JP2015169882A - Conveyance device and image forming apparatus including conveyance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convey an amount required by reducing the influence of an error of the conveyed amount of an object to be conveyed generated in an initial drive of a conveyance device even when the conveyance device of the object to be conveyed is intermittently operated.SOLUTION: An error e of the conveyance amount of an object to be conveyed generated in an initial drive of conveyance means is obtained, and the conveyance means is made to convey the object to be conveyed more than a target conveyance amount by the obtained error of the conveyance amount. For example, the drive time of the conveyance means is set longer than the time required from the conveyance amount V per each target conveyance amount and unit time by the time corresponding to the error of the conveyance amount. When the object to be conveyed is not able to be conveyed by the target conveyance amount by the continuous driving of the conveyance means, the object to be conveyed is conveyed more than the target conveyance amount by the error of the conveyance amount corresponding to the driving frequency of the conveyance means at every driving on and after the second repetition.

Description

  The present invention relates to a conveyance device and an image forming apparatus including the conveyance device.

An electrophotographic image forming apparatus has a configuration in which toner is transported from a toner container and supplied to a developing device. In this configuration, it is important to replenish the target amount of toner with high accuracy so that the toner in the developing device does not wither or overflow.
In order to replenish the toner with high accuracy, a method has been proposed in which the rotational speed of the conveying device in the toner container is optimally controlled by adjusting the rotational speed and driving time of the motor of the driving source (for example, patents). Reference 1).

However, in the control so far, the rotation speed and driving time of the motor are controlled on the assumption that the amount of toner that can be replenished is constant with respect to the rotation speed of the toner conveyance device, and the toner conveyance device has started to rotate. The variation in toner replenishment amount at the time (hereinafter referred to as “driving initial stage”) was not taken into consideration.
In the case of a toner transport device that transports toner to the replenishment port of the developing device by rotating a transport member such as a screw or an agitator, and pushes the toner to the replenishment port with the transport force of the toner, the toner transport force at the initial stage of driving Therefore, the amount of toner that can be actually replenished is smaller than the target amount of toner.

Since the amount of toner that can be replenished with respect to the number of rotations of the toner conveying device is stable when the toner conveying device is driven for a certain period of time, the reduction in the toner replenishing amount at the initial stage of driving has been ignored as an error until now.
However, when the toner transport device is driven using a drive source used for other purposes or intermittently driven for quiet purposes, the toner transport device is driven to replenish the target toner amount. When the operation is repeated repeatedly, there is a problem in that the above-described error accumulates and the accurate toner amount cannot be supplied.

This is not limited to toner conveyance, but also applies to other powders, granules, gels, and the like.
The present invention has been made in view of the above-described problems, and reduces the influence of the conveyance amount error of the conveyed product that occurs in the initial driving of the conveyance device even when the conveyance device of the conveyed product is operated intermittently. The purpose is to transport the required amount.

  In order to achieve the above object, a transport apparatus according to the present invention includes a transport unit that transports a transported object, an error acquisition unit that acquires a transport amount error of the transported object that occurs at an early stage of driving the transport unit, and the transport The means includes control means for transporting the transported object more than the target transport amount by the transport amount error acquired by the error acquiring unit.

  According to the above configuration, even when the transport device for the transported object is operated intermittently, the effect of the transport amount error of the transported object that occurs in the initial stage of driving of the transport apparatus is reduced, and the target transported object is transported. Can do.

1 is a diagram illustrating a schematic configuration of an image forming apparatus including a toner transport device that is an embodiment of a transport device according to the present invention. FIG. FIG. 3 is a diagram schematically illustrating a configuration of toner supply from a toner container to a developing device. FIG. 6 is a diagram for describing a method for predicting a toner consumption amount based on image data. 3 is a diagram illustrating a configuration of a toner storage container 4 having a toner conveying unit. FIG. FIG. 6 is a diagram for describing a drive source of the toner conveyance device. FIG. 6 is a diagram illustrating a problem that occurs depending on the structure of the toner conveyance device. FIG. 5 is a diagram for explaining the influence of an error that occurs in the initial driving of the toner conveying unit. FIG. 10 is a diagram for explaining a method for solving an error problem in intermittent operation of the toner conveying device. 4 is a flowchart showing a flow of processing in the toner conveying device of the present invention. FIG. 10 is a diagram for explaining that an error due to a decrease in toner conveyance amount at the initial driving of the toner conveyance device varies depending on conditions around the conveyance device. 7 is an example of a table showing an error e of a toner conveyance amount determined by a remaining amount of toner container and temperature and humidity.

