JP2011007971A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus, which does not require troublesome work to periodically exchange lubricant and which avoids upsizing of the apparatus by adopting a method for supplying the lubricant through toner.SOLUTION: The image forming apparatus 10 using the toner, to which the lubricant is added, includes a developing device 44 which forms a toner image and applies the lubricant through the toner, a photoreceptor drum 41 on which the toner image is formed and to which the lubricant is applied, a transfer belt 45 which transfers the formed toner image to paper P, a cleaning device 47 which removes toner remaining on the photoreceptor drum 41, and a control part 1. When a power source of the image forming apparatus 10 is switched from OFF to ON, the control part 1 shifts a mode to a lubricant applying mode, and performs control so as to form the toner image having 0.2 mm to 1.5 mm length in a vertical scanning direction on the photoreceptor drum 41 in such a state that the photoreceptor drum 41 and the transfer belt 45 are physically separated from each other.

Description

  The present invention relates to an image forming apparatus.

  Lubricant is applied to the surface of the photosensitive drum constituting the image forming apparatus. The lubricant plays a role of weakening the physical adhesion between the toner and the photosensitive drum to make it easier for the cleaning device to remove the toner and improving the transferability of the toner.

There are the following two methods for supplying the lubricant onto the photosensitive drum.
(1) A method of supplying a solid or powder lubricant with a brush or the like.
(2) A method of supplying via a toner to which a lubricant is added.

  As conventional techniques, for example, Patent Documents 1 to 3 disclose a method of (1) above, and Patent Document 4 discloses a method of supplying a lubricant using the method (2) above.

  According to Patent Document 1, at least when the lubricant supply unit is newly replaced, the rotation speed of the brush is lowered by a preliminary rotation operation of the image carrier at the start of image formation for a certain number of sheets, and the image carrier is moved to the image carrier. A technique for regulating the amount of lubricant supplied is disclosed (see Patent Document 1).

  Patent Document 2 discloses a technique for supplying a lubricant and toner that adsorbs the lubricant to the surface of the image carrier after the process cartridge is replaced with a new one and before the image forming operation is started. (See Patent Document 2).

  Further, according to Patent Document 3, when the photoconductor new article detecting means of the image forming apparatus main body detects that the photoconductor is new, the lubricant is applied by a brush, the photoconductor torque is measured, and the application operation time is calculated. A technique for deciding is disclosed (see Patent Document 3).

  Patent Document 4 discloses a technique for supplying a lubricant onto a photosensitive drum by using a developing device containing a lubricant, attaching the developer to an image carrier separately from the purpose of development. (See Patent Document 4).

JP 2001-331063 A JP 2001-343861 A JP 2005-181742 A JP 2003-241570 A

  However, the techniques of Patent Documents 1 to 3 all require periodic replacement of the lubricant and are complicated. Further, since parts and members for supplying the lubricant are incorporated in the image forming apparatus, there arises a problem that the apparatus becomes large.

  Further, in the technique of Patent Document 4, productivity may be lowered because the timing of supplying the lubricant is at the end of the job or during the job. Further, a large amount of toner is deposited on the photoreceptor drum to supply the lubricant. As a result, there is a case where the lubricant on the photosensitive drum is scraped off by a large amount of toner accumulated at the contact portion between the cleaning device (for example, blade) and the photosensitive drum, resulting in poor cleaning.

  An object of the present invention is to employ a method of supplying a lubricant through toner, thereby eliminating the complicated work of periodically replacing the lubricant, avoiding the enlargement of the apparatus, and further maintaining the productivity. An object of the present invention is to provide an image forming apparatus capable of preventing defective cleaning.

According to the present invention,
In an image forming apparatus using toner to which a lubricant is added,
A developing device for forming a toner image;
A photosensitive drum on which the toner image is formed;
A transfer belt for transferring the formed toner image to paper;
A cleaning device that removes toner remaining on the photosensitive drum without being transferred to the paper, and applying the lubricant added to the toner onto the photosensitive drum;
A control unit,
The control unit shifts to the lubricant application mode when the power of the image forming apparatus is switched from OFF to ON, and the photosensitive drum and the transfer belt are physically separated in the lubricant application mode. Thus, there is provided an image forming apparatus that controls to form a toner image having a length in the sub-scanning direction of 0.2 mm to 1.5 mm on the photosensitive drum.

