JP2022144641A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can grasp the amount of wear of spacing members different for every apparatus and can appropriately perform correction of an image forming condition for every apparatus.SOLUTION: An image forming apparatus comprises: a photoreceptor drum 21; a developing unit 30; a pressure mechanism 13; and a control unit. The developing unit 30 includes a developing roller 34, spacing members 36, and a cleaning member 37. The spacing members 36 are supported at both ends of the developing roller 34 and hold the constant interval between the photoreceptor drum 21 and the developing roller 34. The control unit calculates the amount of wear of the spacing members 36 based on information representing the relationship between a rotation load force of the spacing members 36 measured before the start of usage of the image forming apparatus and a wear rate being the amount of wear of the spacing members 36 per unit drive time of the developing unit 30 and the cumulative driving time of the developing unit 30, and when the calculated wear amount reaches a predetermined threshold, executes image forming condition correction processing of correcting an image forming condition.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image forming apparatus.

2. Description of the Related Art In electrophotographic image forming apparatuses such as copiers and printers, it is sometimes necessary to maintain a constant distance between an image carrier such as a photosensitive drum and a toner carrier such as a developing roller. For this reason, an image forming apparatus is known in which a spacing member that contacts the surface of the photosensitive drum is provided at both ends of the rotating shaft of the developing roller. An example of conventional technology related to this is disclosed in Patent Document 1.

A conventional image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 2002-200000 includes a spacing member that maintains a distance between an image carrier and a developer carrier (toner carrier) by coming into contact with the image carrier, and an image carrier. and a controller for controlling the potential difference between the non-image portion potential and the developing bias. This image forming apparatus reduces the potential difference as the integrated value of the driving amount of the developer bearing member increases. As a result, it is possible to suppress the problem caused by the retention of the developer in the vicinity of the opposing portion between the developing sleeve and the photosensitive drum, which is caused by scraping of the spacing member along with the driving of the developer carrying member.

JP 2012-98629 A

However, in the prior art, the amount of wear of the spacing member is predicted from the driving time of the developer bearing member, but the amount of wear differs for each image forming apparatus, so it cannot be handled individually for each apparatus. I had a problem. As a result, it is not possible to appropriately correct image forming conditions for each apparatus, and there is concern that developer consumption will increase and image quality will deteriorate.

SUMMARY OF THE INVENTION The present invention has been devised in view of the above points, and is an image forming apparatus capable of grasping the amount of wear of a spacing member, which differs from apparatus to apparatus, and suitably correcting image forming conditions for each apparatus. The purpose is to provide an apparatus.

In order to solve the above problems, the image forming apparatus of the present invention includes an image carrier, a charging section, an exposure section, a development section, a voltage application section, a pressure mechanism, and a control section. The image carrier has a photosensitive layer on its surface. The charging section charges the surface of the image carrier. The exposure section forms an electrostatic latent image on the surface of the image carrier charged by the charging section. The developing section supplies toner to the surface of the image carrier and develops the electrostatic latent image to form a toner image. The voltage applying section applies a voltage to the charging section and the developing section. The pressurizing mechanism brings the developing section into contact with the image carrier and pressurizes it. The control section controls operations of the image carrier, the charging section, the exposure section, the development section, and the voltage application section. The developing section includes a toner carrier, a spacing member, and a cleaning member. The toner carrier is arranged to face the image carrier and carries the toner to be supplied to the surface of the image carrier. The spacing member is rotatably supported by both ends of the rotating shaft of the toner carrier, and is in contact with the surface of the image carrier to keep a constant spacing between the image carrier and the toner carrier. . The cleaning member contacts the surface of the spacing member to clean the surface of the spacing member. The control section determines the relationship between the rotational load force of the spacing member measured before the start of use of the image forming apparatus and the wear rate, which is the amount of wear of the spacing member per unit driving time of the developing section. Image forming conditions for calculating the amount of wear of the spacing member based on the information represented and the accumulated driving time of the developing unit, and correcting the image forming conditions when the calculated amount of wear reaches a predetermined threshold value Execute correction processing.