Hereinafter, embodiments for carrying out the present invention will be specifically described.
FIG. 1 illustrates a toner conveying apparatus (an apparatus that conveys toner that is an example of a conveyed product) that is an embodiment of a conveying apparatus of the present invention, and an image forming unit that forms an image on a recording medium such as paper. 1 is a diagram illustrating a schematic configuration of an image forming apparatus including the image forming apparatus.
The image forming apparatus shown in FIG. 1 is a so-called tandem type image forming apparatus. The configuration and operation of the image forming apparatus will be briefly described below.

  Around a photosensitive drum (hereinafter referred to as “drum”) 1 that is an image carrier, a charging device 2 for charging the surface of the drum 1 and a light beam for forming a latent image on a uniformly charged surface. An exposure device (not shown) that outputs a certain exposure 3, a developing device (embodiment of developing means) 5 that forms a toner image by attaching charged toner to the latent image on the surface of the drum 1, and a toner on the formed drum A transfer device 7 for transferring an image to a transfer target and a cleaning device 12 for removing residual toner on the drum 1 are sequentially arranged.

  In addition, a toner storage container 4 that stores replaceable toner, is connected to the developing device 5, and supplies the toner into the developing device 5 is disposed above the developing device 5. In this embodiment, the toner container 4 directly conveys the toner into the developing device 5. However, the toner container 4 may be configured to replenish the developing device 5 with a replenishment path provided in the main body of the image forming apparatus. In the tandem type electrophotographic image forming apparatus, monochromatic images such as black (Bk), magenta (M), cyan (C), and yellow (Y) are mainly formed on the surface of the drum 1. In FIG. 1, only the Bk image forming units are denoted by reference numerals, but the M, C, and Y image forming units have the same configuration.

In such a configuration, when image formation is performed by a negative positive method (a method in which the exposure portion potential is lowered and toner is attached), the drum 1 whose surface is uniformly negatively charged by the charging device 2 is exposed 3 As a result, an electrostatic latent image is formed on the surface of the drum 1, and toner is attached to the surface of the drum 1 by the developing device 5 to visualize the image.
The toner image is transferred from the surface of the drum 1 by the transfer device 7 including the transfer belt 13 and the residual toner component that has not been transferred from the drum 1 to the transfer belt 13 is removed from the surface of the drum 1 by the cleaning blade 11 of the cleaning device 12. Removed.

  The toner image transferred to the surface of the transfer belt 13 is transferred to the recording paper conveyed from the paper feed tray by applying a bias to the secondary transfer roller 8 at the secondary transfer portion. The residual toner component or the external additive component after the transfer is removed by the cleaning device 16. The toner image transferred onto the recording paper is welded onto the recording paper by the fixing device 9 and discharged from a paper discharge port (not shown).

  In the figure, reference numeral 15 denotes a sensor used to adjust the image density and alignment by measuring the amount of toner deposited on the intermediate transfer belt 13 and the position of each color, and is a combination of regular reflection and diffuse reflection. is there. Further, the cleaning blade 14 is in contact with the moving direction of the belt 13 so as to be a counter, and a metal cleaning facing roller 17 is provided so as to face the cleaning blade 14. The toner removed by the cleaning blade 14 is conveyed by a coil 18 or the like and stored in a waste toner storage unit (not shown).