According to the present invention, by adopting a method of supplying a lubricant via toner, a complicated operation for periodically replacing the lubricant is not required, and an increase in the size of the apparatus can be avoided.
Also, productivity is maintained by executing the lubricant application mode at a predetermined timing, and the length of the toner black belt in the sub-scanning direction is set to an appropriate range (0.2 mm to 1.5 mm). In this way, it is possible to prevent blade turning and cleaning failure.

1 is an overall configuration diagram of an image forming apparatus. It is a figure which shows an example of a toner black belt. 1 is an overall configuration diagram of an image forming unit. It is a figure which shows the relationship between a contact angle and lubricant amount. It is a conceptual diagram of a contact angle. It is a flowchart which shows the lubricant application process in lubricant application mode. It is a figure which shows the relationship between a photoreceptor rotation time and a contact angle. It is a figure which shows the relationship between a photoreceptor rotation time and a contact angle. It is a figure which shows a timing chart. It is a figure which shows experimental conditions and an evaluation item.

  The configuration and operation of the image forming apparatus in this embodiment will be described in detail with reference to the drawings. In addition, this embodiment is an example and this invention is not limited to this.

FIG. 1 is a schematic configuration diagram of the image forming apparatus 10.
The image forming apparatus 10 includes an automatic document feeder 20, a scanner unit 30, an image forming unit 40, and a paper feeding unit 50.

The automatic document conveyance unit 20 conveys the document D placed on the document placement tray one by one to a predetermined conveyance path.
The scanner unit 30 irradiates the conveyed document D with a light source and receives reflected light reflected from the document D. The scanner unit 30 converts the received optical signal into an electrical signal (image data), and outputs the converted image data to the image forming unit 40.

  The image forming unit 40 forms a toner image on the photosensitive drum 41 based on the image data, and performs a series of image forming processes until the formed toner image is transferred to the paper P and fixed.

  In addition, when the image forming unit 40 continuously forms image data on a plurality of sheets P, a toner image for forced toner discharge (hereinafter, “toner black belt”) is applied to the non-image area of the photosensitive drum 41. It is formed on the photosensitive drum 41. Note that the non-image area generally means “inter-sheet space” that is an area between sheets. By forming a black toner band in a non-image area (between sheets) during image formation, a reduction in productivity is prevented.

FIG. 2 shows an example of the toner black belt.
As shown in FIG. 2, the toner black belt TK is a belt-like toner image composed of only black pixels and extending in the main scanning direction (axial direction of the photosensitive drum 41).
The toner black belt TK is formed in a non-image area (between sheets) between the toner images transferred to the sheets P1 and P2.

  The toner black belt TK shown in FIG. 2 is composed of only black pixels. However, the present invention is not limited to this. For example, the toner black belt TK is composed of black pixels and white pixels so as to form vertical stripes, horizontal stripes, diagonal stripes, or grids. It may be done.

  In this embodiment, since the monochrome image forming apparatus is described as an example, the toner black belt TK is composed of black pixels (or white pixels), but in the case of a color image forming apparatus. It is not limited to this. In the case of a color image forming apparatus, the toner image for forced toner discharge corresponding to the toner black belt TK is composed of pixels (colored pixels) or white pixels for each color with respect to the photosensitive drum for each color. Become.

Returning to FIG. 1, the image forming unit 40 includes a fixing heating roller 401 and a temperature sensor 401a.
The fixing heating roller 401 fixes the toner image on the paper P by sandwiching the paper P between the rollers and applying heat and pressure.
The temperature sensor 401 a detects the temperature of the fixing heating roller 401 and outputs information on the detected temperature to the control unit 1.

  The paper feeding unit 50 stores a plurality of types of paper P in a tray, and feeds the paper P to the image forming unit 40 via a predetermined conveyance path.

  The control unit 1 comprehensively controls the operation of each unit (20 to 50) of the image forming apparatus 10 described above. Particularly in the present embodiment, the control of the image forming unit 40 performed by the control unit 1 will be described later.