According to the configuration of the present invention, the wear of the interval holding member differs for each image forming apparatus based on the rotation load force of the interval holding member, the wear rate of the interval holding member, and the accumulated driving time of the developing unit. You can grasp the quantity. Then, based on the threshold for the amount of wear, it is possible to appropriately correct the image forming conditions for each apparatus.

1 is a schematic cross-sectional side view of an image forming apparatus according to one embodiment of the present invention; FIG. 2 is a block diagram showing the configuration of the image forming apparatus of FIG. 1; FIG. 2 is a cross-sectional side view of the periphery of an image forming unit of the image forming apparatus of FIG. 1; FIG. 4 is a cross-sectional plan view of a developing section of the image forming section of FIG. 3; FIG. FIG. 4 is an explanatory view showing a method of measuring a rotational load force at a contact portion between a photoreceptor drum and a spacing member of the image forming section of FIG. 3; 6 is a graph showing measurement results of the rotational load force of the spacing member by the method of FIG. 5; It is a graph which shows the relationship between the rotational load force and wear rate of a spacing member. 7 is a graph showing the relationship between the amount of wear of the spacing member and the rate of change in toner consumption; 5 is a graph showing changes in the rate of change in toner consumption in image forming apparatuses of Examples and Comparative Examples.

Embodiments of the present invention will be described below with reference to the drawings. In addition, this invention is not limited to the following contents.

FIG. 1 is a schematic cross-sectional side view showing the configuration of an image forming apparatus 1 according to an embodiment. FIG. 2 is a block diagram showing the configuration of the image forming apparatus 1 of FIG. 1. As shown in FIG. FIG. 3 is a cross-sectional side view of the periphery of the image forming unit 20 of the image forming apparatus 1 of FIG. An example of the image forming apparatus 1 of the present embodiment is a so-called printer that receives image data and a print command relating to a print job from an external computer and performs an image forming operation on a recording medium such as paper.

As shown in FIGS. 1, 2, and 3, the image forming apparatus 1 includes a paper feeding unit 3, a paper conveying unit 4, an exposure unit 5, an image forming unit 20, a transfer unit 7, and A fixing unit 8 , a paper ejection unit 9 , a control unit 10 and a storage unit 11 are provided.

The main body 2 has an operation panel 2C arranged on the front upper portion. The operation panel 2C has a display section 2D. The operation panel 2C displays on the display unit 2D a screen image related to setting of printing conditions such as the type and size of paper to be used, enlargement/reduction, single-sided printing, double-sided printing, and combined printing, and input of execution commands. , which accepts its input directly from the user himself. Further, the display unit 2D displays information related to image formation by the image forming apparatus 1. FIG.

The paper feeding unit 3 is arranged at the bottom of the main body 2 . The paper feeding unit 3 accommodates a plurality of sheets S, and separates and feeds out the sheets S one by one during printing. The paper conveying unit 4 conveys the paper S fed from the paper feeding unit 3 to the transfer unit 7 and the fixing unit 8, and further discharges the paper S after fixing to the paper discharging unit 9 from the paper discharging port 4a. The exposure unit 5 irradiates the image forming unit 20 with laser light L controlled based on image data.

The image forming section 20 is arranged above the paper feeding section 3 and downstream of the paper feeding section 3 in the paper transport direction. The image forming unit 20 includes a photosensitive drum (image carrier) 21 rotatably supported in a predetermined direction (counterclockwise in FIG. 2), as shown in FIG. The image forming section 20 further includes a charging section 22 , a developing section 30 , and a cleaning section 23 arranged around the photosensitive drum 21 along the direction of rotation thereof. A transfer section 7 is arranged between the developing section 30 and the cleaning section 23 .

