JP4803647B2 - Image forming apparatus using process cartridge - Google Patents

Description

The present invention relates to an electrophotographic image forming apparatus using an attachable / detachable process cartridge having a color transfer section and a high-voltage power supply section (an MFP (composite MFP, a combination of functions of a printer, a copying machine, a copying / fax printer, etc.). ) machines, etc.) relates to, and more particularly, to an image forming apparatus using the profile processes cartridge with management functions needed to optimize the color image output.

Conventionally, in an electrophotographic image forming apparatus (printer, copier, facsimile machine, etc.), a photosensitive member and a developer used in an image forming process to improve production efficiency and facilitate maintenance. A method is adopted in which the process cartridge, transfer part, and the like are detachable process cartridges (for example, see Patent Documents 1 to 3 below).
When the transfer unit is unitized as a process cartridge, in order to obtain a required transfer property, a target value of a transfer current corresponding to a difference in characteristics or the like of the process cartridge is set, and control for flowing the target current is performed. In Patent Document 3 below, the resistance value of the belt is obtained from the applied current value to the transfer belt and the actually applied voltage value, and the current for obtaining optimum transfer conditions is set based on the actually measured resistance value. Yes.
JP 2003-195690 A JP 2002-49206 A JP 2003-57966 A

By the way, the following color cartridge has been proposed as a prior art in which the transfer portion is a process cartridge (hereinafter referred to as a “prior example”). That is, this prior example is a so-called tandem type color image forming apparatus (usually an image formed for each color component constituting a color composed of cyan (C), yellow (Y), magenta (M), and black (K). And a first image carrier (for example, a photoconductor) that holds the toner image, and is applied to an intermediate transfer member (for example, a transfer belt) to form a color image on a transfer sheet. In addition to the primary transfer unit for color and the secondary transfer unit for color composite image, a high-voltage power supply unit for driving the transfer unit is integrated (see the description regarding FIG. 5 below). Note that the transfer unit (belt unit) of Patent Document 3 exemplified above applies a transfer belt wound around a pair of rollers, a solenoid and a lever for bringing the transfer belt into contact with and separating from the photoreceptor, and a transfer bias. It consists of a contact plate that neutralizes the charge on the bias roller and transfer belt, and the high-voltage power supply is provided on the apparatus main body side.
The high-voltage power supply unit in the preceding example detects the primary transfer output current and output voltage during process control of the image forming apparatus in order to prevent primary transfer failure and abnormal discharge caused by fluctuations in primary transfer resistance. Then, the resistance of the primary transfer is detected, and the control according to the process specification for determining the target value of the output current of the primary transfer from the obtained resistance value is performed. The primary transfer resistance is related to the intermediate transfer belt and the primary transfer roller. The variation that occurs in the resistance is caused by the variation in the respective resistance values, and has a side that the accumulated resistance tolerance of the two combined resistance values increases the variation. In the primary transfer bias of constant current control, if the resistance value is small, the output voltage is small with respect to the target and causes a transfer failure. If the resistance value is large, the output voltage is large with respect to the target and abnormal discharge occurs. It will cause such troubles.

However, this prior example has the following problems. That is, the output voltage of the primary transfer output is detected as an analog signal by the high-voltage power supply unit, and this analog signal is fed back to the main control unit of the image forming apparatus. Resistance (which is obtained based on the output voltage and output current at the time of transfer) cannot be detected, and erroneous detection or the like may occur. In addition, since voltage detection is performed for the four color components, the circuit configuration of the high-voltage power supply substrate becomes complicated and the cost increases, and as a result, it is unsuitable for process cartridges that require a simple configuration and low cost. Furthermore, since the voltage detection of the primary transfer output of the four color components is performed during the predetermined process control performed by the image forming apparatus, the process control time increases, which impedes rapid processing.
The present invention uses the above-described process cartridge having a configuration in which a high-voltage power supply unit for driving the transfer unit is integrated in addition to a primary transfer unit for each color component and a secondary transfer unit for a color composite image. In view of the problems in the prior examples, the present invention has been made to solve this problem. The problem to be solved is that, as in the previous examples, the high-voltage power supply unit detects the output voltage of the primary transfer, and the detected analog signal is Without using the approach of transmitting to the main body, the means to obtain the resistance value of the transfer part can be configured more simply and at low cost, and it is possible to perform transfer by a control method that can shorten the process control time It is an object of the present invention to provide a process cartridge that realizes a function that enables an appropriate image output by an image forming apparatus using the process cartridge.

