JP2020008700A - Image formation device - Google Patents

Abstract

To correct transmittance with a transparent liquid as a reference, and to appropriately manage a supply amount of a developer in an image formation device.SOLUTION: An image formation device has: a liquid detection unit that has a liquid passage unit making a liquid pass through, a light source capable of adjusting light to a prescribed amount of light, and a light reception element receiving the light emitted from the light source; a liquid switch unit that switches a route of the liquid to be supplied to the liquid detection unit; a first liquid that flows into the liquid switch unit; a first liquid reservoir part that reserves the first liquid; a liquid storage unit that stores the liquid passing through the liquid detection unit; a second liquid that is supplied to the liquid storage unit not via the liquid detection unit; a second liquid storage unit that stores the second liquid; a third liquid that is stored in the liquid storage unit; and a liquid circulation route that causes the liquid switch unit to circulate the third liquid. The liquid switch unit has a function of switching the liquid to be supplied so as to supply any one of the first liquid and the third liquid upon supplying the liquid to the liquid detection unit, and makes a correction of a detection output by switching the liquid.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image forming apparatus that performs failure detection when adjusting a liquid concentration.

  A wet electrophotographic apparatus using a liquid developer has an advantage that cannot be realized by a dry electrophotographic apparatus, and its value is being reviewed in recent years. In other words, in a wet electrophotographic apparatus, a very fine toner having a submicron size can be used, so that high image quality can be realized and a texture comparable to that of printing can be obtained, and energy can be saved because a toner can be fixed on paper at a relatively low temperature. , And so on.

  2. Description of the Related Art Conventionally, an image forming apparatus using a liquid developer has a toner concentration detecting mechanism for determining the toner concentration in a developer by measuring transmittance with an optical sensor, and the developer is contained when measuring the toner concentration. Circulates clear liquid, measures the initial value in a state where the transmittance does not decrease due to the developer, and self-calibrates the decrease in the transmittance due to the contamination of the toner component that adheres to the window of the detection unit and penetrates. There is known a method for reducing an error in density detection due to dirt (Japanese Patent Application Laid-Open No. H11-163873).

  Patent Document 1 discloses that when a developer is replenished so as to have a predetermined density based on a detection result of toner density in a developing solution, or when the amount of replenishment is reduced and adjusted, the output is reduced due to contamination of a detection unit and the actual density is reduced. If the image looks darker, the image quality is guaranteed by correcting the initial value.

Japanese Patent No. 2695597

  However, the toner does not adhere to the window of the detection unit, the transmittance decreases, and the output does not reach a predetermined output, or a replenishment failure occurs due to a blockage of a circulation path when replenishing the developer. In some cases, a failure such as failure to reach a predetermined concentration may occur even if the above is performed.

  When the failure occurred, the contents of the failure were unclear, so that there was a possibility that the user or serviceman would perform unnecessary operations or replace parts.

  SUMMARY OF THE INVENTION It is an object of the present invention to correct the transmittance based on a transparent liquid in an image forming apparatus and appropriately manage the replenishment amount of a developer.

In order to achieve the above object, an image forming apparatus according to the present invention includes:
A liquid detection unit having a liquid passage unit that allows the liquid to pass therethrough, a light source that can be adjusted to a predetermined light amount, and a light receiving element that receives light emitted from the light source,
A liquid switching unit that switches a path of a liquid to be supplied to the liquid detection unit,
A first liquid flowing into the liquid switching unit;
A first liquid storage unit for storing the first liquid,
A liquid storage unit in which the liquid that has passed through the liquid detection unit is stored,
A second liquid supplied to the liquid storage unit without passing through the liquid detection unit,
A second liquid storage unit for storing the second liquid,
A third liquid stored in the liquid storage unit,
A liquid circulation path (206) for circulating the third liquid to the liquid switching unit, wherein:
The liquid switching unit, when supplying a liquid to the liquid detection unit, has a function of switching the liquid to be supplied to supply either the first liquid or the third liquid,
The detection output is corrected by switching the liquid.

  According to the present invention, an image forming apparatus that detects a failure in a developer adjustment system and maintains image quality with a simple configuration is proposed.

FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a schematic view of a developer supply unit according to the present invention. It is a schematic diagram of a density detection sensor in the present invention. It is a block diagram of a control circuit in the present invention. 5 is a timing chart of control in the present invention. 5 is a flowchart of control in the present invention. It is a flowchart of the control of the 2nd Example in this invention.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram of an image forming apparatus according to the present invention.