The photosensitive drum 21 has a photosensitive layer 21a on its surface. The charging unit 22 has, for example, a charging roller 221 that is arranged to face and contact the photosensitive drum 21 . The charging section 22 charges the surface of the photosensitive drum 21 to a predetermined potential. The exposure unit 5 exposes the surface of the photosensitive drum 21 charged by the charging unit 22 to form an electrostatic latent image of the document image on the surface of the photosensitive drum 21 . The developing section 30 has, for example, a developing roller (toner carrier) 34 arranged to face the photosensitive drum 21 . The developing unit 30 supplies toner to the surface of the photosensitive drum 21 and develops the electrostatic latent image to form a toner image.

The transfer section 7 is arranged above the paper feeding section 3 and below the image forming section 20 . The transfer unit 7 has a transfer roller 71 that is arranged to face and contact the photosensitive drum 21 . The transfer unit 7 transfers the toner image formed on the surface of the photoreceptor drum 21 onto the sheet S. As shown in FIG. After the toner image is transferred onto the sheet S, the cleaning unit 23 cleans the surface of the photosensitive drum 21 by removing residual toner and the like.

The fixing section 8 is arranged above the paper feeding section 3 and downstream of the transfer section 7 in the paper conveying direction. The fixing section 8 heats and presses the sheet S onto which the toner image has been transferred, thereby fixing the toner image onto the sheet S. As shown in FIG.

The control unit 10 includes a CPU, an image processing unit, and other electronic circuits and electronic components (all not shown). The CPU controls the operation of each component provided in the image forming apparatus 1 based on control programs and data stored in the storage unit 11 to perform processing related to the functions of the image forming apparatus 1 . The paper feeding unit 3, the paper conveying unit 4, the exposure unit 5, the image forming unit 20, the transfer unit 7, and the fixing unit 8 receive commands individually from the control unit 10, and form images on the paper S in conjunction with each other. I do.

The storage unit 11 is configured by a combination of a non-volatile storage device such as a program ROM (Read Only Memory) and a data ROM (not shown) and a volatile storage device such as a RAM (Random Access Memory).

The image forming apparatus 1 further includes a voltage application section 12 and a pressure mechanism 13, as shown in FIGS.

The voltage application unit 12 includes, for example, a power supply unit and a control circuit (both not shown). The voltage applying section 12 is electrically connected to the charging roller 221 of the charging section 22 , the developing roller 34 of the developing section 30 , and the transfer roller 71 of the transfer section 7 . The voltage applying section 12 applies voltage to the charging roller 221 , developing roller 34 and transfer roller 71 . The control unit 10 controls the timing, voltage value, polarity, application time, and the like of voltage application to the charging roller 221 , the developing roller 34 , and the transfer roller 71 via the voltage application unit 12 .

The pressure mechanism 13 is arranged at a position separated from the photosensitive drum 21 with the developing unit 30 interposed therebetween. The pressurizing mechanisms 13 are arranged at both ends in the longitudinal direction of the developing section 30 (see FIG. 4). The pressure mechanism 13 has a pressure member 131 made of an elastic member such as a compression spring. One end of the pressure member 131 is connected to, for example, the frame 2F of the main body 2, and the other end is connected to a developing container 31 of the developing unit 30, which will be described later. , extending away from each other. The pressing mechanism 13 brings the developing unit 30 into contact with the photosensitive drum 21 and presses it.

Next, the configuration of the image forming section 20 will be described using FIG. 4 in addition to FIG. FIG. 4 is a cross-sectional plan view of the developing section 30 of the image forming section 20 of FIG. In FIG. 4, the transport path and transport direction of the developer in the developer container 31 are indicated by white arrows.