According to the first aspect of the present invention, a transfer roller for each color provided corresponding to the first image carrier is provided in order to transfer the image carried on each first image carrier for each color to the second image carrier. a primary transfer unit that gives a transfer bias to the second image bearing member via the responsible lifting image on the second image bearing member is transferred to the third image bearing member, a second image bearing member via the transcription roller A secondary transfer unit that applies a transfer bias to the image forming apparatus, a high-voltage power supply unit that applies a transfer bias to the primary transfer unit and the secondary transfer unit, a transfer roller for each color of the primary transfer unit, and the second image carrier A plurality of IC chips that are attached to the body and read information on resistance values of the transfer rollers for the respective colors of the primary transfer unit and the second image carrier, and non-contacts corresponding to the respective IC chips a plurality of IC tags consisting of the formulas communication means, a process cartridge having a A tag reader / writer device for the plurality of IC tags, a transfer roller for each color of the primary transfer unit obtained from the plurality of IC tags via the tag reader / writer device, and the first image forming apparatus. The combined resistance value of the primary transfer unit is calculated from the resistance value information of each of the two image carriers, and if the calculated combined resistance value is outside a predetermined allowable range, the high-voltage power supply unit is not driven. A control unit that displays a warning on the operation display unit of the image forming apparatus and drives the high-voltage power source unit according to the calculated combined resistance value when the calculated combined resistance value falls within the allowable range. An image forming apparatus.
In the invention according to claim 2, when the calculated combined resistance value falls within the allowable range, the control unit determines which of a plurality of predetermined ranges the combined resistance value is, and the combined resistance value 2. The image forming apparatus according to claim 1, wherein a PWM signal corresponding to the range in which is included is output to the high-voltage power supply unit.
According to a third aspect of the present invention, when the calculated combined resistance value is out of a predetermined allowable range, the control unit outputs a PWM signal fixed to 0% from the control unit to the high voltage power supply unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

According to the present invention, the composition of the primary transfer portion is synthesized from the information on the resistance values of the transfer roller for each color of the primary transfer portion and the second image carrier obtained from the plurality of IC tags via the tag reader / writer device. the resistance value calculated, without driving of the high-voltage power supply unit when the combined resistance value the operation out of the allowable range predetermined display a warning on the operation display unit of the image forming apparatus by a row Ukoto, transfer failure and Abnormal discharge can be prevented and the state of each color can be easily recognized.

Hereinafter, a process cartridge used in an electrophotographic image forming process according to an embodiment of the present invention and an image forming apparatus using the process cartridge will be described. In this embodiment, as the first image carrier, four photosensitive drums each carrying an image of each color component of cyan (C), yellow (Y), magenta (M), and black (K) are used. As an example of the second image carrier, a color copying machine that forms a color image by a so-called tandem method using a transfer belt that performs an intermediate transfer is shown.
FIG. 1 is a diagram schematically showing a configuration of a color copying machine according to the present embodiment. An image forming engine unit having a process cartridge that can be attached to and detached from the apparatus is shown in more detail in FIG.
The color copying machine shown in FIG. 1 photoelectrically converts reflected light from an exposed copy original and performs signal processing of the read original image, and PM and PWM modulation are applied by image data to control light emission. The writing unit 2 irradiates the photosensitive surface with the beam light from the laser light source, and the photosensitive drum 3 that irradiates the photosensitive surface with the laser beam from the writing unit 2 and forms an electrostatic latent image. Further, around the photosensitive drum 3, a charging unit 4 that uniformly charges the photosensitive surface, a developing unit 5 that attaches toner to the photosensitive drum 3 that formed a latent image, and a photosensitive drum 3. And a transfer unit 6 for transferring the toner image onto the transfer paper (performed via an intermediate transfer belt). Here, because of the tandem method, development and image formation around the photosensitive drum 3 can be performed independently for each color component of cyan (C), yellow (Y), magenta (M), and black (K). Further, the color components are combined in the transfer process.
In addition, a paper feed tray is provided in the main body 7 (single-sided machine) and the paper feed bank 8, and a manual paper feed tray 9 is provided in the main body. Further, the image forming apparatus includes a belt fixing unit 11, a fixing roller 12, and a pressure roller 13 that apply temperature and pressure to the image-formed transfer paper sent by the conveying unit and fuse the toner onto the paper.

FIG. 2 shows a main configuration of an image forming engine having a process cartridge.
Since a tandem image forming engine is configured, toner images of the respective colors are formed on the photosensitive drums 3C, 3Y, 3M, and 3K for four colors that are color components. Therefore, around the photosensitive drums 3C, 3Y, 3M, and 3K, charging units 4C, 4Y, 4M, and 4K (to uniformly charge the photosensitive surface before optical writing) and developing units 5C, 5Y, and 5M, respectively. , 5K (developing the electrostatic latent image generated by optical writing with toner) and cleaning units 15C, 15Y, 15M, 15K (cleaning untransferred toner on the photosensitive drum) and the like. . Each image forming unit has no fundamental difference other than the toner used.
In this example, the toner image formed on each photosensitive drum is temporarily transferred (primary transfer) to the intermediate transfer belt 19, and then the image on the intermediate transfer belt 19 is further transferred (secondary transfer) to the transfer paper. An image is formed on the transfer paper by transferring twice. Further, since image formation is performed by one sheet passing, the intermediate transfer belt 19 passes through the photosensitive drums 3C, 3Y, 3M, and 3K arranged at a predetermined interval from the upstream side to the downstream side of the moving intermediate transfer belt 19. The image transferred above is superimposed on a belt to form a color image, and then copied onto a transfer sheet.