FIG. 3 shows the overall configuration of the image forming unit 40.
The image forming unit 40 includes a charging device 42, an exposure device 43, a developing device 44, a transfer belt 45, a separation claw 46, a cleaning device 47, an IDC sensor 48, and the like around a drum-shaped photosensitive drum 41. The In FIG. 3, the illustration of the fixing heating roller 401 is omitted.

  Note that the image forming unit 40 may be configured such that one unit configured by removing the exposure device 43 and the fixing heating roller 401 from the components of the image forming unit 40 is an image forming unit and can be replaced independently.

The charging device 42 uniformly charges the surface of the photosensitive drum 41.
The exposure device 43 exposes a non-image area (excluding the toner black belt area) of the photosensitive drum 41, and forms an electrostatic latent image in the image area by removing the charge of the exposed portion.

  The developing device 44 includes a developing roller 441, a stirring roller 442, a supply roller 443, and the like. The developing device 44 develops the toner image by attaching toner to the electrostatic latent image on the photosensitive drum 41.

  A lubricant is added to the toner, and the developing device 44 supplies the lubricant onto the photosensitive drum 41 via the toner. For example, stearic acid zinc is used as the lubricant. By supplying the lubricant, the physical adhesion between the toner and the photosensitive drum 41 is weakened, and the cleaning device 47 can easily remove the toner.

  The transfer belt 45 applies a charge having a polarity opposite to that of the toner from the back surface of the paper P during image formation, and transfers the toner image attached to the photosensitive drum 41 to the paper P by electrostatic force. At the time of transfer, the transfer belt 45 is pressed against the photosensitive drum 41 with the paper P interposed therebetween.

The transfer belt 45 applies a charge having the same polarity as that of the toner in order to prevent the transfer belt 45 from being contaminated by the toner black belt during non-image formation. Therefore, during non-image formation where the transfer belt 45 is pressure-bonded to the photosensitive drum 41, the lubricant having the opposite polarity to the toner moves to the transfer belt 45 side.
The amount of lubricant on the photosensitive drum 41 can be grasped by measuring the contact angle.

The relationship between the contact angle and the amount of lubricant will be described with reference to FIGS. 4A and 4B.
The graph GPH1 shown in FIG. 4A shows the relationship between the measurement location and the contact angle. 5,000 originals composed of a solid black portion, a halftone portion, and a white background portion were printed, and then the contact angle of the lubricant on the photosensitive drum 41 was measured.

FIG. 4B shows a conceptual diagram of the contact angle.
For the measurement of the contact angle, for example, Kyowa Interface Chemical / Fully Automatic Contact Angle Meter CA-W is used.
The case where the contact angle is large indicates that the lubricant is sufficiently applied on the photosensitive drum 41. The case where the contact angle is small indicates that the lubricant is insufficient on the photosensitive drum 41.

  In an image having a large amount of toner supplied to the blade of the cleaning device 47, the contact angle becomes small because the lubricant is scraped off by the toner.

  Returning to FIG. 3, the separation claw 46 physically contacts the surface of the photosensitive drum 41 to separate the paper P and the photosensitive drum 41.

The cleaning device 47 removes residual toner adhering to the photosensitive drum 41 without being transferred to the paper P with a brush 471, a blade 472, or the like.
As long as the lubricant is sufficiently applied to the photosensitive drum 41, the cleaning device 47 can sufficiently remove even if there is a large amount of residual toner.

An IDC (Image Density Control) sensor 49 includes a light emitting element and a light receiving element, and is disposed opposite to the photosensitive drum 41.
The IDC sensor 49 irradiates the surface of the photosensitive drum 41 with infrared rays (irradiated light) by the light emitting element, and receives the reflected light reflected from the surface of the photosensitive drum 41 by the light receiving element.

The control unit 1 comprehensively controls the operation of each device of the image forming unit 40.
For example, the control unit 1 controls the exposure device 43 to form an electrostatic latent image to be printed or an electrostatic latent image for forced toner discharge. In addition, the control unit 1 controls the developing device 44 so as to develop a toner image or a toner black belt to be printed.

  Further, the control unit 1 performs control when supplying the lubricant to the photosensitive drum 41 in the “lubricant application mode”.

  The transition to the lubricant application mode is performed, for example, in the morning. “Morning” here means, for example, (1) that the power of the image forming apparatus has been switched from OFF to ON, (2) that a certain time has passed since the power was turned OFF, and (3) a fixing heating roller. A situation where the temperature of 401 is equal to or lower than a certain value is satisfied.