FIG. 2 schematically shows a configuration for supplying toner to the developing device 5. The toner container 4 is filled with toner. The developing device 5 includes a storage unit 19 that temporarily stores toner. The developing device 5 consumes the toner in the storage unit 19 to form a toner image on the surface of the drum 1.
The developing device 5 and the toner container 4 are connected by a toner replenishing port 20, and when the toner in the developing device 5 becomes low, the toner conveying means provided in the toner container 4 is operated to supply the toner. .

Here, a configuration in which toner is directly conveyed to the developing device 5 is shown, but a configuration in which a replenishment path is provided in the main body of the image forming apparatus and toner is replenished to the developing device 5 may be used (hereinafter, the toner is directly supplied to the developing device). This will be described in the configuration for transport.)
The amount of toner in the developing device 5 is detected by using toner detection means 21 provided inside or outside the developing device 5. The toner detecting means 21 may be a method of measuring the draft level by a light transmission type sensor composed of a light emitting part and a light receiving part.

  If the toner contains a magnetic material, a method of detecting the amount of toner with a density sensor that detects the strength of the magnetic field may be used. The amount of toner to be supplied is the amount of toner consumed by the developing device 5. The amount of toner consumed by the developing device 5 is obtained by the toner detection unit 21 or, if the toner detection unit 21 does not have the accuracy, it may be predicted based on image data at the time of image formation. .

  FIG. 3 is a diagram for explaining a method of predicting toner consumption based on image data. Hereinafter, a method of predicting the amount of toner consumed by the developing device 5 will be described with reference to FIG. Note that this is one method used when the toner amount detection accuracy by the toner detection means 21 is insufficient.

  First, data of 5 pixels in the main scanning direction and 5 pixels in the sub-scanning direction are extracted from the image data, and 5 × 5 matrix data centering on the pixel of interest A is generated. At this time, γ conversion of density data is performed in advance in accordance with the characteristics of the exposure means (LED or the like). A weighting coefficient is set for each of reference pixels B to I adjacent to one pixel, including reference pixel A, and reference pixels J to Y adjacent to two pixels, and the total light amount of A is calculated. As the weighting coefficient, a common value is used for reference pixels that are symmetrical with respect to the target pixel. The light quantity of A is obtained by the following formula.

“A light quantity” = A × main + (C + G) × ref1_1 + (E + I) × ref1_2 + (B + D + F + H) × ref1_3 + (L + T) × ref2_1 + (P + X ) × ref2_2 + (K + M + S + U) × ref2_3 + (O + Q + W + Y) × ref2_4 + (J + N + R + V) × ref2_5
The amount of toner developed is proportional to the amount of light that exposes the photoconductor, but is saturated at a certain light amount level (upper limit), and no more is developed. Therefore, saturation processing is performed.
If “light quantity of A” ≤ upper limit value → Conversion value of toner consumption (X) = “light quantity of A”
If "A light quantity"> upper limit value → Toner consumption conversion value (X) = upper limit value

Furthermore, a certain amount of offset value is subtracted in order to bring the converted value of the toner consumption calculated from “A light quantity” closer to the amount of toner actually developed.
That is, “converted value of toner consumption per pixel =“ light quantity of A ”−offset value”. If the calculation result is negative, the result is 0.
The above processing is performed for all the pixels in one page to be printed, and the total of converted values of toner consumption for one page is calculated. When the peripheral pixel is outside the image area, the peripheral pixel is treated as a pixel with zero light quantity.

FIG. 4 is a view for explaining the configuration of the toner container 4 having toner conveying means as one component of the toner conveying device 50. 4A is a cross-sectional view of the toner container 4 as viewed from the front, and FIG. 4B is a cross-sectional view as viewed from the side.
In the toner container 4, a toner agitating means 52 such as an agitator made of a flexible material made of, for example, a PET film, which is fixed to the rotating shaft 53, and a toner conveying means made up of a screw or a coil, etc. 51 is provided.

  The toner agitating means 52 serves to supply the toner in the direction of the toner conveying means 51 while ensuring fluidity of the toner in the toner container 4 by rotating. In order to use up the toner in the toner container 4, it is desirable that the cross section of the container is formed in an arc shape in accordance with the rotational movement of the toner stirring means 52. The toner transport unit 51 plays a role of transporting toner in the direction of the arrow 55 by rotating. The toner is transported to the toner replenishing port 54 and replenished to the developing device 5 by rotating the toner agitating unit 52 and the toner transporting unit 51 by a driving source (not shown) installed in the main body of the image forming apparatus.

