can be detected at an early stage without occurrence of being unable to be detected.

Hereinafter, an example in which an embodiment of an image forming apparatus according to the present invention is applied to a monochrome laser printer (hereinafter simply referred to as “printer”) will be described.
FIG. 1 is a diagram illustrating a schematic configuration of the entire printer.
This printer forms (prints) an image on a recording sheet as a transfer material based on image data input from an external device such as a personal computer. When image data is input from an external device, the control unit 1 converts this into a laser diode drive signal, and drives a laser diode (not shown) inside the printer head 10. The laser beam L emitted from the laser diode is deflected by the folding mirror 2 and then exposes the surface of the photosensitive drum 3 as an image carrier in the main scanning direction at the exposure position E.

Around the photosensitive drum 3, a cleaner 4, a charging charger 5, a developing device 7, a transfer charger 8, and the like are arranged.
The cleaner 4 includes a cleaning blade 41. The cleaning blade 41 is held in a counter direction with respect to the rotation direction A of the photosensitive drum 3 with its tip (edge) being in contact with the surface of the photosensitive drum 3, and residual toner on the photosensitive drum 3. Scraping off and removing (cleaning) The residual toner scraped off by the cleaning blade 41 is collected in a collection container (not shown).

Before the exposure with the laser beam L, the photosensitive drum 3 is charged with a charging charger 5 by removing residual toner and the like with a cleaner 4. When the surface of the photosensitive drum 3 that is charged and rotated in the direction of arrow A is exposed by the laser beam L, an electrostatic latent image is formed, and this electrostatic latent image is developed by the developing device 7 to be a toner image ( A developer image).
On the other hand, a recording sheet is fed from the sheet feeding cassette 20 by a pickup roller 21 and a timing roller 22. This recording sheet is conveyed by the transfer belt 23 to a transfer position directly below the photosensitive drum 3. At the transfer position, the toner image on the photosensitive drum 3 is transferred to the recording sheet by the action of the transfer charger 8. The recording sheet to which the toner image has been transferred is further conveyed by the transfer belt 23 and the conveyance belt 24, and after the toner is fixed by the fixing device 25, the recording sheet is discharged to the discharge tray 28.

A display unit 12 is disposed at a position on the front side of the apparatus where the user can easily operate. On the display unit 12, a message indicating various information such as the presence or absence of a recording sheet is displayed.
A flexible transparent or translucent (translucent) film 51 made of polyurethane is attached to the side surface of the charging charger 5 on the exposure position E side.
FIG. 2 is an enlarged view of the film 51 and its periphery, and FIG. 3 is a side view of the film 51 viewed from the direction of arrow B in FIG.

  As shown in both figures, the film 51 has a leading end portion 511 that contacts the photosensitive drum 3 in the trail direction (pulls the surface of the photosensitive drum 3) and has a length in the main scanning direction (with the photosensitive drum 3). (W2> image forming width W3), and after the cleaning blade 41 is cleaned, the length W1 of the contact portion) is substantially the same as the length (cleaning width) W2 of the cleaning blade 41 in the main scanning direction. The uniform contact is made over the entire area of the surface of the photosensitive drum 3, the passage of the residual toner that has passed through the cleaning blade 41 is prevented, and the toner is accumulated at the contact portion with the surface of the photosensitive drum 3. .

  More specifically, one main surface of the film 51 is brought into surface contact with the surface of the photosensitive drum 3 by a predetermined amount, and the residual toner adhering to the surface of the photosensitive drum 3 is pulled away by the contact pressure, and the toner itself has. The toner is accumulated in the surface contact portion by adhesion force with the film 51 (due to releasability, etc.), coulomb force due to static electricity generated between the film 51 as an insulating member and the photosensitive drum 3. is there. In this sense, the film 51 functions as a collecting member that collects residual toner on the photosensitive drum 3 that has passed through the cleaning blade 41.

