JP5321261B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, there is known an image forming apparatus that forms a toner image on an image holding member, transfers the toner image onto a recording medium, and fixes the toner image. Some of these image forming apparatuses include a cleaning blade that removes deposits remaining on the image carrier after the toner image is transferred.

  Patent Document 1 proposes a technique for providing a conductive layer on both the cleaning blade and the image carrier, and detecting the turning of the cleaning blade by contacting the conductive layer when the cleaning blade is turned up.

  Patent Document 2 proposes a technique for dynamically observing internal strain applied to the cleaning blade by a photoelastic method in a state where the cleaning blade is in contact with the image carrier.

  Further, Patent Document 3 proposes a technique for correcting the distortion of the cleaning blade by attracting a magnetic body attached to the cleaning blade with a solenoid coil.

Japanese Patent Application Laid-Open No. 06-067583 JP 2003-005580 A JP 2003-005597 A

  An object of the present invention is to provide an image forming apparatus in which image transfer from the surface of an image carrier is stable.

An image forming apparatus according to claim 1 is provided.
An image carrier that forms an image on the surface and holds the image;
An image forming unit that holds toner and forms a toner image on the surface of the image carrier using the toner;
A transfer portion for transferring the toner image formed on the surface of the image carrier onto the transfer target;
A cleaning member that contacts the surface of the image carrier and removes deposits from the surface;
A measuring unit that measures distortion of the cleaning member; and a toner replacement unit that replaces at least a part of the toner held by the image forming unit with new toner according to a measurement result by the measuring unit;
It is provided with.

An image forming apparatus according to claim 2
A toner supply unit for supplying toner to the image forming unit when the image forming unit consumes retained toner in forming the toner image;
The toner replacement unit is configured to cause the image forming unit to form a toner image in accordance with a measurement result by the measurement unit and to consume the retained toner.

An image forming apparatus according to claim 3
The image forming unit forms an electrostatic latent image on the surface of the image holding member, and forms a toner image on the surface of the image holding member by attaching charged toner to the latent image. It is characterized by.

An image forming apparatus according to claim 4
The image forming unit forms an electrostatic latent image on the surface of the image carrier, and the toner in the developer containing toner and particles having a smaller volume average particle diameter than the toner is formed on the latent image. A toner image is formed on the surface of the image holding member by adhering.

An image forming apparatus according to claim 5
The volume average particle diameter of the particles is 100 to 800 nm.

An image forming apparatus according to claim 6
The cleaning member includes a member main body that comes into contact with the surface of the image carrier and removes deposits from the surface, and a sensor unit that contacts the member main body and outputs a signal corresponding to distortion of the member main body. And
The measurement unit measures distortion of the cleaning member using an output signal of the sensor unit.

An image forming apparatus according to claim 7 is provided.
The cleaning member includes the member main body, and a sensor unit made of a metal film attached to a location that avoids a location where the member main body contacts the surface of the image carrier.
The measurement unit measures distortion of the cleaning member using an output signal of the sensor unit representing the resistance of the metal film.

An image forming apparatus according to claim 8 is provided.
The cleaning member includes the member main body, and a sensor unit made of a metal film deposited in a place avoiding a place where the member main body contacts the surface of the image carrier.
The measurement unit measures distortion of the cleaning member using an output signal of the sensor unit representing the resistance of the metal film.

  According to the image forming apparatus of the first aspect, the image transfer from the surface of the image carrier is more stable than in the case where the toner replacement unit is not provided.

  According to the image forming apparatus of the second aspect, it is possible to replace the toner with simple control as compared with the case where this configuration is not provided.

  According to the image forming apparatus of the third aspect, the image transfer is stable even in the electrophotographic system.

  According to the image forming apparatus of the fourth aspect, the image transferability is stably improved.

  According to the image forming apparatus of the fifth aspect, the image transferability is more stably improved as compared with the case where the present configuration is not provided.

  According to the image forming apparatus of the sixth aspect, it is possible to detect a decrease in image transferability with a simple configuration.

  According to the image forming apparatus of the seventh aspect, even if the sensor unit is attached to the member main body, the deformation of the member main body is not hindered.

  According to the image forming apparatus of the eighth aspect, the followability of the sensor unit with respect to the member main body is higher than the case where the sensor unit is not a deposited metal film.