  In the morning printing process when a printing process with a low printing rate was performed on the previous day, the lubricant on the photoconductive drum 41 becomes insufficient, and image quality deterioration such as density unevenness due to defective cleaning or transfer may occur. .

  Further, as another example of shifting to the lubricant application mode, for example, in the operation unit 2, a mode pressing button may be pressed by the user.

  The operation unit 2 includes a touch panel on which various buttons are displayed. When the button is pressed by a user operation, the operation unit 2 generates an operation signal and outputs the generated operation signal to the control unit 1.

  The storage unit 3 includes a nonvolatile memory such as a ROM (Read Only Media), and stores a system program and various programs.

With reference to FIG. 5, the morning lubricant application process will be described.
The control unit 1 confirms that the image forming apparatus 10 is powered on (step S1).
The control unit 1 determines whether or not a predetermined time has elapsed since the previous power-off (step S2).

If the predetermined time has not elapsed (step S2; N), the control unit 1 determines that it is not in the morning and ends the morning lubricant application process.
When the predetermined time has elapsed (step S2; Y), the control unit 1 determines whether or not the temperature of the fixing heating roller 401 is equal to or lower than a predetermined value (step S3).

If it is not less than the predetermined value (step S3; N), the controller 1 determines that it is not in the morning and ends the morning lubricant application process.
When it is below a certain value (step S3; Y), the control unit 1 determines that it is one in the morning and shifts to the lubricant application mode (see steps S4 to S11).
Hereinafter, the processing in the lubricant application mode will be specifically described.

The control unit 1 sets the blade 472 at the crimping position (step S4).
The crimping position is a position where the blade 472 can remove the residual toner adhering to the photosensitive drum 41.

  The control unit 1 executes a normal process start-up sequence without separating the transfer belt 45 from the photosensitive drum 41 and setting the transfer belt 45 at the pressure-bonding position (step S5).

  According to the normal process startup sequence, the control unit 1 starts up the processes of the photosensitive drum 41, the developing roller 441, the stirring roller 442, the charging device 42, the charging grid, and the developing bias.

  The control unit 1 forms a black toner band of 316 mm in the main scanning direction (photosensitive drum axis direction) and 1.25 mm in the sub-scanning direction (paper transport direction) on the photosensitive drum 41 at intervals of 0.5 seconds ( Step S6).

FIG. 6 shows a relationship GPH2 between the photosensitive drum rotation time and the contact angle.
A graph G1 is a graph when the toner belt is formed by rotating the photosensitive drum 41 and the developing roller 441 without pressing the transfer belt 45 away from the photosensitive drum 41.

  Graph G2 is a graph when the transfer belt 45 is pressed against the photosensitive drum 41 and the photosensitive drum 41 and the developing roller 441 are rotated to form a black toner band.

  In both graphs G1 and G2, the length of the toner black belt in the main scanning direction is 316 mm, and the length in the sub-scanning direction is 1.5 mm.

  According to FIG. 6, the contact angle is smaller in the graph G <b> 2 in which the transfer belt 45 is pressure-bonded to the photosensitive drum 41. This indicates that the lubricant on the photosensitive drum 41 is insufficient in the graph G2.

The reason why the lubricant on the photosensitive drum 41 is insufficient as described above when the transfer belt 45 and the photosensitive drum 41 are pressure-bonded is as follows.
In the nip portion between the transfer belt 45 and the photosensitive drum 41, in order to prevent the transfer belt 45 from being contaminated by the toner black belt, a bias having the same polarity (−) as that of the negatively charged toner is used. Is applied to the transfer belt 45. Therefore, the lubricant charged positively (+) is attracted to the transfer belt 45 charged negatively (−).

  For the above reasons, when supplying the lubricant onto the photosensitive drum 41, it is desirable not to press the photosensitive drum 41 and the transfer belt 45 together.

  For example, when the contact angle at which cleaning failure occurs is 93 ° or less, according to the graph G1, the lubricant can be removed to such an extent that the cleaning failure can be eliminated by rotating the photosensitive drum 41 and the developing roller 441 for about 3 minutes. It is applied on the photosensitive drum 41.