  The toner conveying means 51 controls the toner conveying amount by the pitch diameter, size, rotational speed, and the like of the rotating member. When toner shortage is confirmed by the toner detecting means 21 installed in the developing device shown in FIG. When toner filling is confirmed by the toner detection means 21, the rotation operation is stopped and the toner amount in the developing device is stabilized. The toner conveyance amount can be controlled by the rotation speed or the rotation time of the rotating member of the toner conveyance means 51. For example, the driving time is set in accordance with the change in toner fluidity depending on the environment such as temperature and humidity. Controls such as changing are also possible.

FIG. 5 is a diagram for explaining a drive source of the toner conveyance device 50. FIG. 5 is an example schematically showing how the power is supplied to the toner conveying device 50.
In order to rotate the toner agitating means 52 and the toner conveying means 51 shown in FIG. 4, it is necessary to supply power to the toner conveying apparatus 50 from a driving source such as a motor.

FIG. 5 shows a configuration in which a Bk photoconductor motor 62 that is a drive source of the Bk drum 1 is connected to the toner conveying device 50 of each color. In this configuration, the toner transport device 50 for each color and the Bk photoconductor motor 62 can be controlled to be connected / disconnected by a known method such as the clutch 61, and the toner transport device 50 can be driven. As a result, the toner is replenished in parallel with the image forming operation, so that the toner is replenished intermittently. However, power components can be reduced correspondingly, leading to cost reduction.
The color photoconductor motor 63 is a driving source for a color (C, M, and Y) drum, and the transfer motor 64 is a motor that drives the transfer belt 13, but in this example, the toner conveying device 50 is driven. Since is not involved, detailed description is omitted.

FIG. 6 is a diagram illustrating a problem that occurs depending on the structure of the toner conveying device. In the case of the toner conveying device 50 as shown in FIG. 4, since the toner replenishing port 54 is arranged on one side of the container, as shown in FIG. Since the conveying force is weak, the amount of toner that can be actually replenished is smaller than the target amount of toner.
On the other hand, as shown in FIG. 6B, the amount of toner that moves in the toner transport direction (in the direction of the arrow) increases after the toner transport means 51 is driven and a predetermined time elapses. Will also increase.

Therefore, since there is a difference in the replenishment amount after a certain period of time from the beginning of driving, the replenishment amount is not proportional to time.
As a result, in the simple control in which the rotation speed of the toner conveying means 51 is made constant and the toner is simply replenished by starting / stopping driving, an error occurs in which the amount of toner that can be replenished is smaller than the target toner amount.

FIG. 7 is a diagram for explaining the influence of an error that occurs in the early stage of driving the toner conveying means.
FIG. 7A is a diagram illustrating a case where the target toner supply amount is supplied once. When the toner conveyance speed is V [g / sec] after the toner conveyance means 51 is started to drive (the drive source is OFF → ON) and a predetermined time has elapsed, the toner conveyance speed becomes V immediately after the drive source is turned on. In the meantime, the conveyance speed is lower than V. For this reason, if the target toner replenishment amount is simply divided by the toner conveyance speed V to determine the drive time t, the actual conveyance amount will be less than the target value, and that amount will be the error e. However, when the target toner replenishment is completed by one toner conveyance and the error is small compared to the target toner replenishment amount, this error can be ignored.

  On the other hand, FIG. 7B is a diagram illustrating a case where the toner transport unit 51 is intermittently driven and toner supply is not completed once, but is performed in a plurality of times. As described above, the intermittent operation of the toner conveying device 50 is to share the driving source of the toner conveying device with the driving source of another device (for example, a photosensitive drum driving motor) in order to reduce the number of parts. This is necessary when it is necessary to limit the continuous operation for a long time for the purpose of silence.