As a result, when a minute chip occurs at any position of the edge 411 of the cleaning blade 41 in the main scanning direction, and the residual toner passes through the position, the toner is transferred between the film 51 and the photosensitive drum 3. The contact portion is blocked by the portion of the chip at the same position in the main scanning direction and gradually accumulated.
The detection sensor 6 is a reflection type optical sensor having a light emitting element 61 and a light receiving element 62, and is held on the rail 13 so as to be slidable in the main scanning direction, and is connected to the rotation shaft of the drive motor 11 (FIG. 1). It is configured to be able to move between the position of X0 and the position of Xn by a so-called screw feed mechanism by engaging with a screw member (not shown).

  The detection sensor 6 emits a light beam from the light emitting element 61 while moving from the position of X0 to the position of Xn in the residual toner detection process described later, and the film 51 out of the light emitted from the light emitting element 61. The light receiving element 62 receives the light that passes through the front end portion 511 and hits the surface of the photosensitive drum 3 and is reflected and returned, and outputs a detection signal (electric signal) corresponding to the amount of light to the control unit 1. Here, the voltage value of the detection signal output from the detection sensor 6 has a half-proportional relationship with the amount of return light.

For example, in the state where the edge 411 of the cleaning blade 41 is not chipped and the toner is not scraped off, no toner is accumulated at the contact portion between the film 51 and the surface of the photosensitive drum 3. Most of the light emitted from the element 61 returns as reflected light from the photosensitive drum 3, and the output voltage of the light receiving element 62 decreases.
On the contrary, when the edge 411 of the cleaning blade 41 is chipped and the toner is scraped off, the toner is accumulated at the contact portion between the film 51 and the surface of the photosensitive drum 3, and the accumulated amount is large. As a result, the amount of reflected light from the photosensitive drum 3 decreases, and the output voltage of the light receiving element 62 increases.

As shown in FIG. 4, the control unit 1 includes a CPU 101, a communication interface (I / F) unit 102, a ROM 103, a RAM 104, and a detection data storage unit 105.
The communication I / F unit 102 is an interface for connecting to a LAN such as a LAN card or a LAN board.
The ROM 103 stores a program related to an image forming operation by the photosensitive drum 3 and the printer head 10 and a recording sheet feeding operation from the paper feeding cassette 20. In addition, a program related to residual toner detection processing is stored.

The CPU 101 reads out a necessary program from the ROM 103 and controls the image forming operation and the like uniformly while taking a timing to execute a smooth printing operation. Also, residual toner detection processing is executed.
The RAM 104 is a volatile memory and serves as a work area when the CPU 101 executes a program.

The detection data storage unit 105 is a nonvolatile memory such as an EEPROM and stores data indicating a detection signal sent from the light receiving element 62 in the residual toner detection process.
FIG. 5 is a flowchart showing the content of the residual toner detection process executed by the CPU 101. In this residual toner detection process, every time a printing operation (the printing operation when one printing operation is performed on one recording sheet) is performed a predetermined number of times, for example, 100 times, the interval between image formation operations (image formation) Is executed).

As shown in the figure, the CPU 101 drives the detection sensor 6 (step S1). Thereby, a light beam is emitted from the light emitting element 61.
Next, the drive motor 11 is driven, and the detection sensor 6 is moved (step S2). Specifically, when the movement is started from the position X0 (home position) and the position Xn is reached, a reciprocating operation is performed in which the drive motor 11 is reversely rotated and returned to the position X0 again. Here, a stepping motor is used as the drive motor 11, the number of steps of the motor corresponding to the distance from the position X0 to Xn is obtained in advance, and the data is stored in the ROM 102. When the drive motor 11 is rotationally driven by the number of steps, the detection sensor 6 reaches the position Xn, and when the drive motor 11 is reversely rotated by the same number of steps, it is determined that the drive motor 11 has returned to the position X0, and the drive motor 11 is stopped. It is something to be made. In this sense, the control unit 1, the drive motor 11, the rail 13, etc. function as moving means for moving the detection sensor 6 along the contact portion between the film 51 and the photosensitive drum 3.