1 is a schematic configuration diagram of a printer. FIG. 2 is a perspective view from the laser exposure device side of the developing device shown in FIG. 1. FIG. 4 is an enlarged view of a cleaning blade tip in contact with the surface of a photoreceptor roll. It is a figure which shows a mode that the deposit of the contact part of the photoreceptor roll surface which rotates and the cleaning blade front-end | tip is occupied with the external additive. It is an external appearance perspective view of the cleaning blade in this embodiment. It is a figure which shows the detail of a strain gauge. It is a graph which shows the change of the resistance value of a strain gauge. It is an internal block diagram of the control part also shown by FIG. It is a detailed block diagram of the Wheatstone bridge circuit shown in FIG. It is a graph which shows the change of the resistance value of the strain gauge each arrange | positioned at the front and back of a cleaning blade.

  Hereinafter, embodiments of the image forming apparatus of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of a printer.

  The printer 1 shown in FIG. 1 generates a photoconductor roll 10, a charging roll 11 for applying a charge to the surface of the photoconductor roll 10, and laser exposure light based on an image signal transmitted from the outside. A laser exposure device 12 that irradiates the roll 10, a developing device 13 that contains a developer containing toner, an intermediate transfer belt 17 that circulates in the direction of arrow B, and a suspension roll on which the intermediate transfer belt 17 is suspended. 18, a belt cleaner 16 that cleans the surface of the intermediate transfer belt 17, a primary transfer roll 14 that transfers the toner image held on the surface of the photoreceptor roll 10 onto the intermediate transfer belt 17, and an intermediate transfer belt A secondary transfer roll 19 for secondarily transferring the transferred toner image onto the recording paper P conveyed in the direction of arrow C, and heating and heating the toner image transferred onto the recording paper P The fixing device 15 that fixes the toner image on the recording paper by pressing, the cleaning device 20 that cleans the surface of the photoreceptor roll 10, and the image data transmitted from the outside is received and processed to the laser exposure device 12. And a control unit 100 for transmission. The printer 1 is an embodiment of the image forming apparatus of the present invention.

  The developing device 13 rotates while facing the photoconductor roll 10 and conveys the developer to an area between the photoconductor roll 10 and a toner supply unit that supplies toner to the inside of the developing device 13. 130. The developer accommodated in the developing device 13 includes a magnetic carrier and an external additive in addition to the toner. The magnetic carrier is a charge imparting particle that frictionally charges the toner by friction with the toner, and is also a magnetic particle. The external additive is inorganic particles having a releasing function. Here, silica is employed as an example of the external additive. The external additive has a volume average particle diameter of 100 to 800 nm, more preferably 100 to 200 nm. The volume average particle size was measured using a laser diffraction particle size distribution analyzer (LA-700: manufactured by Horiba, Ltd.). As a measurement method, 2 g of a measurement sample was added to 50 ml of a surfactant, preferably a 5% aqueous solution of sodium alkylbenzenesulfonate, and dispersed for 2 minutes using an ultrasonic disperser (1000 Hz) to prepare a sample. The volume average particle diameter for each channel is accumulated from the smaller volume average particle diameter, and the volume average particle diameter is determined when the accumulation reaches 50%. The material of the external additive is an inorganic material, preferably silica, more preferably amorphous silica. The external additive may be surface-treated by a known method such as silane coupling agent or silicon oil treatment.

  FIG. 2 is a perspective view of the developing device shown in FIG. 1 from the laser exposure device side.

  FIG. 2 shows the developing device 13 including a developing roll 131, a developer containing tank 132 for containing the developer, and a stirring and conveying member 133 for stirring and conveying the developer.

  The developer storage tank 132 has a first storage chamber 132a adjacent to the development roller 131 and a second storage chamber adjacent to the first storage chamber 132a by a wall 1321 extending in parallel with the development roller 131. 132b. In each of the first storage chamber 132a and the second storage chamber 132b, one agitation transport member 133 is provided. Specifically, the agitation transport member 133 has a spiral fin around the rod. It has a provided structure. As the agitating and conveying member 133 provided in each of the first storage chamber 132a and the second storage chamber 132b rotates in the opposite directions, the developer stored in the developer storage tank 132 is stirred around the wall 1321. Cycle counterclockwise. Inside the developer storage tank 132, the toner and the magnetic carrier are agitated by the agitating / conveying member 133, so that the toner is negatively charged and the magnetic carrier is positively charged. For this reason, the negatively charged toner adheres electrostatically to the magnetic carrier.