The photosensitive drum 21 has a cylindrical shape that is rotatably supported with its center axis horizontal, and is rotated around the center axis at a constant speed. The photoreceptor drum 21 has a photoreceptor layer 21a made of an inorganic photoreceptor such as amorphous silicon on the surface (peripheral surface) of a drum tube made of metal such as aluminum. An electrostatic latent image is formed on the surface of the photosensitive drum 21 .

The charging roller 221 extends parallel to the axial direction of the photosensitive drum 21 and is rotatably supported with its central axis horizontal. The charging roller 221 contacts the surface of the photoreceptor drum 21 and rotates as the photoreceptor drum 21 rotates. The charging roller 221 has, for example, a conductive layer on the surface (outer peripheral surface) of the core bar, which is made of crosslinked rubber or the like mixed with an ionic conductive material. When a predetermined charging voltage is applied to the charging roller 221, the surface of the photosensitive drum 21 is uniformly charged. The charging section 22 may have a structure having a corona discharge type corona wire instead of the charging roller 221 .

The developing unit 30 is detachable from the main body 2, for example. As shown in FIGS. 3 and 4, the developing section 30 includes a developer container 31, a first stirring and conveying member 32, a second stirring and conveying member 33, a developing roller (toner carrier) 34, and a regulating member 35. , a spacing member 36 and a cleaning member 37 .

The developer container 31 has an elongated shape extending along the axial direction of the photosensitive drum 21 (the depth direction in FIG. 3, the left and right direction in FIG. 4), and is arranged with its longitudinal direction horizontal. The developer container 31 contains, as developer to be supplied from the developing unit 30 to the photosensitive drum 21 , a magnetic one-component developer made only of magnetic toner, for example. The developer may be, for example, a non-magnetic one-component developer or a two-component developer containing toner and magnetic carrier. In addition, in the description within this document, the developer may be simply referred to as "toner".

The first agitating and conveying member 32 and the second agitating and conveying member 33 are arranged side by side in a first agitating chamber 312 and a second agitating chamber 313 separated by a partition portion 311 inside the developer container 31 . The first agitating/conveying member 32 and the second agitating/conveying member 33 are supported by the developer container 31 so as to be rotatable around an axis extending parallel to the photosensitive drum 21 . By rotating about their axes, the first stirring and conveying member 32 and the second stirring and conveying member 33 move the developer in mutually opposite directions (first direction w1 and second direction w2) along the axial direction of the rotation. is conveyed while stirring.

A part of the surface of the developing roller 34 is exposed from the developer container 31 and is arranged to face the photosensitive drum 21 . The developing roller 34 is rotatably supported by the developing container 31 about an axis extending parallel to the axis of the photosensitive drum 21 . Developing roller 34 carries toner to be supplied to the surface of photoreceptor drum 21 in a region facing photoreceptor drum 21 . The developing roller 34 supplies the toner in the developing container 31 to the surface of the photosensitive drum 21 and develops the electrostatic latent image to form a toner image.

The regulating member 35 is arranged on the upstream side in the rotation direction of the developing roller 34 in the area where the developing roller 34 and the photosensitive drum 21 face each other. The regulating member 35 faces and is close to the developing roller 34 and is arranged with a predetermined gap between its tip and the surface of the developing roller 34 . The regulating member 35 extends over the entire area of the developing roller 34 in the axial direction.

The toner in the developing container 31 is agitated and circulated by the first agitating and conveying member 32 and the second agitating and conveying member 33 , charged, and carried on the surface of the developing roller 34 . The layer thickness of the developer (toner) carried on the surface of the developing roller 34 is regulated by the regulating member 35 . When a predetermined development voltage is applied to the developing roller 34 , the potential difference between the potential of the surface of the photosensitive drum 21 causes the toner carried on the surface of the developing roller 34 to be exposed in the area facing the photosensitive drum 21 . It flies to the surface of body drum 21 . In this manner, the electrostatic latent image on the surface of photoreceptor drum 21 is developed with toner.