The CPU 101 receives a detection signal sent from the moving detection sensor 6, samples the received detection signal at a predetermined timing, and X0, X1, X2,... Xn-1, A detection value at each position of Xn is obtained (step S3). FIG. 6 is a graph showing an example of the voltage waveform of the detected value at each position of the film 51.
The CPU 101 refers to the detection value at each position, and determines whether or not there is a place where the voltage value is equal to or greater than the predetermined value T (step S4). This predetermined value T is derived from an experiment or the like in advance as a value indicating that the amount of toner that is scraped off due to the chipping of the cleaning blade 41 increases and image quality deterioration occurs. Therefore, if the detected value at a certain position is equal to or greater than the predetermined value T, the edge 411 of the cleaning blade 41 has a large chip that causes image quality degradation at the same position as the certain position in the main scanning direction. On the other hand, if the detected value at any position is smaller than the predetermined value T, it means that there is no chipping at all, or it is generated but is minute. Data indicating the predetermined value T is stored in the ROM 102.

  If it is determined that the detected value at each position is not equal to or greater than the predetermined value T (ie, “NO” in step S4), the cleaning blade 41 has a large chip that causes image quality degradation. Although there is no possibility that a minute chipping has occurred, the following processing is executed. That is, data indicating a detection value at the time of the previous residual toner detection process is read from the detection data storage unit 105 (step S5). In the residual toner detection process, each time the process is performed, data indicating the detection value at the time of the process is overwritten and saved in the detection data storage unit 105 (see step S11), thereby the previous process. The data at can be read.

  When the data indicating the detection value at the previous residual toner detection process is read, the difference between the previous detection value and the current detection value is calculated for each position X0, X1,... (Step S6). For example, in FIG. 6, when “P (dashed line)” is obtained as the voltage waveform at the previous detection and “R (solid line)” is obtained as the voltage waveform at the current detection, the difference is obtained for each position other than the position Xr. Although d is almost zero (the voltage is almost equal between the previous time and the current time), the difference D is large for the position Xr. This is because between the previous detection time and the current detection time, a minute chipping occurred in the portion corresponding to the position Xr of the edge 411 of the cleaning blade 41 in the main scanning direction, and the chipping portion was rubbed through. This shows that toner is accumulated at the position Xr of the film 51.

  Then, it is determined whether or not the calculated difference is greater than or equal to a predetermined value S (step S7). The predetermined value S is a threshold value for determining whether or not toner should be forcibly supplied to the edge 411 in order to suppress the expansion of the chip when the chip 411 of the cleaning blade 41 has a small chip. Are derived from experiments and the like in advance. Here, data indicating the predetermined value S is stored in the ROM 102.

In this sense, the process of step S7 is a process of determining whether or not the detected value by the detection sensor 6 indicates that the accumulated amount of residual toner exceeds a predetermined amount that requires toner supply. It can be said that it represents an example.
If it is determined that the difference ≧ predetermined value S (difference D ≧ predetermined value S (however, difference d <predetermined value S) as in the example of FIG. 6) (“YES” in step S7), it is necessary to forcibly supply toner. A toner pattern having a predetermined halftone is formed on the photosensitive drum 3 (step S9).

FIG. 7 is a perspective view when the toner pattern is formed on the photosensitive drum 3 as viewed from the direction of the arrow C in FIG. In the example shown in the figure, only the photosensitive drum 3, the cleaning blade 41, and the film 51 are shown, and other members such as the charging charger 5 and the developing device 7 are omitted for easy understanding of the toner pattern formation position. Yes.
As shown in the drawing, the photosensitive drum is arranged such that the width of the toner pattern is W4 around the position Xr 'where the position of the cleaning blade 41 in the main scanning direction corresponds to the position Xr on the film 51. 3 is formed in a band shape along the rotation direction. Specifically, a latent image of the toner pattern is formed on the photosensitive drum 3 by the charging charger 5 and the printer head 10 and developed by the developing device 7.