  In addition, the developing device 13 includes a toner concentration sensor 134 that detects the toner concentration in the developer stored in the developer storage tank 132, and the toner supply unit 130 when the toner concentration detected by the toner concentration sensor 134 decreases. And a density control unit 135 that issues a toner supply instruction. FIG. 2 shows a supply port 132 c through which the toner supply unit 130 supplies toner to the developer storage tank 132. A combination of the toner density sensor 134, the toner supply unit 130, and the density control unit 135 corresponds to an example of the toner supply unit according to the present invention. The photoreceptor roll 10 corresponds to an example of the image carrier according to the present invention, and the combination of the charging roll 11, the laser exposure device 12, and the developing device 13 is an example of the image forming unit according to the present invention. Equivalent to. Further, the primary transfer roll 14 corresponds to an example of a transfer portion according to the present invention, and the intermediate transfer belt 17 corresponds to an example of a transfer target according to the present invention. Although the printer 1 is a monochromatic image dedicated machine, the present invention may be applied to a color image machine.

  The flow of the image forming operation in the printer 1 will be briefly described.

  In the printer 1 shown in FIG. 1, an electric charge is applied to the surface of the photoreceptor roll 10 rotating in the direction of arrow A by the charging roll 11, and the image transmitted from the outside to the surface of the photoreceptor roll 10 to which the charge is applied. The laser exposure light based on the signal is irradiated from the laser exposure device 12, whereby an electrostatic latent image is formed on the surface. The developer accommodated in the developing device 13 is supplied to the surface of the developing roll 131 and is carried to a region between the developing roll 131 and the photoreceptor roll 10, and the photoreceptor roll is transported by the toner in the carried developer. An electrostatic latent image of 10 surfaces is developed. The toner image obtained by this toner development is transferred to the intermediate transfer belt 17 by the primary transfer roll 14. The toner image on the intermediate transfer belt is transferred onto the recording paper by the secondary transfer roll 19, and then the toner image on the recording paper is melted and fixed on the recording paper by the fixing device 15 that heats and pressurizes the toner image. Is done. The adhering matter adhering to the portion of the photoreceptor roll 10 after the transfer of the toner image is downstream of the primary transfer roll 14 in the rotation in the direction of arrow A and upstream of the charging roll 11 and the photoreceptor roll 10. Is removed by scraping the cleaning blade 21 whose tip is in contact with the entire width along the rotation center. The removed deposit is stored in the deposit storage box 22.

  Here, the cleaning by the cleaning blade 21 on the surface of the photoreceptor roll 10 that is the object to be cleaned is a “stick-slip phenomenon” between the cleaning blade 21 in contact with the surface of the photoreceptor roll 10 and the surface of the photoreceptor roll 10. It is done by causing a phenomenon called "

  This stick-slip phenomenon is a phenomenon in which the “stick state” and the “slip state” are repeated. The “stick state” is a toner or silica on the surface of the photoreceptor roll by a cleaning blade whose tip contacts the surface of the rotating photoreceptor roll. The deposits made of external additives such as the above are removed, and as the removed deposits accumulate on the contact portion between the surface of the photoconductor roll and the tip of the cleaning blade, the force for entraining the tip of the cleaning blade gradually increases. As a result, the stress generated in the cleaning blade gradually increases. In addition, the “slip state” means that when the amount of deposits deposited on the contact portion between the photosensitive roll surface and the tip of the cleaning blade exceeds a certain level, the deposited deposit is broken by the cleaning blade, and the tip of the cleaning blade is A state in which the force of entrainment suddenly decreases. At the contact portion between the surface of the photoreceptor roll and the tip of the cleaning blade, cleaning that occurs due to repeated deposition (“stick state”) and collapse (“slip state”) of the deposit removed by the cleaning blade from the surface of the photoreceptor roll Cleaning is performed by the behavior of the blade tip.

  FIG. 3 is an enlarged view of the tip of the cleaning blade in contact with the surface of the photoreceptor roll.