  In the case of intermittent driving, as shown in the figure, since it is considered that the start and stop of driving are repeated a plurality of times in order to supply the same amount of toner as in the case of (A), the driving time per time is short. For this reason, the error e due to the decrease in the toner conveyance amount at the initial stage of driving becomes a size that cannot be ignored compared with the conveyance amount for one time. Further, since an error e occurs every time driving is started, the errors are accumulated and cannot be ignored.

FIG. 8 is a diagram for explaining a method for solving the error problem of the intermittent operation of the toner conveying device shown in FIG. 7B adopted in this embodiment.
In this embodiment, the toner replenishment amount error e at the initial stage of driving is added to the target value of the toner replenishment amount so that the error e of the toner replenishment amount occurring at the initial stage of driving of the toner conveying device does not accumulate. The driving time of the toner conveying device is extended so as to compensate for the error e. Further, when the toner conveying device operates intermittently, the driving time of the toner conveying device after resumption is extended by the amount of toner replenishment amount error e when resuming driving. Note that the value of the error e is determined by experiments at the time of designing or manufacturing the apparatus, and stored in advance in the toner conveying device 50 or a control unit of an image forming apparatus including the toner conveying device 50.

Specifically, assuming that the target value of the toner replenishment amount is S _target [g], S _target [g] is obtained by the following formula 1 based on the toner amount C [g] consumed by the developing device 5. . Here, k is a coefficient for correcting the toner replenishment amount with respect to the toner consumption amount C.
S _target = k × C + e (Formula 1)
Here, k × C corresponds to the actual toner consumption value, and e is a term to be added to convey the toner by an amount corresponding to the error of the toner replenishment amount at the initial driving of the toner conveying device 50.

Further, if the target driving time of the m-th toner conveying device 50 for conveying the toner of S _target [g] is t _target (m),
t _target (1) = S _target / V
= K × C / V + e / V (Formula 2)
It is. Since the error e is corrected when determining S _target , S _target may be simply _divided by the transport amount V per unit time. E / V is a drive time to be added corresponding to the error e.

Here, in the case of intermittent driving, it is not always possible to continuously drive the toner conveying device 50 by t _target (1). Therefore, the time during which the toner conveying device 50 is actually continuously driven in the m-th driving is defined as t _real (m) [sec]. Then, the estimated value S _real (m) [g] of the toner amount actually replenished by the m-th drive is
S _real (m) = V × t _real (m) −e (Equation 3)
It becomes. Here too, −e is a term for adjusting the error of the toner replenishment amount at the initial driving of the toner conveying device 50.

From Equation 1 and Equation 3, the target value S _next (1) of the toner replenishment amount at the first drive stop time is
S _next (1) = S _target -S _real (1)
= K × C−V × t _real (1) + 2e (Formula 4)
It becomes. In addition, t _target (m) (m ≧ 2) in the second and subsequent driving operations is
t _target (m) = S _next (m−1) / V (Formula 5)
It is. Until t _target (m) can be driven, t _target (m + 1) is obtained by using t _real (m) at that time each time driving is performed, and the next driving is performed. When t _target (m) can be driven, it is only necessary that the toner transport of S _target [g] is completed.

Here, when m ≧ 2,
S _next (m) = S _next (m−1) −S _real (m)
= S _target -ΣS _real (k)
= S _target −V × Σt _real (k) + me
= K × C−V × Σt _real (k) + (m + 1) e (Expression 6)
(Where Σ is the sum of k = 1 to m)
It is. Therefore, substituting Equation 6 into Equation 5, when m ≧ 2,
t _target (m) = k × C / V−Σt _real (k) + me / V (Expression 7)
It becomes.

This term of me / V corresponds to the drive time added to the time when there is no error corresponding to the error e accumulated m times from the start of the m-th drive.
Due to the me / V term, toner replenishment is intermittently performed, and even if the toner transport amount drop (error generation) at the beginning of driving is repeated twice or three times, an error e of the toner transport amount is accumulated. Can be prevented. That is, in each of the second and subsequent driving operations, the toner transport amount error e is accumulated by transporting the toner more than the target transport amount by the transport amount error corresponding to the number of times the toner transport unit is driven. Can be prevented.