  The toner pattern formed on the photosensitive drum 3 is scraped off and cleaned at the cleaning blade 41. At this time, a minute chipped portion generated at the position Xr ′ of the edge 411 of the cleaning blade 41 is obtained. In addition, the toner is supplied, and the frictional force generated between the edge 411 and the surface of the photosensitive drum 3 is reduced, thereby suppressing the expansion of the chip. In this sense, the control unit 1, the photosensitive drum 3, the charger 5, the developing device 7, the printer head 10, and the like supply a developer (toner) between the cleaning blade 41 and the photosensitive drum 3. It functions as a means.

  Returning to FIG. 5, in step S <b> 10, the CPU 101 stops the rotational driving of the photosensitive drum 3 and ends the toner pattern forming operation when a predetermined time has elapsed from the start of toner pattern formation. This predetermined time is a time required for supplying a sufficient amount of toner as a lubricant to the minute chipped portion generated at the edge 411, and is obtained in advance by experiments or the like. Note that data indicating the predetermined value is stored in the ROM 102.

On the other hand, if it is determined that the difference <predetermined value S (“NO” in step S7), a minute chip is generated on the edge 411 of the cleaning blade 41, but it is not necessary to forcibly supply the toner because it is extremely small. Then, the process proceeds to step S11.
In step S11, data indicating the current detection value at each position obtained by sampling in step S3 is overwritten and stored in the detection data storage unit 105, and the process ends.

  On the other hand, if the detected value at any position is greater than or equal to the predetermined value T in step S4 (when the waveform of the alternate long and short dash line U in FIG. 6 is obtained) (“YES” in step S4), cleaning is performed. Since the blade 41 has a large chip that causes image quality deterioration, a message indicating that it is time to replace the cleaning blade 41 is displayed on the display unit 12 (step S12), and the process proceeds to step S11. In this sense, the process of step S4 indicates whether or not the detection value by the detection sensor 6 indicates that the accumulated amount of residual toner exceeds a predetermined amount that requires the replacement display of the cleaning blade 41. It can be said that it represents an example of processing to be determined.

  As described above, in the present embodiment, the toner that has passed through the cleaning blade 41 is stopped and accumulated by the film 51, and the accumulated toner is detected by the optical sensor. Accordingly, since the residual toner on the rotating photosensitive drum is directly detected as in the prior art, if the cleaning blade has a small chip, the amount of toner that rubs through the chip is too small to detect the residual toner. The occurrence of such a small chip can be detected at an early stage, and the toner can be supplied to the cleaning blade with the detection. As a result, it is not possible to detect minute chips on the cleaning blade, so it is not necessary to frequently supply toner to the cleaning blade regardless of the presence or absence of chipping. There is no need to arrange it in the apparatus in advance. Further, since the toner can be supplied at an appropriate timing while the cleaning blade has a small chip, it is possible to suppress the expansion of the chip and suppress the deterioration of the image quality, that is, to maintain the image quality level.

  In the above description, the residual toner detection process is executed every time the printing operation is performed a predetermined number of times. However, the execution timing of the residual toner detection process is not limited to this. For example, when a predetermined time elapses in the standby state from when power is supplied to the apparatus until the printer is ready for printing (when the standby state is long and the frequency of printing operations is low), the image forming condition is the document Print for originals with a black-and-white ratio (area ratio of image parts such as characters to the original size) smaller than a predetermined value (specifically, originals with a small amount of characters and mostly white background) A case where the operation is executed a predetermined number of times (for example, 50 times) (when the amount of toner used becomes extremely small) may be considered. The document black-and-white ratio is obtained, for example, by counting the total number of pixels of the document and the number of black pixels and calculating the ratio.

The execution time may be changed depending on the installation environment. For example, some cleaning blade materials may be easily chipped in a high-temperature and high-humidity environment. In such a case, the execution interval may be shortened in a high-temperature and high-humidity environment compared to normal temperature and normal humidity and low temperature and low humidity. Conceivable.
Further, the detection of residual toner and toner supply are performed continuously, but they may be performed separately. For example, residual toner detection (steps S1 to S7) is performed during a printing operation (after a predetermined time has elapsed from the start of printing), and when toner supply is necessary, the toner supply operation (step S8 to S11) are executed. In this way, the toner supply operation can be started immediately after the end of the printing operation, and the time required for detecting the residual toner can be shortened.