  In FIG. 3, the external additive 200 and the toner 300 are deposited in the deposit in which deposits removed from the photoreceptor roll are deposited due to the tip of the cleaning blade being in contact with the photoreceptor roll rotating in the direction of the arrow. It shows a mix. As shown in FIG. 3, deposits mixed with toner and external additives are deposited on the contact portion between the surface of the rotating photoconductor roll and the tip of the cleaning blade, causing a stick state and distorting the cleaning blade. The stress that distorts the cleaning blade in this way becomes a force for removing the deposits on the photoreceptor roll, so that the external additive 200 and the toner 300 are further deposited on the tip of the cleaning blade, and the slip state is eventually reached. That is, the stick-slip phenomenon occurs due to the mixture of the external additive 200 and the toner 300 on the photoreceptor roll.

  However, when the proportion of toner in the deposits on the surface of the photoreceptor roll decreases, the proportion of toner in the deposit on the tip of the cleaning blade also decreases, and the above-described stick-slip phenomenon becomes difficult to occur.

  FIG. 4 is a diagram showing a state where deposits at the contact portion between the surface of the rotating photoconductor roll and the tip of the cleaning blade are occupied by the external additive.

  4 shows that the deposit on the contact portion between the rotating photoreceptor roll surface and the tip of the cleaning blade is occupied by the external additive 200 and the proportion of the toner is reduced, so that the distortion amount of the cleaning blade is shown in FIG. It is shown that it is less than shown. This is because, when the proportion of toner in the deposit is low, the viscosity of the deposit is also low, and the frictional force between the surface of the photoreceptor roll and the tip of the cleaning blade, which is the source of the action of entraining the tip of the cleaning blade. This is considered to be difficult to secure.

  By the way, in an image forming apparatus using a toner having a relatively high adhesiveness such as a low-temperature fixing toner that can be fixed even at a low temperature, in order to ensure transferability of the toner image formed on the surface of the photoreceptor roll, the separation is performed. In some cases, a developer in which inorganic particles such as silica having a mold property are mixed as an external additive is used. In an image forming apparatus using such a developer, a toner image formed on the surface of a photoconductor roll is formed on an intermediate transfer member or a recording sheet when a high image density image is formed after a long low-density image formation. There is a phenomenon that the transferability of the toner is lowered and it becomes difficult to obtain a desired image density. This is because an external additive that normally adheres to the toner surface and exerts a releasing action that prevents direct contact between the toner and the surface of the photoreceptor roll, the toner on the destination adheres with the carrier for a long time in the developing device. This is because the toner is buried in the toner as a result of the agitation, and the releasing function cannot be achieved. In particular, under high temperature and high humidity (temperature 28 ° C., humidity 85%), the toner having a reduced spacer effect has increased liquid cross-linking force and specular adhesion, and transfer from the photoreceptor to the intermediate transfer belt or from the intermediate transfer belt to the paper. The efficiency is lowered, a sufficient image density cannot be obtained, and image defects are likely to occur.

  Therefore, in order to suppress a decrease in toner image transferability, it is necessary to replace the toner contained in the developing device.

  When the distortion of the cleaning blade 21 after the toner patch of a predetermined density formed on the surface of the photoconductor roll 10 is removed from the surface of the photoconductor roll 10 becomes larger than the previous time, it is removed and deposited by the cleaning blade 21. This means that the toner ratio in the adhered matter has increased, that is, the transfer residual toner has increased due to the deterioration in transferability even though the toner patch having the same density is produced. It can be estimated that the degree of burying of the external additive in the toner surface accommodated is larger than the previous time. Therefore, in the printer 1, when the degree of burying estimated using the toner patch of a predetermined density exceeds a predetermined reference, that is, when the degree of distortion of the cleaning blade 21 is larger than a certain level, the developing device 13 Replacing the toner of the toner suppresses a decrease in toner image transferability.

  In the following, first, estimation of the degree of burying of the external additive on the toner surface of the toner stored in the developing device 13 will be described.