  The image forming apparatus 100 includes a developer supply unit 200 and an image forming unit 301.

  The paper feeding device 302 accumulates printing paper to be output, and sequentially feeds the printing paper to the image transfer unit as needed.

  306a to 306d are photosensitive drums, and 307a to 307d are laser scanner units. 308a to 308d are developing devices, 309 is an intermediate transfer belt as an image carrier, 303 is a secondary transfer roller, and 304 is a fixing device including a halogen heater and the like.

  The intermediate transfer belt 309 is supported by a belt drive roller 310, a stretching roller 311, a steering roller 312, and a secondary transfer roller 303, and is rotated at a predetermined speed by a rotation of the belt drive roller 310 by a motor (not shown). Rotate around.

  In the image forming unit 301, an electrostatic latent image is formed on each of the photosensitive drums 306a to 306d for each color by laser scanner units 307a to 307d using a semiconductor laser as a light source. Developed by 308a to 308d. Then, the toner images of each color developed on the photosensitive drums 306a to 306d are primarily transferred to the intermediate transfer belt 309. The four color toner images on the intermediate transfer belt 309 are transferred to recording paper by a secondary transfer roller 303, fixed on the recording paper by a fixing device 304, and discharged onto a paper discharge transport unit 305.

  The developer replenishing unit 200 has developer replenishing units 201a to 201d and carrier liquid replenishing units 202 corresponding to the respective colors, and the developing unit 308a to 308d in the image forming unit 301 adjusts the developing density to an appropriate density as necessary. Replenish the agent.

  The density patch detection sensor 313 reads a density patch before fixing transferred onto the intermediate transfer belt 309, and performs density adjustment during development so that a predetermined density is obtained based on the detection result.

  FIG. 2 is a schematic view of the developer supply unit according to the present invention.

  The developer supply unit 201 is supplied with the developer from the developer tank 203 for each color, and is adjusted to have a predetermined density in the mixer 204. The carrier liquid supply pipe 207 supplies the carrier liquid supplied from the carrier liquid supply unit 202 to the concentration detection sensor 210 via the switching valve 208. The concentration detection sensor 210 can perform concentration detection while only the carrier liquid passes. The switching valve 208 switches the path of the liquid to be supplied to the concentration detection sensor 210, and supplies a mixture in which the developer and the carrier liquid are mixed in the mixer 204 to the concentration detection sensor 210 by the liquid circulation pump 205. In the mixer 204, the developer from the developer tank 203 and the carrier liquid from the carrier liquid replenishment unit 202 are mixed, and the developer or the carrier liquid is supplied so as to have a predetermined concentration according to the detection result of the concentration detection sensor 210. Adjusted.

  FIG. 3 is a schematic diagram of the density detection sensor 210 according to the present invention.

  The light transmitting unit 213 is arranged so as to block the optical path of the light receiving unit 212 facing the light emitting unit 211, and the liquid to be detected is supplied from the liquid supply pipe 214 to the light transmitting unit 213 and discharged from the liquid discharge pipe 215. While the liquid is passing through the light transmitting part 213, light of a necessary amount for density detection is projected from the light emitting part 211, and the concentration of the liquid to be detected is detected based on the amount of light received by the light receiving part 212. I can do things.

  FIG. 4 is a block diagram of a control circuit according to the present invention.

  The CPU 102 on the control board 101 controls each unit according to the program written in the ROM 103. An image reading unit (not shown) reads a document image in accordance with the content input from the operation unit 104, and transfers a density patch prior to the output image when forming an output image by the image data forming unit 111. 313 detects the patch density. A correction value according to the LUT 106 serving as correction data for correcting the density of the output image is read from the detected patch density data, the density correction is performed by the image correction unit 105, and the developing bias voltage is adjusted appropriately by the high-voltage control unit 108. Control to an appropriate value.

  The density of the developer is detected by the density detection sensor 210 when the apparatus is started and every predetermined number of prints. The density detection sensor driving circuit 110 drives the density detection sensor 210 according to an instruction from the CPU 102, receives an output signal of the density detection sensor 210, and transmits the output signal to the CPU 102.

  The liquid circulation pump driving circuit 109 drives a liquid circulation pump 205 for circulating the developer in accordance with an instruction from the CPU 102 when the density detection is performed by the density detection sensor 210.