(Modification)
As described above, the present invention has been described based on the embodiment. However, the present invention is not limited to the above-described embodiment, and the following modifications may be considered.
(1) In the above embodiment, the example in which the film 51 is used as the collecting member for collecting the residual toner on the photosensitive drum 3 that has passed through the cleaning blade 41 has been described. However, the present invention is limited to the film. There is no. For example, a transparent or translucent blade-like material made of rubber or the like can be used instead of the film. In this case, in order to prevent the blade-shaped member itself from being chipped due to friction with the photosensitive drum 3, it is preferable that the blade-shaped member is brought into contact with the photosensitive drum 3 in the trail direction.

A web-like member (hereinafter referred to as “web”) can also be used as a collecting member. FIG. 8 is a diagram illustrating a configuration example of the detection unit 30 that collects and detects toner using a web.
As shown in the figure, the detection unit 30 includes a web 33, a supply roller 31 that supplies the web 33, a winding roller 32 that winds the web 33, and the web 33 between the supply roller 31 and the winding roller 32. A pressing roller 34 that presses a part of the surface of the photosensitive drum 3 and a detection sensor 35 are provided.

  The web 33 is made of a woven fabric of fiber or a nonwoven fabric such as polyester or nylon, and the width in the main scanning direction is the same W1 as that of the film 51. The detection sensor 35 is composed of an optical sensor similar to the detection sensor 6, but here is not configured to move in the main scanning direction, but has a configuration in which a large number of optical sensors are arranged in the main scanning direction. The number of optical sensors is determined based on the detection width of the sensor in the main scanning direction so that the toner collected by the web 33 can be detected on the web 33 over the entire width in the main scanning direction.

In such a configuration, the toner on the photosensitive drum 3 that has passed through the cleaning blade 41 is prevented from passing and accumulated at the contact portion of the web 33 with the photosensitive drum 3.
The web 33 is wound up by a predetermined amount by the winding roller 32 every time the number of times of printing reaches a predetermined number of times, and the accumulated toner is wiped off by the web 33 by the winding and collected. When the position detected by the detection sensor 35 is reached, the amount is detected. In this sense, the detection unit 30 functions as a collection unit having a web as a collection member.

  Each optical sensor of the detection sensor 35 sends a detection signal corresponding to the amount of toner attached to the web 33 to the control unit 1. The control unit 1 receives the detection signals from the respective optical sensors, and detects at which position in the main scanning direction on the web 33 the toner is accumulated based on the received detection signals. Thereafter, the same processing as in steps S4 to S12 is performed, and operations such as toner supply to the cleaning blade 41 are performed.

Thus, by winding up the web 33 by a predetermined amount at each detection time, the toner does not continue to be accumulated in a specific portion of the web. Therefore, as in the above-described embodiment, the previous detection time is not increased. There is no need to store data and take a difference from the current detection value, and the detection process can be simplified accordingly.
If the detection sensor 35 of this modification is used in place of the detection sensor 6 of the above embodiment, it is not necessary to move the detection sensor in the above embodiment, so the drive motor 11 and the rail 13 need to be arranged. The configuration can be simplified.

(2) In the above embodiment, the detection sensor 6 includes the light emitting element 61 and the light receiving element 62. For example, a laser beam from the printer head 10 is used instead of the light beam emitted from the light emitting element 61. It is also possible to adopt a configuration in which residual toner is detected using light from the exposure means.
FIG. 9 is a diagram illustrating a configuration example in which residual toner detection is performed using light from an exposure unit instead of a light emitting element.

  As shown in the figure, in this configuration example, the folding mirror 2 is swingably held (the holding means is omitted), and the folding mirror 2 is moved to the first position (solid line) during image formation. The laser beam L from the printer head 10 is guided to the exposure position E. On the other hand, when the residual toner is detected, the folding mirror 2 is moved to the second position (dashed line position), the laser beam L is guided to the contact portion of the film 51 with the photosensitive drum 3, and the light receiving element 72 is moved in the main scanning direction. Reflected light from the film 51 is received by the light receiving element 72 while being moved.