  The lower the transferability of the toner image formed on the surface of the photoreceptor roll, the greater the amount of residual toner on the surface of the photoreceptor roll. When the residual toner is removed by the cleaning blade, it accumulates on the tip of the blade. The percentage of toner in the deposit is high. As a result, as described above, the frictional force between the blade tip and the surface of the photoreceptor roll increases, and the distortion of the cleaning blade increases. On the other hand, the higher the transferability of the formed toner image, the smaller the amount of residual toner on the surface of the photoreceptor roll, and the lower the proportion of toner in the deposit that accumulates on the blade tip. As a result, the frictional force between the blade tip and the surface of the photoreceptor roll becomes low, and the distortion of the cleaning blade becomes small. Therefore, in the printer 1 of the present embodiment, a strain gauge 22 whose resistance value changes according to the strain is attached to the cleaning blade 21, and a toner patch having a constant density is applied to the photoreceptor roll 10 during normal image formation. The transfer residual toner on the surface of the photoreceptor roll after the toner patch is transferred to the intermediate transfer belt 17 by operating the primary transfer roll 14 in the same manner as in normal image formation is formed at the tip of the blade. The degree of distortion of the cleaning blade 21 is detected at the time when it is deposited, and the degree of burying of the external additive on the toner surface is estimated. The toner patch transferred to the intermediate transfer belt 17 is cleaned by the belt cleaner 16 without being transferred to the recording paper P.

  Next, a method for detecting the degree of distortion of the cleaning blade will be described.

  FIG. 5 is an external perspective view of the cleaning blade in the present embodiment.

  FIG. 5 shows a state in which the strain gauge 22 shown in FIG. 1 is attached to the central portion of the surface 211 of the cleaning blade 21. The strain gauge 22 corresponds to an example of a sensor unit according to the present invention, and the cleaning blade 21 corresponds to an example of a member main body according to the present invention.

  In this printer 1, a signal indicating the magnitude of the resistance value of the strain gauge 22 attached to the central portion of the surface 211 of the cleaning blade 21 is detected, and the degree of distortion of the cleaning blade 21 is estimated by estimating the magnitude of the frictional force at the blade tip. Is estimated.

  Hereinafter, the details of the strain gauge 22 attached to the cleaning blade 21 and the relationship between the strain of the cleaning blade 21 and the resistance value of the strain gauge 22 will be described first.

  FIG. 6 is a diagram showing details of the strain gauge.

  The strain gauge 22 shown in FIG. 6 is a metal film composed of a gauge pattern portion 221 made of a narrow pattern connected in a zigzag shape and gauge tab portions 222 connected to both ends of the gauge pattern portion 221, respectively. The gauge pattern portion 221 and the gauge tab portion 222 are attached to the cleaning blade 21 by vapor deposition. For this reason, the strain gauge 22 is difficult to peel off from the surface 211 of the cleaning blade 21 and has high followability to the surface 211 of the cleaning blade 21.

  When the photosensitive roll 10 rotates in the direction of arrow A shown in FIG. 5, the cleaning blade 21 curves so that the tip 210 side protrudes toward the front side in FIG. 6, so that the gauge pattern portion 221 contracts in the L direction. As a result, the cross-sectional area of the gauge pattern portion 221 is increased and the distance is slightly reduced, so that the resistance value of the strain gauge 22 is reduced.

  Further, the strain gauge 22 is deposited at a distance from the tip 210 of the cleaning blade 21 so as not to hinder the distortion of the tip 210 that greatly affects the strain of the entire cleaning blade.

  The gauge tab portion 222 has a pattern wider than the gauge pattern portion 221 so that the connection of the gauge lead 223 does not affect the expansion and contraction of the gauge pattern portion 221.

  The gauge length L of the gauge pattern portion 221 is preferably in the range of 0.2 mm to 5 mm. Moreover, it is preferable that the gauge width W of the gauge pattern part 221 exists in the range of 0.5 mm-5 mm. If it is smaller than this range, processing with high accuracy is required, and noise to the signal increases. On the other hand, if the ratio is larger than this range, the ratio of the cleaning blade 21 to the surface 212 increases, so that the followability of the resistance value against the distortion of the cleaning blade 21 decreases. The gauge tab portion 222 is connected to the control unit 100 by a gauge lead 223. The material of the metal film is selected from the group consisting of aluminum, zinc, nickel, titanium, vanadium, chromium, tantalum, iron, manganese, silicon, and alloys, oxides, nitrides, and silicides thereof. Is mentioned.