The control unit 1 determines whether or not a certain time (for example, 3 minutes) has elapsed (step S7).
When the predetermined time has not elapsed (step S7; N), the control unit 1 continuously forms a toner black belt.

FIG. 7 shows a relationship GPH3 between the photosensitive drum rotation time and the contact angle.
Graphs G <b> 11 to G <b> 17 are graphs when a black toner band is formed by rotating the photosensitive drum 41 and the developing roller 441 without pressing the transfer belt 45 to the photosensitive drum 41.

  In the graphs G11 to G17, the length of the toner black belt in the main scanning direction is 316 mm, and the lengths in the sub scanning direction are different from each other.

  According to FIG. 7, in any of the graphs G11 to G17, the contact angle increases as the photosensitive drum 41 and the developing roller of the developing device 44 continue to rotate. That is, a large amount of lubricant is applied on the photosensitive drum 41.

  In the graphs G11 to G17, the contact angle is smaller as the length of the toner black belt in the sub-scanning direction is longer. That is, the amount of lubricant applied on the photosensitive drum 41 is small.

  For example, when the contact angle at which cleaning failure occurs is 93 ° or less, the cleaning failure occurs in the graphs G16 and G17. Graphs G16 and G17 are graphs when the length of the toner black belt in the sub-scanning direction is 3.5 mm or more.

  Similarly, when the contact angle at which cleaning failure occurs is 93 ° or less, no cleaning failure has occurred in the graphs G11 to G15. Graphs G11 to G15 are graphs when the length of the toner black belt in the sub-scanning direction is 0.2 mm to 3.0 mm.

  Here, when the length of the toner black belt in the sub-scanning direction is 0.1 mm or less, the amount of toner supplied to the blade 472 is insufficient in the photosensitive drum 41, and the blade is turned over. “Blade turning” refers to a state in which the blade is turned up and cannot properly remove toner. When blade turning occurs, the printing process is stopped and maintenance work is required. When the length of the toner black belt in the sub-scanning direction was 0.2 mm, no blade turning occurred.

Of the graphs G11 to G17 shown in FIG. 7, according to the graphs G11 to G15, neither cleaning failure nor blade turning occurs.
Among the graphs G11 to G15, from the viewpoint of reducing the toner consumption as much as possible, the graphs G11 to G14 in which the sub-scanning direction of the toner black belt is 0.2 mm to 1.5 mm are more preferable.

  Returning to FIG. 5, when the control unit 1 does not press the transfer belt 45 away from the photosensitive drum 41 and forms a black toner belt (step S7; Y), the control unit 1 A normal process shutdown sequence is executed (step S8).

  According to the normal process deactivation sequence, the control unit 1 deactivates the processes of the photosensitive drum 41, the developing roller 441 and the stirring roller 442, the charging device 42, the charging grid and the developing bias.

The control unit 1 sets the blade 472 at the fine pressure bonding position (step S9).
The controller 1 performs reflection adjustment of the photosensitive drum 41 by the IDC sensor 49, receives the amount of reflected light at the time of 4.5V output, and stores it by a storage medium (not shown) (step S10).

  The control unit 1 clears the counter of the photosensitive drum 41 (step S11), and ends the lubricant application process.

  The counter of the photoconductive drum 41 is counter information of the photoconductive drum 41 such as the number of prints printed by the photoconductive drum 41, the travel time, travel distance, rotational speed, and rotational time of the photoconductive drum 41.

FIG. 8 shows a timing chart.
The timing chart shown in FIG. 8 shows the timing in the processing of steps S4 to S9.

  Timings T1 to T4 are timings of a normal process start-up sequence, and are timings of the processes in steps S4 to S6.

The blade 472 is set from the fine pressure bonding position to the pressure bonding position immediately before shifting to the lubricant application mode (timing T1).
The photosensitive drum 41, the developing roller 441, and the stirring roller 442 are driven (timing T2).
At the same time as the timing T2, a toner black belt is formed (timing T3).
The charging device 42, the charging grid, and the developing bias are driven (timing T4).

  Timings T5 to T8 are timings of the normal process fall-down sequence, and are timings of the processing of steps S7 to S9.