  In the case of this configuration, the exposure means (printer head, folding mirror, etc.) also serves as the light emitting element, and the light emitting element becomes unnecessary. Further, when the residual toner is detected, a contact portion between the film 51 and the photosensitive drum 3 according to the movement of the light receiving element 72 so that the reflected light just reaches the moving light receiving element 72, for example. Even if it is emitted so that the irradiation position is partially changed (following the movement of the light receiving element 72), or the contact portion is emitted uniformly over the entire width in the main scanning direction. good.

For example, in a configuration using a linear array in which a large number of light emitters such as LEDs are arranged in a row as the exposure unit, the linear array itself can be swung.
(3) Although the reflection type optical sensor is used as the detection sensor 6, for example, a transmission type may be used. In the case of this configuration, the light emitting element and the light receiving element are arranged at positions facing each other with the film 51 interposed therebetween. The most suitable one is selected depending on the collection member in the apparatus, the layout of other members, and the like.

  (4) In the above embodiment, the film 51 is attached to the charging charger 5. However, the arrangement position may be a position other than the position from the development position to the transfer position in the rotation direction of the photosensitive drum 3. It ’s fine. Preferably, the distance from the cleaning position (the position where the surface of the photosensitive drum 3 is cleaned by the cleaning blade 41) to the development position is good, and particularly from the cleaning position to the exposure position E is desirable.

  (5) In the above embodiment, in the residual toner detection process, when the detection value ≧ the predetermined value T (“YES” in step S4), a message indicating that it is time to replace the cleaning blade 41 is displayed. (Step S12) For example, it is possible to display a message indicating that the replacement time has not yet reached but the time is near. A value (predetermined value t <T) that is assumed to cause image quality deterioration due to enlargement of the chipping of the cleaning blade 41 is derived in advance from experiments and the replacement time is near when the detected value is equal to or greater than the predetermined value t. A message to that effect may be displayed. In addition to displaying a message, it is also possible to notify the user by displaying a lamp or the like indicating that the replacement time or replacement time is near. In this sense, the control unit 1, the display unit 12, and the like function as display means. Furthermore, it may be notified by voice.

(6) In the above embodiment, an example in which the image forming apparatus of the present invention is applied to a printer has been described. However, the present invention is not limited to this. For example, the present invention can be applied to a copying machine, FAX, MFP (Multiple Function Peripheral), and the like.
In the above embodiment, an example in which the photosensitive drum is an image carrier has been described. However, the present invention is not limited to this. For example, a toner image formed on the photosensitive drum is temporarily transferred to an intermediate transfer member (so-called intermediate transfer member). The intermediate transfer member in an image forming apparatus that forms an image by transferring the toner image transferred to the transfer member such as a recording sheet to a transfer material such as a recording sheet. You can also In this case, a cleaner that cleans the surface of the intermediate transfer body (toner image transfer surface) using a cleaning member such as a cleaning blade, and residual toner on the intermediate transfer body that has contacted the surface of the intermediate transfer body and passed through the cleaning member A film, a blade, and the like for collecting the particles are arranged as a collecting member.

  By detecting the chipping of the cleaning member at an early stage, the present invention can be used for an image forming apparatus that is required to suppress the progress of the chipping expansion and to suppress image quality deterioration due to poor cleaning.

FIG. 2 is a diagram illustrating a schematic configuration of the entire printer. It is the figure which expanded and showed the film 51 distribute | arranged to a printer, and its periphery. It is a side view when the film 51 is seen from the arrow B direction of FIG. 2 is a block diagram illustrating a configuration of a control unit 1. FIG. 4 is a flowchart showing the content of residual toner detection processing executed by a CPU. 4 is a graph illustrating an example of a voltage waveform of a detection value at each position of a film 51. FIG. 3 is a perspective view of a state where a toner pattern is formed on a photosensitive drum 3 when viewed from the direction of arrow C in FIG. 2. It is a figure which shows the structural example in the case of detecting a toner using a web. FIG. 6 is a diagram illustrating a configuration example when residual toner detection is performed using light from an exposure unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control part 2 Folding mirror 3 Photosensitive drum 4 Cleaner 5 Charging charger 6, 36 Detection sensor 7 Developer 10 Printer head 12 Display part 13 Rail 30 Detection part 33 Web-like member 41 Cleaning blade 51 Film 61 Light emitting element 62, 72 Light receiving element