  FIG. 7 is a graph showing a change in the resistance value of the strain gauge.

  FIG. 7 shows a change in the resistance value of the strain gauge 22 deposited on the surface 211 of the cleaning blade 21.

  A solid line in FIG. 7 indicates a change in the resistance value of the strain gauge 22 in an inappropriate state with a large amount of residual toner, and a dotted line in FIG. 7 indicates a change in the resistance value of the strain gauge 22 in an appropriate state with a small amount of residual toner. Is shown.

  In FIG. 7, in the above-described inappropriate state, the resistance value Rv of the strain gauge 22 was Rv0 while the photoreceptor roll 10 was stopped, but greatly decreased to Rv1 while the photoreceptor roll 10 was rotating. The state of doing is shown. On the other hand, in the above-described proper state, the resistance value Rv of the strain gauge 22 was Rv0 in the same manner as the inappropriate state while the photosensitive roll 10 was stopped. Compared to the state, the frictional force between the tip 210 of the cleaning blade 21 and the photoreceptor roll 10 is small, and the distortion of the cleaning blade 21 is also small, so that it only decreases to Rv2 that is larger than Rv1 in the inappropriate state. Thus, the resistance value of the strain gauge 22 reflects the amount of residual toner.

  Next, a method for detecting a signal indicating the magnitude of the resistance value of the strain gauge 22 will be described.

  FIG. 8 is an internal block diagram of the control unit also shown in FIG.

  The control unit 100 shown in FIG. 8 includes a Wheatstone bridge circuit 101, a detection unit 102, a determination unit 103, and a data processing unit 104. The combination of the Wheatstone bridge circuit 101 and the detection unit 102 corresponds to an example of the measurement unit according to the present invention, and the combination of the determination unit 103 and the data processing unit 104 is an example of the toner replacement unit according to the present invention. It corresponds to.

  FIG. 9 is a detailed block diagram of the Wheatstone bridge circuit shown in FIG.

  A Wheatstone bridge circuit 101 shown in FIG. 9 includes a first resistance element 1011 having a resistance value R1, a second resistance element 1012 having a resistance value R2, a third resistance element 1013 having a resistance value R3, and a DC power source 1010. In the circuit 101, a strain gauge 22 whose resistance value Rv changes is used as a fourth resistance element.

  A DC power source 1010 is connected to the first connection point A between the strain gauge 22 and the third resistance element 1013 and the second connection point B between the first resistance element 1011 and the second resistance element 1012. . The third connection point C between the first resistance element 1011 and the strain gauge 22 and the fourth connection point D between the second resistance element 1012 and the third resistance element 1013 are connected to the third connection point C. A detecting unit 102 for measuring a potential difference between the potential of the second connection point D and the potential of the fourth connection point D is connected.

  Here, when the following expression (1) is established, the potential difference measured by the detection unit 102 is zero.

Rv / R1 = R3 / R2 (1)
In the Wheatstone bridge circuit 101, the above equation (1) is established according to the resistance value Rv0 of the strain gauge 22 when the cleaning blade 21 is in a state of small strain as shown in FIG. 3, that is, Rv0. The other resistance values R1, R2, and R3 are set so that / R1 = R3 / R2 is satisfied. When the cleaning blade 21 changes from a state with a small strain as shown in FIG. 3 to a state with a large strain as shown in FIG. 2, the resistance value Rv of the strain gauge 22 becomes Rv1 smaller than Rv0 described above. The voltage drop caused by the resistance of the strain gauge 22 is reduced. Then, the potential Vc at the third connection point C becomes higher than the potential Vd at the fourth connection point D, and a potential difference is generated. Therefore, the potential difference (Vc−Vd> = 0) detected by the detection unit 102 increases as the resistance value Rv of the strain gauge 22 decreases, that is, as the strain of the cleaning blade 21 increases. Therefore, the potential difference detected by the detection unit 102 increases as the above-described appropriate state is changed to the inappropriate state. The voltage drop corresponds to an example of the output signal referred to in the present invention. Returning to FIG.

  The detection unit 102 transmits a signal according to the detected potential difference, that is, a signal having a higher level as the detected potential difference is larger to the determination unit 103 shown in FIG. 8 in real time.