The spacing member 36 is rotatably supported at both ends of the rotating shaft 34x of the developing roller 34. As shown in FIG. The spacing member 36 is a cylindrical rotor made of, for example, POM (polyacetal) resin, and has a rotation axis coaxial with the rotation shaft 34x. The spacing member 36 has a diameter obtained by adding, for example, the diameter of the developing roller 34 to twice the length of the spacing desired to be maintained between the photosensitive drum 21 and the developing roller 34 .

When the developing unit 30 contacts and pressurizes the photosensitive drum 21 by the pressing mechanism 13 , the spacing member 36 comes into contact with the surface of the photosensitive drum 21 and maintains the gap between the photosensitive drum 21 and the developing roller 34 . is held constant. The spacing member 36 is driven by the photosensitive drum 21 due to the frictional force generated with the photosensitive drum 21 and rotates in the direction opposite to the photosensitive drum 21 .

The cleaning member 37 is arranged on the inner surface of the developer container 31 so as to face the spacing member 36 . The cleaning member 37 is a member in which a pile made of nylon or the like is flocked to an elastic member. The cleaning member 37 is attached to the inner surface of the developer container 31 with, for example, double-sided tape or the like, and extends along the peripheral surface of the interval holding member 36 .

The cleaning member 37 contacts the surface (peripheral surface) of the spacing member 36 . The cleaning member 37 has an elastic member compressed by a specified amount and a flocked portion pressed against the spacing member 36 to clean the surface (peripheral surface) of the spacing member 36 . As a result, the toner-containing developer, paper dust, etc. adhering to the surface of the spacing member 36 are removed.

Then, the control unit 10 of the image forming apparatus 1 of the present embodiment executes image forming condition correction processing for correcting the image forming conditions when the wear amount of the spacing member 36 reaches a predetermined threshold value.

In the image forming apparatus 1, the rotation load force of the interval holding member 36 is measured before the image forming apparatus 1 is started to be used, prior to the image forming condition correction processing related to the wear of the interval holding member 36. FIG. FIG. 5 is an explanatory view showing a method of measuring the rotational load force of the contact portion between the photoreceptor drum 21 and the spacing member 36 of the image forming section 20 of FIG. FIG. 6 is a graph showing the measurement results of the rotational load force of the spacing member 36 by the method of FIG.

The rotational load force of the spacing member 36 is measured and recorded before the image forming apparatus 1 is started to be used, that is, when the image forming apparatus 1 is manufactured. can be properly grasped. The rotational load force of the spacing member 36 is a force that prevents the cleaning member 37 from rotating the spacing member 36 , and is proportional to the pressure applied by the pressing mechanism 13 .

It is difficult to directly measure the rotational load force of the spacing member 36 while the photosensitive drum 21 and developing roller 34 are being driven. Therefore, the rotational load force of the spacing member 36 was indirectly defined by measuring the tensile force of the film passing through the nip portion between the photoreceptor drum 21 and the spacing member 36 . This tensile force is measured at two contact points between the photosensitive drum 21 and the spacing members 36 arranged at both ends of the rotating shaft 34x of the developing roller 34, that is, at two points.

As shown in FIG. 5, a PET (polyethylene terephthalate) film 50 having a width of 20 mm and a thickness of 50 μm, for example, is sandwiched in the nip portion N between the photosensitive drum 21 and the spacing member 36 . The PET film 50 extends in the tangential direction of the nip portion N. As shown in FIG. A push-pull gauge 51 is connected to one longitudinal end of the PET film 50 . In this state, the photosensitive drum 21 is fixed, the pressing force of the pressing mechanism 13 is kept constant, and the push-pull gauge 51 is pulled in the tangential direction of the nip portion N. As shown in FIG. FIG. 6 shows the measured value F (pulling force) indicated by the push-pull gauge 51 at this time.