The charging device 42, the charging grid, and the developing bias are stopped (timing T5).
The photosensitive drum 41, the developing roller 441, and the stirring roller 442 are stopped (timing T6).
At the same time as the timing T6, the formation of the toner black belt is completed (timing T7).
Finally, the blade 472 is set from the crimping position to the fine crimping position (timing T8).

FIG. 9 shows experimental conditions and evaluation items. Other experimental conditions are also shown.
An experiment for confirming the effectiveness of the lubricant application mode was performed under the experimental conditions shown in FIG.

  The experiment was performed by (1) implementation of a lubricant application mode or (2) implementation of a paper passing test. The lubricant application mode was performed in the same situation as in the morning. That is, the image forming apparatus 10 is switched from OFF to ON, a certain time has elapsed since the power was turned OFF, and the temperature of the fixing heating roller 401 is not more than a certain value. In addition, the paper passing test was performed by printing 100,000 sheets of a double-sided original with a printing rate of 0.3%.

After the experiment (1) or (2) was performed, the evaluation items shown in FIG. 9 were evaluated.
The evaluation items were an evaluation of visual turning of the blade and an evaluation of initial cleaning performance. Further, the initial cleaning performance was judged based on whether the image quality of the image formed on the paper in the paper passing test was good or bad.

  Moreover, evaluation in an evaluation item evaluated as (circle), (triangle | delta), and x. The criteria of ◯ and △ were judged based on whether or not blade turning or initial cleaning failure occurred.

  In the case of occurrence (Δ or ×), the criteria for Δ and × were Δ when the occurrence was minor, and × when the occurrence was serious.

In Example 1, in the lubricant application mode, the transfer belt 45 is not pressed away from the photosensitive drum 41 and the length of the toner black belt formed on the photosensitive drum 41 in the sub-scanning direction is 0.2 mm. The formation interval was 285 mm.
As a result, blade turning of the blade 472 did not occur, and no initial cleaning failure occurred. All evaluations were ◯.

In Example 2, in the lubricant application mode, the transfer belt 45 is not pressed away from the photosensitive drum 41, and the length of the black toner belt formed on the photosensitive drum 41 in the sub-scanning direction is 1.5 mm. The formation interval was 285 mm.
As a result, blade turning of the blade 472 did not occur, and no initial cleaning failure occurred. All evaluations were ◯.

In Example 3, in the lubricant application mode, the transfer belt 45 is not pressure-bonded away from the photosensitive drum 41, and the length of the toner black belt formed on the photosensitive drum 41 in the sub-scanning direction is 3.0 mm. The formation interval was 285 mm.
As a result, blade turning of the blade 472 did not occur, and no initial cleaning failure occurred. All evaluations were ◯.

In Comparative Example 1, in the lubricant application mode, the transfer belt 45 is pressure-bonded to the photosensitive drum 41, the length of the toner black belt formed on the photosensitive drum 41 in the sub-scanning direction is 3.0 mm, and the formation interval is Was 285 mm.
As a result, the blade 472 was not turned over, but an initial cleaning failure occurred. The evaluation for turning the blade was ◯, and the evaluation for initial cleaning was x.

In Comparative Example 2, in the lubricant application mode, the transfer belt 45 is not pressure-bonded away from the photosensitive drum 41, and the length of the toner black belt formed on the photosensitive drum 41 in the sub-scanning direction is 3.0 mm. The formation interval was 570 mm.
As a result, blade turning of the blade 472 occurred, and the evaluation was x. The initial cleaning performance could not be evaluated.

In Comparative Example 3, in the lubricant application mode, the transfer belt 45 is not pressure-bonded away from the photosensitive drum 41, and the length of the toner black belt formed on the photosensitive drum 41 in the sub-scanning direction is 0.1 mm. The formation interval was 285 mm.
As a result, blade turning of the blade 472 occurred, and the evaluation was x. The initial cleaning performance could not be evaluated.

In Comparative Example 4, in the lubricant application mode, the transfer belt 45 is not pressed away from the photosensitive drum 41 and the length of the toner black belt formed on the photosensitive drum 41 in the sub-scanning direction is 3.5 mm. The formation interval was 285 mm.
As a result, the blade 472 was not turned over, but an initial cleaning failure occurred. The evaluation for turning the blade was ◯, and the evaluation for initial cleaning was Δ.