  The determination unit 103 determines whether or not the level of the signal transmitted from the detection unit 102 exceeds a preset reference level, and determines that a signal having a level exceeding the reference level has been transmitted. That is, when it is determined that the transferability of the toner is lower than a preset reference and the amount of residual toner is increased, the toner is currently stored in the developing device 13 in order to suppress the decrease in toner transferability. The deteriorated toner whose transferability has deteriorated due to the external additive buried in the surface of the toner particles is replaced by the following means.

  This toner replacement is started by transmission of image data representing a solid image from the determination unit 103 to the data processing unit 104.

  As described above, the data processing unit 104 receives image data transmitted from the outside, processes the image data, and transmits the image data to the laser exposure unit 12. Image data representing an A3 size solid image is transmitted from the determination unit 103. Then, this is also processed and transmitted to the laser exposure device 12.

  The laser exposure device 12 irradiates the surface of the photoreceptor roll 10 with laser exposure light in accordance with a signal representing three A3-size solid images transmitted from the data processing unit 104. As a result, a latent image corresponding to the solid image is formed on the surface of the photoreceptor roll 10, and the latent image is developed with toner by the developing device 13.

  The developing device 13 consumes a large amount of toner along with toner development for the electrostatic latent image formed in accordance with the image signal. For this reason, the toner concentration in the developer accommodated in the developing device 13 decreases. The density control unit 135 instructs the toner supply unit 130 to supply toner while the toner density detected by the toner density sensor 134 is below a preset density threshold. As a result, the developing device 13 replaces the toner by receiving a supply of new toner in exchange for consuming a large amount of the toner stored so far. As a result, the determination unit 103 transmits the image data representing the solid image to the data processing unit 104 by reducing the level of the signal from the detection unit 102 through the improvement of the transferability of the patch by improving the degree of deterioration of the toner as a whole. Ends. This completes the toner replacement. The solid image is also transferred to the intermediate transfer belt 17 and then scraped off from the intermediate transfer belt 17 by the belt cleaner 16 without being transferred to the recording paper P.

  In the embodiment described above, the strain gauge 22 is deposited only on the front surface 211 and the back surface 211 of the cleaning blade 21, but in the image forming apparatus of the present invention, as described below, cleaning is performed. Sensors may be deposited on both the front surface 211 and the back surface of the blade 21.

  FIG. 10 is a graph showing changes in resistance values of strain gauges respectively provided on the front and back surfaces of the cleaning blade.

  The graph shown in the upper part of the graph shown in FIG. 10 represents the same graph as the graph shown in FIG. 7, that is, the change in the resistance value of the strain gauge 22 arranged on the surface 211 of the cleaning blade 21. On the other hand, the lower part shows the change in the resistance value of the strain gauge 22 arranged on the back surface of the same cleaning blade 21.

  In FIG. 10, the resistance value of the strain gauge 22 disposed on the surface 211 of the cleaning blade 21 is lower when the tip 210 of the cleaning blade 21 is distorted than when it is not distorted. The resistance value of the strain gauge 22 arranged on the back surface of the cleaning blade 21 is distorted when the tip 210 of the cleaning blade 21 is distorted because the direction of the curve is opposite between the front surface and the back surface of the cleaning blade. It is shown that it rises more than if not.

  As described above, the resistance value of the strain gauge 22 reflects the distortion of the cleaning blade 21 regardless of whether it is the front surface 211 or the back surface of the cleaning blade 21. It may be only the back surface, and may be arranged on both the front and back surfaces.

  In the above embodiment, an example in which a metal film as a strain gauge is vapor-deposited on a cleaning blade has been described. However, in the present invention, a metal film as a strain gauge may be attached to the cleaning blade with an adhesive. Hereinafter, a case where a metal film is attached with an adhesive will be described.

  In this case, the length (gauge length) L and width (gauge width) W and the material of the metal thin film are the same as those of the strain gauge 22 shown in FIG. The film thickness is not particularly limited, but a film having a thickness of several μm is preferably used in order to increase productivity. In order to detect the distortion of the cleaning blade with high accuracy, it is preferable to use a cleaning blade having a thickness of 0.1 μm to 2.0 μm. Further, the adhesive includes a thermosetting type and a liquid type. As the thermosetting adhesive, epoxy resin, phenol resin, polyurethane resin, silicon resin, polyimide resin, or the like is used. As the liquid adhesive, a cyanoacrylate adhesive, an epoxy, a phenol epoxy, or the like is used.