As shown in FIG. 6, the measured value F of the push-pull gauge 51 linearly increases due to the static frictional force of the cleaning member 37 (a in FIG. 6) at the initial stage of measurement. When the maximum static friction force of the cleaning member 37 is exceeded, the measured value F of the push-pull gauge 51 changes as a constant dynamic friction force (b in FIG. 6). This dynamic friction force is represented by the sum of the rotational load force of the spacing member 36 and the pressure force of the pressure mechanism 13 . Assuming that the pressure applied by the pressure mechanism 13 is constant, the rotational load force of the spacing member 36 can be read as the dynamic friction force, that is, the measured value F of the push-pull gauge 51 . The measured value F of the push-pull gauge 51 is recorded in the storage unit 11 or the like of the image forming apparatus 1 as the rotational load force F of the spacing member 36 .

FIG. 7 is a graph showing the relationship between the rotational load force F of the spacing member 36 and the wear rate. The wear rate of the spacing member 36 is the wear amount of the spacing member 36 per unit driving time of the developing section 30 . Information representing the relationship between the rotational load force F and the wear rate of the spacing member 36 in FIG. 7 is stored in advance in the storage unit 11 or the like. As a result, when the rotational load force F of the spacing member 36 is measured and recorded using the push-pull gauge 51 before the image forming apparatus 1 is started to be used, the wear rate of the spacing member 36 can be obtained from the information shown in FIG. can be obtained.

FIG. 8 is a graph showing the relationship between the wear amount of the spacing member 36 and the rate of change in toner consumption. As shown in FIG. 8, in the case of the comparative example in which the image forming conditions are not corrected (one-dot chain line in FIG. 8), the amount of wear of the interval holding member 36 increases, and the developing performance changes. increases beyond the upper limit.

On the other hand, as shown as an example (solid line in FIG. 8), the image forming apparatus 1 of the present embodiment adjusts the wear amount of the spacing member 36 so that the rate of change in toner consumption does not exceed the upper limit. A predetermined threshold value is provided, and the image forming conditions are corrected when the wear amount reaches the threshold value. The threshold for the wear amount of the spacing member 36 is calculated from the driving time of the developing section 30 based on the wear rate of the spacing member 36 (=wear amount/driving time of the developing section 30).

Specifically, the control unit 10 of the image forming apparatus 1 determines the rotation load force of the interval holding member 36 measured before the image forming apparatus 1 is started to be used, and the rotation load force of the interval holding member 36 per unit driving time of the developing unit 30. The wear amount of the spacing member 36 is calculated based on the information representing the relationship between the wear amount and the wear rate, and the accumulated driving time of the developing unit 30. When the calculated wear amount reaches a predetermined threshold value, an image is displayed. An image forming condition correction process for correcting the forming conditions is executed.

According to the above configuration, the interval holding member differs for each image forming apparatus based on the rotation load force of the interval holding member 36, the wear rate of the interval holding member 36, and the cumulative driving time of the developing unit 30, which differ for each image forming apparatus. 36 wear amount can be grasped. Then, based on the threshold for the amount of wear, it is possible to appropriately correct the image forming conditions for each apparatus.

FIG. 9 is a graph showing changes in the rate of change in the amount of toner consumption in the image forming apparatuses of Example and Comparative Example. In each of the image forming apparatus 1 of the example and the image forming apparatus of the comparative example, the influence of the presence or absence of the image forming condition correction process on the toner consumption change rate was evaluated with respect to the wear of the interval holding member 36 . Note that the initial value of the toner consumption change rate is 100%.

In the image forming apparatus 1 of the embodiment, for example, the control unit 10 changes the DC voltage among the development voltages applied to the development roller 34 during image formation as the image formation condition correction processing. The voltage application unit 12 applies a developing voltage obtained by superimposing a DC voltage and an AC voltage to the developing roller 34 . In the image forming apparatus of the comparative example, the developing voltage was not changed.