  Next, the flow of toner replenishment processing in the toner transport device 50 will be described. FIG. 9 is a flowchart showing the flow of processing in the toner conveying apparatus of the present invention. The processing in each step is performed based on a predetermined program by a CPU (not shown) of an image forming apparatus provided with the toner conveying device. This process starts when the power of the image forming apparatus is turned on.

In the process of FIG. 9, first, the CPU detects the toner remaining amount in the developing device 5 periodically (for example, at intervals of 5 minutes) by the toner detection unit 21 (S1). When the remaining amount of toner in the developing device 5 is equal to or greater than the predetermined value (Y in S2), the process returns to step S1 and continues to detect the remaining amount of toner.
On the other hand, when the remaining amount of toner in the developing device 5 is less than the predetermined value (N in S2), the CPU acquires an error e at the initial stage of toner conveyance (S3). That is, the CPU functions as an error acquisition unit. As will be described later, the toner transport amount error e is a specific value defined for each ambient condition (remaining amount of toner container, ambient absolute humidity) measured at the design or manufacturing stage.

Next, the CPU calculates a target value S _target of the toner replenishment amount using the above formula 1 (S4).
Here, m = 1 is set (S5), and the CPU calculates the toner transport time t _target (m), here t _target (1) using Formula 2 or Formula 5 (S6).

Next, the CPU starts driving the toner conveying means 51 of the toner conveying device 50 in accordance with the start of driving of a driving motor of another device (for example, a photosensitive drum) (S7). The start time at this time is t _start . Then, the CPU measures the time when the driving motor of the other apparatus is stopped and the driving of the toner conveying means of the toner conveying apparatus is stopped in conjunction with the driving motor (S8). The time at this time is set to t _stop , and the actual continuous conveyance time t _real (m) (= t _stop −t _start ) is calculated (S9).

When t _real (m) obtained in S9 is shorter than t _target (m) obtained in S6 (N in S10), the target toner replenishment amount S _target is not completely replenished, and the toner conveying means 51 is driven. It means that it was interrupted on the way. That is, since it is considered that the operation is interrupted due to the intermittent operation, the CPU calculates a target value S _next (m) for the _next toner replenishment amount using Equation 3, Equation 4, or Equation 6 (S11).

Next, the CPU determines whether or not the next toner replenishment amount target value S _next (m) is equal to or less than the minimum replenishable toner amount S _min [g] (S12). When S _next (m) is larger than the minimum replenishable toner amount S _min (N in S12), the value of m is increased by 1 (S13), and the process returns to S6 to set a new toner transport time t _target (m). Calculate (S6) and repeat the following process.
On the other hand, if S _next (m) is less than or equal to the minimum replenishable toner amount S _min in step S12 (Y in S12), S _next (m) is treated as an error that can be ignored, and a series of toner replenishment processing ends. . Then, returning to step S1, the CPU detects the remaining amount of toner in the developing device, and confirms whether or not the remaining amount of toner in the developing device actually exceeds a predetermined value.

Through the above processing, toner replenishment that corrects the error e of the toner replenishment amount that occurs in the initial stage of driving as described with reference to FIG. 8 is possible. Thus, even when the toner conveying means 51 is driven intermittently, it is possible to reduce the influence of the error in the toner replenishment amount and replenish the necessary amount of toner.
The processing considering the error e is steps S4 and S11. However, if the error e is not considered here, an error of m × e occurs in the total toner replenishment amount by m driving, and the error cannot be ignored. Become. By obtaining S _target and S _next (m) in consideration of the error e in steps S4 and S11, the occurrence of this error can be prevented.

For this reason, even if the toner conveying device is operated intermittently, the targeted toner amount can be replenished with high accuracy.
As a result, toner replenishment to the developing device is not delayed, and the frequency of stopping the image forming apparatus to recover the delay in replenishment is reduced, so that a reduction in productivity can be prevented. Further, since the drive source of the toner conveying device can be shared with the drive source of other devices, the drive sources can be reduced, and the cost of the entire image forming apparatus can be reduced.