In Comparative Example 5, the initial cleaning performance was evaluated without shifting to the lubricant application mode and without performing the morning lubricant application process (see FIG. 5).
As a result, an initial cleaning failure occurred and the evaluation was x.

  As described above, according to this embodiment, the length of the toner black belt in the sub-scanning direction is set to 0.2 mm to 1.5 mm, and the lubricant application mode is executed when the power is turned on in the morning to maintain productivity. In addition, blade turning and poor cleaning can be prevented. Since the method of applying via toner is employed, the troublesome work of periodically replacing the lubricant is not required, and the problem that the apparatus itself becomes large can be solved.

  In the “morning one”, (1) the power of the image forming apparatus is switched from OFF to ON, (2) a certain time has passed since the power was turned OFF, and (3) the temperature inside the image forming apparatus is constant. It can be determined as a situation that is less than or equal to the value.

  Further, the “temperature inside the image forming apparatus” in (3) can be determined by the temperature of the fixing heating roller 401.

  Further, by setting the interval between toner black belts to be 1 to 1.5 rotations of the photosensitive drum 41, blade turning and cleaning failure can be prevented. Since the method of applying via toner is employed, the troublesome work of periodically replacing the lubricant is not required, and the problem that the apparatus itself becomes large can be solved.

  Further, the toner black belt is composed of only black pixels and extends in the axial direction of the photosensitive drum 41. However, in the case of a color image forming apparatus, a single color of Y, M, C, K is used. It can be configured by only colored pixels and extending in the axial direction of the photosensitive drum 41.

  Further, although the toner black belt is composed of only black pixels, it is composed of black pixels and white pixels (colored pixels and white pixels of Y, M, C, and K in the case of color), and includes vertical stripes, horizontal stripes, and diagonal stripes. It may be configured to have a stripe or lattice shape. More lubricant can be applied onto the photosensitive drum 41.

  At the end of the lubricant application mode, information relating to the photosensitive drum 41 (number of printed sheets, travel time, travel distance, rotation speed, rotation time) can be reset.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 20 Automatic document conveyance part 30 Scanner part 40 Image forming part 41 Photosensitive drum 42 Charging apparatus 43 Exposure apparatus 44 Developing apparatus 45 Transfer belt 46 Separation claw 47 Cleaning apparatus 48 IDC sensor 50 Paper feed part 1 Control part 2 Operation Part 3 Storage part

Claims (7)

In an image forming apparatus using toner to which a lubricant is added,
A developing device for forming a toner image;
A photosensitive drum on which the toner image is formed;
A transfer belt for transferring the formed toner image to paper;
A cleaning device that removes toner remaining on the photosensitive drum without being transferred to the paper, and applying the lubricant added to the toner onto the photosensitive drum;
A control unit,
The control unit shifts to the lubricant application mode when the power of the image forming apparatus is switched from OFF to ON, and the photosensitive drum and the transfer belt are physically separated in the lubricant application mode. An image forming apparatus that controls to form a toner image having a length in the sub-scanning direction of 0.2 mm to 1.5 mm on the photosensitive drum.   The controller is configured to apply the lubricant application mode when the power of the image forming apparatus is switched from OFF to ON, a predetermined time has elapsed since the power was turned OFF, and the temperature inside the image forming apparatus is equal to or lower than a predetermined value. The image forming apparatus according to claim 1, which shifts to   The image forming apparatus according to claim 2, wherein the temperature inside the image forming apparatus is a temperature of a fixing heating roller.   In the lubricant application mode, the control unit physically separates the photosensitive drum and the transfer belt, and each time the photosensitive drum makes one to 1.5 rotations, the toner image is The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled to be formed on a photosensitive drum.   The image forming apparatus according to claim 1, wherein the toner image includes only a single colored pixel and extends in an axial direction of the photosensitive drum.   The toner image is composed of a single colored pixel and a white pixel so as to form a vertical stripe, a horizontal stripe, an oblique stripe, and a lattice, and extends in the axial direction of the photosensitive drum. The image forming apparatus according to any one of the above. A storage unit that stores any or all of the number of prints by the photosensitive drum, the traveling time of the photosensitive drum, the traveling distance, the rotation number, and the rotation time;
The image forming apparatus according to claim 1, wherein the control unit resets information stored in the storage unit after finishing the control in the lubricant application mode.

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