Other configuration and operating conditions of the image forming apparatus are as follows: image forming speed of 40 sheets/min; peripheral speed of photosensitive drum of 240.28 mm/sec; diameter of photosensitive drum of 30 mm; The distance is 0.3 mm, and the photosensitive layer is an amorphous silicon layer. Two types of cleaning members were used. The cleaning members of Example 1 and Comparative Example 1 had a thickness of 2 mm (compression rate of 20%) and a [rotational load force/wear rate] of 1.5 N/(3 μm/h). The cleaning members of Example 2 and Comparative Example 2 had a thickness of 3 mm (compressibility of 46%) and a [rotational load force/wear rate] of 3 N/(6 μm/h).

As can be seen from FIG. 9, in the case of the image forming apparatus of the comparative example, as the driving time of the developing unit 30 increases, the rate of change in the amount of toner consumption increases substantially linearly.

On the other hand, in the case of the image forming apparatus 1 of the example, even if the driving time of the developing unit 30 increases, the rate of change in the amount of toner consumption hardly increases. According to the configuration of the embodiment, an increase in toner consumption can be suppressed by changing the developing voltage. That is, it is possible to appropriately correct the image forming conditions for each apparatus based on the amount of wear of the spacing member 36 that differs for each apparatus.

In addition, the control section 10 changes the exposure conditions for the photosensitive drum 21 by the exposure section 5, for example, as another image forming condition correction process. According to this configuration, it is possible to appropriately correct the surface potential difference of the photoreceptor drum 21 for each device based on the amount of wear of the spacing member 36 that differs for each device. As a result, an increase in toner consumption can be suppressed, and image quality can be improved.

It should be noted that the image forming apparatus 1 can individually calculate the wear amount of the interval holding members 36 at both ends of the rotating shaft 34x of the developing roller 34 . Then, the control unit 10 changes the exposure conditions to different exposure conditions on one side and the other side in the axial direction of the photosensitive drum 21 based on the amount of wear of the spacing members 36 at both ends of the rotating shaft 34x of the developing roller 34. .

According to this configuration, it is possible to appropriately correct the surface potential difference of the photoreceptor drum 21 for each device based on the amount of wear of the interval holding member 36 which differs at each end of the rotating shaft 34x of the developing roller 34. . Therefore, it is possible to more effectively suppress an increase in toner consumption and improve image quality.

Further, the control section 10 executes image forming condition correction processing every time the developing section 30 is driven for a predetermined period of time. For example, in FIG. 8, the image forming apparatus 1 of the embodiment executes the image forming condition correction process each time the developing unit 30 is driven for a predetermined period of time, so that the toner consumption change rate intermittently increases from near the upper limit value to near 100%. It can be seen that the

According to this configuration, frequent execution of the image forming condition correction process can be suppressed. In other words, it is possible to efficiently execute the image forming condition correction process, effectively suppress the increase in toner consumption, and improve the image quality.

Further, the control unit 10 starts executing the image forming condition correction process after a predetermined time has passed since the image forming apparatus 1 is started to be used. For example, in FIG. 9, the control unit 10 of the embodiment starts executing the image forming condition correction process after a predetermined time T0 has elapsed from the start of use of the image forming apparatus 1 . According to FIG. 9, during the predetermined time T0, the value of the toner consumption amount change rate of the example and the value of the comparative example overlap, and it can be seen that the image forming condition correction process is not executed in the example.

According to this configuration, at the beginning of use of the image forming apparatus 1, the image forming condition correction process can be executed efficiently without the risk of a large increase in toner consumption or a drastic deterioration in image quality. . Therefore, it is possible to effectively suppress an increase in toner consumption and improve image quality.

Further, as the wear of the spacing member 36 progresses, the correction of the image forming conditions may reach its limit. As a result, there is concern that the amount of toner consumed will increase and the image quality will deteriorate. Therefore, the control unit 10 displays information prompting replacement of the developing unit 30 on the display unit 2D when the correction of the image forming conditions reaches the predetermined upper limit value or lower limit value. According to this configuration, when the wear of the interval holding member 36 progresses, the developing section 30 can be replaced before problems such as an increase in toner consumption and deterioration in image quality occur.