Next, a procedure for setting the error e will be described.
FIG. 10 is a diagram for explaining that the error of the toner replenishment amount in the initial driving stage of the toner conveying device varies depending on the conditions (humidity) around the conveying device.
As shown in FIG. 10, the error e of the toner replenishment amount due to the decrease in the toner conveyance amount that occurs in the initial driving of the toner conveyance device 50 varies depending on the toner state.
One of the fluctuation factors is the remaining amount of toner in the toner container. This is because if the remaining amount of toner is large, the toner transport amount per unit time is quickly stabilized, and conversely if the remaining amount of toner is small, the toner transport amount per unit time is not stable.

Therefore, when the toner container is replaced with a new one, the error e of the toner replenishment amount is small, and when the replacement time is near, the error e of the toner replenishment amount is large.
Next, temperature and humidity are cited as fluctuation factors. The toner has low fluidity in a high temperature and high humidity environment, and high fluidity in a low temperature and low humidity environment. Accordingly, the error e of the toner replenishment amount is large in the high temperature and high humidity environment, and the error e of the toner replenishment amount is small in the low temperature and low humidity environment.

In FIG. 10, the upper row shows the case where the remaining amount of the toner container is “medium” and the temperature / humidity is “normal”, and the middle row shows the case where the remaining amount of the toner container is “small” and the temperature / humidity is “normal”. The magnitude of the error is shown. From this, it can be seen that if the temperature and humidity are the same, the error becomes larger when the remaining amount of the toner container is smaller.
The lower row shows the case where the remaining amount of the toner container is “small” and the temperature / humidity is “high temperature and humidity”. When comparing the middle and lower rows, if the remaining amount of the toner container is the same, It can be seen that the error becomes larger.

In the present invention, the error e of the toner transport amount is measured at the stage of designing or manufacturing the toner transport device 50 or an image forming apparatus including the toner transport device 50 for each remaining amount of toner container and temperature / humidity. This value is stored in advance as a table in the toner conveying device 50 or the memory of the image forming apparatus. FIG. 11 shows an example of the table.
The toner container remaining amount r [g] is obtained by accumulating the actual toner replenishment amount S _real (m) (m = 1, 2,...) Calculated by Expression 3 using a recording unit such as a nonvolatile memory. It is obtained by subtracting from the filling amount of the toner container.
For temperature and humidity, an absolute humidity h [g / cm ² ], which is the amount of water per unit volume that can be calculated by a known calculation formula, is obtained.

For the toner container remaining amount r [g], a higher threshold value Rh and a lower threshold value Rl are set, and “large (Rh <r)”, “medium (Rl ≦ r ≦ Rh)”, and “small” (r) <Rl) ”. For the absolute humidity h [g / cm ² ], the higher threshold value Hh and the lower threshold value H1 are set to “high temperature and high humidity (Hh <r)”, “normal (Hl ≦ h ≦ Hh)”, and “low temperature and low humidity”. (H <Hl) ”.

For each of the conditions classified as described above, the toner transport amount error e is measured at the design stage, and a matrix like the table in FIG. 11 is created in advance.
In this table, if the toner container remaining amount r is the same rank, the error increases as the temperature and humidity increase.
That is, e1 <e2 <e3, e4 <e5 <e6, and e7 <e8 <e9 hold.

Further, if the temperature and humidity are the same rank, the error increases as the toner container remaining amount r decreases.
That is, e1 <e4 <e7, e2 <e5 <e8, and e3 <e6 <e9 hold.
Here, the remaining amount of the toner container and the temperature / humidity are set to three levels, but the level may be increased / decreased according to the conveyance accuracy of the remaining toner calculation unit, the temperature / humidity detection unit, and the toner conveyance device. Good.