  When the metal film is bonded with an adhesive as described above, the response is inferior to the amount of the adhesive as compared with the case where the metal film is deposited. Therefore, it is necessary to use the adhesive as thin as possible.

  In the above description, the printer is described as an example of the image forming apparatus according to the present invention. However, the image forming apparatus according to the present invention is not limited to a copying machine as long as it forms a toner image on the surface of the image carrier. A facsimile or the like may be used. Furthermore, as an image forming apparatus according to the present invention, an indirect transfer type printer that transfers a developed image onto a recording sheet via an intermediate transfer belt has been described as an example. However, the image forming apparatus of the present invention is a photoconductor roll. It may be a direct transfer type printer that directly transfers the developed image onto the conveyed recording paper using a transfer roll.

  Further, although silica has been described as an example of the inorganic particles in the present invention, the inorganic particles in the present invention may be alumina or titanium oxide as long as they have a releasing function.

DESCRIPTION OF SYMBOLS 1 Printer 10 Photoconductor roll 100 Control part 101 Wheatstone bridge circuit 102 Detection part 103 Judgment part 104 Data processing part 11 Charging roll 12 Laser exposure device 13 Developing device 130 Toner supply part 131 Developing roll 132 Developer storage tank 133 Stirring conveyance member 134 Toner density sensor 135 Density control unit 14 Primary transfer roll 15 Fixing device 16 Belt cleaner 17 Intermediate transfer belt 18 Suspension roll 19 Secondary transfer roll 20 Cleaning device 200 External additive 21 Cleaning blade 210 Tip 211 Surface 22 Strain gauge 221 Gauge pattern part 222 Gauge tab portion 223 Gauge lead 23 Deposited material storage box 300 Toner

Claims (8)

An image carrier that forms an image on the surface and holds the image;
An image forming unit that holds toner and forms a toner image on the surface of the image carrier using the toner;
A transfer portion for transferring the toner image formed on the surface of the image carrier onto the transfer target;
A cleaning member that contacts the surface of the image carrier and removes deposits from the surface;
A measuring unit that measures distortion of the cleaning member; and when the measurement result by the measuring unit is a measurement result that deviates from a predetermined reference , at least a part of the toner that the image forming unit holds is replaced with new toner. Toner replacement part to replace with;
An image forming apparatus comprising: A toner supply unit that supplies toner to the image forming unit when the image forming unit consumes retained toner in forming the toner image;
The image forming apparatus according to claim 1, wherein the toner replacement unit is configured to cause the image forming unit to form a toner image in accordance with a measurement result by the measurement unit and to consume the retained toner.   The image forming unit forms an electrostatic latent image on the surface of the image holding member, and forms a toner image on the surface of the image holding member by attaching charged toner to the latent image. The image forming apparatus according to claim 1, wherein:   The image forming unit forms an electrostatic latent image on the surface of the image carrier, and the toner in the developer containing toner and particles having a smaller volume average particle diameter than the toner is used as the latent image. 4. The image forming apparatus according to claim 1, wherein a toner image is formed on the surface of the image holding member by adhering.   The image forming apparatus according to claim 1, wherein the particles have a volume average particle diameter of 100 to 800 nm. The cleaning member includes a member main body that comes into contact with the surface of the image carrier and removes deposits from the surface, and a sensor unit that contacts the member main body and outputs a signal corresponding to distortion of the member main body. And
The image forming apparatus according to claim 1, wherein the measurement unit measures distortion of the cleaning member using an output signal of the sensor unit. The cleaning member includes the member main body and a sensor unit made of a metal film attached to a location that avoids a location where the member main body contacts the surface of the image carrier.
The said measurement part measures the distortion of the said cleaning member using the output signal of the said sensor part showing resistance of the said metal film, The any one of Claim 1 to 6 characterized by the above-mentioned. Image forming apparatus. The cleaning member includes the member main body and a sensor unit made of a metal film deposited in a place avoiding a place where the member main body contacts the surface of the image carrier.
8. The device according to claim 1, wherein the measurement unit measures distortion of the cleaning member using an output signal of the sensor unit representing the resistance of the metal film. Image forming apparatus.

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