Although the embodiment of the present invention has been described above, the scope of the present invention is not limited to this, and various modifications can be made without departing from the gist of the invention.

For example, in the above embodiment, the image forming apparatus 1 is an image forming apparatus for monochrome printing that forms a monochrome image, but is not limited to such a model. The image forming apparatus may be an image forming apparatus for color printing that forms a color image by superimposing a plurality of color images.

INDUSTRIAL APPLICABILITY The present invention can be used in image forming apparatuses.

REFERENCE SIGNS LIST 1 image forming apparatus 2 main body 2D display unit 5 exposure unit 7 transfer unit 8 fixing unit 10 control unit 11 storage unit 12 voltage application unit 13 pressure mechanism 20 image forming unit 21 photoreceptor drum (image carrier)
21a photosensitive layer 30 developing section 31 developing container 34 developing roller (toner carrier)
34x rotating shaft 36 spacing member 37 cleaning member

Claims (7)

an image carrier having a photosensitive layer on its surface;
a charging unit that charges the surface of the image carrier;
an exposure unit that forms an electrostatic latent image on the surface of the image carrier charged by the charging unit;
a developing unit that supplies toner to the surface of the image carrier and develops the electrostatic latent image to form a toner image;
a voltage applying unit that applies a voltage to the charging unit and the developing unit;
a pressurizing mechanism that brings the developing unit into contact with the image carrier and pressurizes it;
a control unit that controls operations of the image carrier, the charging unit, the exposure unit, the development unit, and the voltage application unit;
In an image forming apparatus comprising
The developing unit is
a toner carrier arranged to face the image carrier and carrying the toner supplied to the surface of the image carrier;
a gap holding member that is rotatably supported by both ends of the rotating shaft of the toner carrier and that contacts the surface of the image carrier to keep a constant gap between the image carrier and the toner carrier;
a cleaning member that contacts the surface of the spacing member and cleans the surface of the spacing member;
with
The control unit
Information representing the relationship between the rotational load force of the spacing member measured before the start of use of the image forming apparatus and the wear rate, which is the amount of wear of the spacing member per unit driving time of the developing unit; calculating the amount of wear of the spacing member based on the accumulated driving time of the developing unit, and executing image forming condition correction processing for correcting the image forming conditions when the calculated amount of wear reaches a predetermined threshold value; An image forming apparatus characterized by: The voltage applying section applies a development voltage obtained by superimposing a DC voltage and an AC voltage to the toner carrier,
2. The image forming apparatus according to claim 1, wherein, as the image forming condition correction processing, the control section changes the DC voltage among the developing voltages applied to the toner carrier during image formation. 2. The image forming apparatus according to claim 1, wherein said control section changes the exposure condition of said image bearing member by said exposing section as said image forming condition correction processing. the amount of wear of the spacing members at both ends of the rotating shaft of the toner carrier can be individually calculated;
The control section changes the exposure condition to be different between one side and the other side in the axial direction of the image carrier based on the amount of wear of the spacing members at both ends of the rotation shaft of the toner carrier. 4. The image forming apparatus according to claim 3, wherein: 5. The image forming apparatus according to claim 1, wherein the control section executes the image forming condition correction process each time the developing section is driven for a predetermined period of time. 6. The image forming apparatus according to any one of claims 1 to 5, wherein the control section starts executing the image forming condition correction process after a predetermined time has passed since the image forming apparatus is started to be used. A display unit for displaying information related to image formation is provided,
3. The control unit displays information prompting replacement of the developing unit on the display unit when the correction of the image forming conditions reaches a predetermined upper limit value or a lower limit value. Item 7. The image forming apparatus according to any one of Items 6 to 7.

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