In step S3 of the flowchart of FIG. 9 described above, the CPU stores this table from the toner container remaining amount r and the humidity h detected by temperature / humidity detection means (not shown) such as a sensor attached to the image forming apparatus main body. Referring to, error e is acquired.
As described above, if the error e is acquired based on the remaining amount of the conveyed product in the container and the humidity around the conveying device, the influence of the error e can be more accurately removed.

Although the description of the embodiment has been completed above, the present invention is not limited to the above-described embodiment. It is possible to change a specific configuration of the apparatus, a specific processing procedure, a mathematical expression used for calculating a target value, and the like within a range that does not impair the gist of the present invention.
For example, in the description of the above-described embodiment, the case where the conveyed product is toner that is a developer is taken as an example, but other powders, granules, and gels may be applied in addition to the toner. In addition, the transport apparatus of the present invention can be mounted on various apparatuses other than the image forming apparatus or used in combination with various apparatuses, depending on the type of transport object.

In the above embodiment, the error e is obtained by referring to the table. However, for example, the error e may be obtained by calculation from the time from the start of driving until the toner conveyance speed reaches the steady state V [g / sec]. Good.
In addition, the correction of the toner replenishment amount error described above may not be performed uniformly, but may be performed after determining whether to perform correction. For example, on the basis of variations in the transport amount that can be transported by the toner transport unit per unit time, correction is not performed if the variation is within the range, and correction is performed if the variation is exceeded.

This variation is determined by the hardware configuration of the toner conveying unit, and is measured in a design stage in a state where the toner conveying unit is continuously driven and the influence of an error in the initial conveyance can be ignored. Even when intermittent driving is performed, if the sum of the effects of errors at the initial stage of conveyance is less than the variation that occurs during the continuous driving, even if correction is performed, it does not contribute much to the improvement of the conveyance amount accuracy. Therefore, correction is not performed.
Furthermore, it is needless to say that the embodiments and operation configurations described above can be arbitrarily combined and implemented as long as they do not contradict each other.

1: Photosensitive drum, 2: Charging device, 4: Toner container, 5: Developing device, 13: Transfer belt, 19: Container, 20: Toner replenishing port, 21: Toner detection means, 50: Toner transport device, 51: Toner conveying means, 52: Toner agitating means, 53: Rotating shaft, 54: Toner replenishing port, 61: Clutch, 62: Bk photoconductor motor, 63: Color photoconductor motor, 64: Transfer motor

JP 2011-090271 A

Claims (7)

A conveying means for conveying a conveyed item;
Error acquisition means for acquiring a transport amount error of the transported object that occurs in the initial driving of the transport means;
A transport apparatus comprising: the transport unit including a control unit configured to transport the transported object more than a target transport amount by an error of the transport amount acquired by the error acquisition unit. It is a conveying apparatus of Claim 1, Comprising:
The control means is means for making the drive time of the transport means longer by a time corresponding to the transport amount error than a time obtained from the target transport amount and a transport amount per unit time. Conveying device to do. It is a conveying apparatus of Claim 1 or 2, Comprising:
The transported object is accommodated in a container and transported from the inside of the container to the outside of the container,
The said error acquisition means acquires the said conveyance amount error based on the residual amount of the conveyed product in a container, and the temperature and humidity around the said conveying apparatus, The conveying apparatus characterized by the above-mentioned. It is a conveyance apparatus as described in any one of Claims 1 thru | or 3, Comprising:
The control means transports according to the number of times of driving of the transporting means in the second and subsequent driving when the transported object cannot be transported by a target transport amount by continuous driving of the transporting means. A transport apparatus that transports the transported object more than a target transport amount by an amount error. It is a conveying apparatus as described in any one of Claims 1 thru | or 4, Comprising:
The conveyed product is a developer,
The transporting apparatus, wherein the transporting means is means for supplying the developer from a developer container to the developing means. A transport apparatus according to claim 5;
Image forming means for forming an image on a recording medium;
A developing unit that develops the image formed by the image forming unit using a developer;
An image forming apparatus, wherein a developer is supplied to the developing means by the conveying device. The image forming apparatus according to claim 6,
An image forming apparatus, wherein a conveying unit included in the conveying device and the image forming unit are driven using a common drive source.