  The valve opening / closing control unit 209 controls opening / closing of a switching valve 208 to switch the liquid supplied to the concentration detection sensor 210 between the carrier liquid supplied from the carrier liquid supply pipe 207 and the developer supplied from the liquid circulation pipe in accordance with an instruction from the CPU 102.

  FIG. 5 is an example of a timing chart of control in the present invention.

  A sensor output voltage V is generated according to changes in the LED current I, the carrier liquid replenishment amount SC, the developer replenishment amount SD, and the liquid concentration D, and it can be determined whether a predetermined operation is performed.

In a state where the LED was turned off, the carrier liquid SC ₀ to replenish, satisfy the clear carrier liquid to a concentration sensor 201 parts. When the LED is turned on at the current value I ₀ at time T ₁ , the light is transmitted from the light transmitting part 213 through the carrier liquid and hardly attenuated to the light receiving part, and is observed as the first sensor output voltage V _0. You. Thus at time T _2, the LED current I LED light amount increases according to the amount of current when the I ₁ Hesa from I _0, an increase in the sensor output voltage corresponding to an increase in light intensity is observed, the sensor output voltage V is the It changes from one output voltage V ₀ to the second output voltage V _1.

If the first sensor output voltage V ₀ is not detected more than predetermined output voltage, light transmission part 213 it is determined to be a state where the quantity of light soiled with the developer are insufficient.

When the second sensor output voltage V ₁ is not detected as a change of a predetermined or more output voltages, will be the light amount of the LED is not sufficiently changed, it is determined that the light amount adjustment error due to abnormality of the lighting circuit.

The replenishment of carrier liquid is stopped at time T _3, when starting the supply of the developer liquid density D is darker, resulting sensor output V gradually decreases, the developer replenishing amount SD 0 at time T _4, the liquid concentration D _0, and the reach to the third sensor output voltage _{V 2.} If the third output voltage V ₂ is not a predetermined reduction, will be referred to increased concentrations of the solution was less, it is determined that supply error of the developer.

Further decreases gradually liquid concentration when replenishing again carrier liquid from time T _5, the carrier liquid replenishment amount SC 1 at time T _6, the liquid concentration D _1, and the fourth sensor output voltage V _3. If the fourth output voltage V ₃ is not a predetermined rise, will be referred to as density reduction of the solution was less, it is determined that supplementation error of the carrier liquid.

For returning the liquid that has been diluted by the replenishing of the carrier liquid to a predetermined concentration at time T _7, adjusted to be liquid concentration required for image formation is replenished again developer.

  FIG. 6 is a flowchart of an example of the control according to the present invention.

  When the density detection system check is started (S100), the carrier liquid is supplied to the density detection sensor 210 (S101), and the LED as the light emitting element is turned on (S102). The concentration detection is performed using only the carrier liquid, and the first output voltage is set (S103). When the first output voltage is equal to or higher than the predetermined reference value (S104), since there is a sufficient amount of transmitted light, it is determined that the light transmitting portion 213 is not stained, and the LED current is increased (S105). And the second output voltage is obtained (S106). When the first output voltage level is equal to or lower than the predetermined reference value (S104), it can be determined that the light transmitting portion 213 of the density detection sensor 210 is contaminated with the developer and the amount of light is insufficient. (S115).

  When the second output voltage is higher than the first output voltage (S107), it can be confirmed that the light amount of the LED has changed. In this state, the switching valve 208 is switched to supply the developer to the density detection sensor 210 (S108). The developer is supplied, the density is detected in a state where the liquid density is increased, and a third output voltage is set (S109). If the second output voltage level has not risen above the first output voltage level (S107), it can be determined that the light amount of the LED has not changed, and a light amount adjustment error is made (S116). If the third output voltage is lower than the second output voltage (S110), it is determined that the developer has been supplied, and the switching valve 208 is switched again to supply the carrier liquid to the density detection sensor 210. (S111). The concentration is detected while the carrier liquid is supplied, and the fourth output voltage is set (S112). If the third output voltage level has not dropped below the second output voltage level (S110), it can be determined that the developer has not been replenished, and a developer replenishment error is determined (S117). If the fourth output voltage is higher than the third output voltage (S113), the check is terminated assuming that the supply of the carrier liquid has been performed (S114). If the fourth output voltage level has not risen above the third output voltage level (S113), it can be determined that the carrier liquid has not been replenished, and a carrier liquid replenishment error is determined (S118).