Claims (15)

An image forming apparatus that forms an image by transferring a developer image formed on an image carrier to a transfer material,
A cleaning member for cleaning the surface of the image carrier after transfer;
A collecting means having a collecting member that contacts the surface of the image carrier and collects the developer remaining on the image carrier without being cleaned by the cleaning member;
Detecting means for detecting the developer collected by the collecting member;
An image forming apparatus comprising:   When the value of the detection signal from the detection means indicates that the amount of the collected developer exceeds the first predetermined amount, between the cleaning member and the surface of the image carrier. The image forming apparatus according to claim 1, further comprising developer supplying means for supplying the developer to the image forming apparatus.   The image forming apparatus according to claim 1, wherein the detection unit detects the developer when a predetermined time is reached.   The image forming apparatus according to claim 3, wherein the predetermined time is when the number of times of image formation reaches a predetermined number.   The image forming apparatus according to claim 3, wherein the predetermined time is when a predetermined time elapses after the image forming operation is started.   If the value of the detection signal from the detection means indicates that the amount of collected developer exceeds the second predetermined amount, it is time to replace the cleaning member or replace it. The image forming apparatus according to claim 1, further comprising a notification unit that notifies the user that the time is near.   The image forming apparatus according to claim 6, wherein the notification unit is a display unit, and notifies the user that the replacement time or the replacement time is near.   The length of the contact portion of the collecting member with the image carrier is equal to or greater than the cleaning width of the surface of the image carrier by the cleaning member. Image forming apparatus. The detection means includes
A detection sensor;
Moving means for moving the detection sensor along a contact portion of the collecting member with the surface of the image carrier,
The image forming apparatus according to claim 8, wherein the developer collected by the collecting member is detected while moving the detection sensor along the contact portion. The collecting member is made of a translucent member,
The detection means includes
A light emitting element and a light receiving element,
A developer is detected by irradiating a light beam emitted from the light emitting element to a contact portion of the collecting member with the image carrier and receiving the reflected light or transmitted light by the light receiving element. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. Exposure means for exposing the surface of the image carrier to form a latent image on the surface of the image carrier;
Developing means for developing a latent image on the surface of the image carrier to form a developer image,
The exposure means also serves as the light emitting element,
The light beam emission direction is configured to be switchable between a first direction toward the exposure position on the image carrier and a second direction toward the contact portion of the collection member with the image carrier. The image forming apparatus according to claim 10. The collecting member is a film-like or blade-like member whose tip portion contacts the surface of the image carrier and stops and accumulates the developer remaining on the image carrier in the contact portion,
12. The image according to claim 1, wherein the detection unit detects developer accumulated in a contact portion of the film-like or blade-like member with the image carrier. Forming equipment. The collecting member is a web-shaped member,
The collecting means includes a supply roller that supplies the web-shaped member, and a winding roller that winds the web-shaped member, and is between the supply roller and the winding roller in the web-shaped member. Is contacted with the surface of the image carrier, and the developer is stopped and adhered to the contact portion.
12. The developer according to claim 1, wherein the detection unit detects a developer attached to a contact portion of the web-shaped member wound up by the winding roller with the image carrier. The image forming apparatus according to claim 1. The cleaning member is a cleaning blade whose tip portion contacts the surface of the image carrier and cleans the image carrier surface,
The image forming apparatus according to claim 1, wherein the image carrier is formed in a drum shape or a belt shape. The image carrier is a rotating body,
The collecting member is
In the rotation direction of the image carrier, the image carrier surface is disposed between a cleaning position where the surface of the image carrier is cleaned by the cleaning member and a development position where a developer image is formed on the image carrier by development. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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