  As described above, the operation of the liquid circulation mechanism can be confirmed with a simple configuration, and a failure of the developer adjustment mechanism can be detected.

  Further, detection may be performed as needed while replenishing the carrier liquid and the developing solution, and a plurality of data may be obtained. May be performed.

  FIG. 7 is an example of a flowchart of control according to the second embodiment of the present invention.

  When the concentration detection system check is started (S200), the carrier liquid is supplied to the concentration detection sensor 210 (S201), and the LED as the light emitting element is turned on (S202). The concentration detection is performed using only the carrier liquid, and the first output voltage is set (S203).

  When the first output voltage level is measured (S203), if it is lower than the predetermined reference voltage (S205), the mode is shifted to the window dirt washing mode (S216), and the carrier liquid is circulated to wash the window dirt. Then, the output voltage level is measured again (S203), and if the number of repetitions N exceeds the predetermined number A and remains below the reference voltage, a window dirt error is determined (S217).

  Hereinafter, S206 to S215 are the same as S105 to S114 in FIG.

  As a method for cleaning in the window dirt cleaning mode, a configuration in which a wiper or the like is installed to scrape dirt attached to the window may be used, or a configuration in which vibration is applied by ultrasonic waves or the like to shake off dirt may be used. .

108 high pressure control unit, 109 liquid circulation pump drive circuit,
110 density detection sensor drive circuit, 200 developer supply section,
201 developer supply unit, 202 carrier liquid supply unit,
203 developer tank, 204 mixer, 205 liquid circulation pump,
206 liquid circulation pipe, 207 carrier liquid supply pipe, 208 switching valve,
209 valve opening / closing control unit, 210 concentration detection sensor, 211 light emitting unit,
212 light receiving section, 213 light transmitting section, 214 liquid supply pipe, 215 liquid discharge pipe

Claims (5)

A liquid detection unit having a liquid passage unit that allows the liquid to pass therethrough, a light source that can be adjusted to a predetermined light amount, and a light receiving element that receives light emitted from the light source,
A liquid switching unit that switches a path of a liquid to be supplied to the liquid detection unit,
A first liquid flowing into the liquid switching unit;
A first liquid storage unit for storing the first liquid,
A liquid storage unit in which the liquid that has passed through the liquid detection unit is stored,
A second liquid supplied to the liquid storage unit without passing through the liquid detection unit,
A second liquid storage unit for storing the second liquid,
A third liquid stored in the liquid storage unit,
A liquid circulation path for circulating the third liquid to a liquid switching unit,
An image forming apparatus having:
The liquid switching unit has a function of switching a liquid to be supplied so as to supply one of the first liquid and the third liquid when supplying the liquid to the liquid detection unit. An image forming apparatus wherein the detection output is corrected by switching.   The image forming apparatus according to claim 1, wherein an abnormality of the liquid detection unit is determined based on a change amount of the detection output of the liquid.   2. The image forming apparatus according to claim 1, wherein an abnormality of the liquid supply system is determined based on a change amount of the detection output of the liquid. The first liquid is supplied to the liquid detection unit, and the output of the light receiving element in a state where the light source is turned off is set as a first detection output,
An output of the light receiving element in a state where the light source is turned on at a predetermined light amount is defined as a second detection output,
The output of the light receiving element in a state where the light source is turned on at a light amount different from the light amount at the time of obtaining the second detection output as a third detection output,
The third liquid is supplied to the liquid detection unit, and when the light source is turned on at a predetermined light amount, the output of the light receiving element in a state where the second liquid is supplied is set as a fourth detection output, The output of the light receiving element in a state where the first liquid is further supplied to the liquid having obtained the fourth detection output is set as a fifth detection output,
The first detection output, the second detection output and the amount of change in the third detection output to determine that the liquid detection unit is abnormal,
From the change amount of one or both of the second detection output and the third detection output and the change amount of the fourth detection output, it is determined that the supply system of the third liquid is abnormal,
2. The image forming apparatus according to claim 1, wherein it is determined that the first liquid supply system is abnormal based on the amount of change between the fourth detection output and the fifth detection output. 3.   The method according to claim 4, wherein when the amount of change between the first detection result and the second detection result is equal to or less than a predetermined value, it is determined that the liquid passage portion is dirty, and the mode shifts to a dirt washing mode. Image forming device.