In this embodiment, the transfer unit that performs the transfer operation described above is detachably attached to the apparatus main body as a process cartridge. A portion indicated by a broken line in FIG. The process cartridge 22 includes a primary transfer roller 16C, 16Y, 16M, and 16K, a secondary transfer roller 17, a belt cleaning unit 20, an intermediate transfer belt 19, and a high-voltage power supply substrate 21 in an integrated manner. .
The toner images on the photosensitive drums 3C, 3Y, 3M, and 3K formed by the image forming units for four colors are sequentially primary on the intermediate transfer belt 19 by the primary transfer rollers 16C, 16Y, 16M, and 16K. Transcribed. Further, the color-combined toner image on the intermediate transfer belt 19 that has been primarily transferred is secondarily transferred onto the transfer paper by the secondary transfer roller 17 and the secondary transfer counter roller 18 that opposes the toner image. The toner remaining as untransferred toner on the intermediate transfer belt 19 is removed by the belt cleaning unit 20.
The high-voltage power supply substrate 21 applies a transfer bias to the intermediate transfer belt 19 via each primary transfer roller in order to primarily transfer the toner image on each photosensitive drum to the intermediate transfer belt 19, and the intermediate transfer belt In order to secondarily transfer the toner image on the transfer sheet 19 to a transfer sheet, a high voltage power supply unit that applies a transfer bias to the intermediate transfer belt 19 via the secondary transfer roller 17 is provided.
Here, in the primary transfer, the photosensitive drums 3C, 3Y, 3M, and 16M are applied to the primary transfer rollers 16C, 16Y, 16M, and 16K by applying a positive polarity bias that is opposite to the toner image (−polarity). The toner image formed on 3K is drawn from the inside of the intermediate transfer belt 19 and transferred onto the intermediate belt 19.
The secondary transfer is performed by an extrusion bias using the secondary transfer roller 17, the secondary transfer counter roller 18 and the intermediate transfer belt 19. By applying a negative polarity toner image transferred onto the intermediate transfer belt 19 to the secondary transfer roller 17 having the same polarity as the toner, the toner is pushed out from the inner side of the intermediate transfer belt 19 and pushed out. The toner is transferred by receiving the transferred toner on a transfer paper.

The high-voltage power supply unit of the high-voltage power supply substrate 21 applies a transfer bias to the intermediate transfer belt 19 through the primary transfer rollers 16C, 16Y, 16M, and 16K for each color during primary transfer. , 16Y, 16M, 16K and the intermediate transfer belt 19 each have a specific resistance value. In order to obtain an appropriate transfer bias, the transfer output corresponding to the resistance value is obtained after knowing these resistance values. It is necessary to set a target current value and output a target current value according to the setting.
In order to know the resistance of the primary transfer portion, the high voltage power supply portion of the high voltage power supply substrate 21 of the previous example is based on a system in which a circuit for detecting this resistance is provided in the power supply portion.
FIG. 7 shows a hardware configuration of a control system that applies a transfer bias of the primary transfer unit by a high-voltage power supply unit using the resistance detection method of the preceding example.
The transfer bias control system shown in FIG. 7 is roughly composed of a high voltage power supply unit 30 ′ and a main body control unit 50 ′.
The high voltage power supply unit 30 ′ is provided with a booster circuit by a drive transformer 32 ′ and a drive control unit 31 ′ for driving the circuit in order to perform a high voltage primary transfer output. The primary transfer output (output to the primary transfer roller) is a current-based constant current control method, and the primary transfer output current is detected by the detection circuit 33 ′ in the high-voltage power supply unit and fed back to the drive control unit 31 ′. ing. In the drive control unit 31 ′, the PWM signal from the main body control unit 50 ′ is received as a control signal, and the received primary PWM output current fed back from the output side with the received PWM signal as the target value of the primary transfer output. This output current control is performed by comparing with the detected value.

At this time, the output voltage of the primary transfer is detected by the detection circuit 34 and fed back to the main body control unit 50 ′ as a primary transfer output feedback voltage (indicating a value proportional to the resistance of the primary transfer unit). Yes.
The main body control unit 50 ′ includes a CPU, a ROM that stores programs and data executed by the CPU, a RAM that the CPU uses as a work area, and the like, according to various programs and data for controlling the entire apparatus stored in the ROM. Performs calculation and processing, and functions as a main control unit.
When controlling the transfer unit, the main body control unit 50 ′ receives the state (resistance) of the transfer unit received as the primary transfer output feedback voltage from the high-voltage power supply unit 30 ′ in order to apply a predetermined transfer bias to the primary transfer unit. The target value (PWM signal) of the primary transfer current output corresponding to each transfer portion is output as a control set value by the method described below based on the detected value indicating ().
Here, the DUTY of the PWM signal instructing the primary transfer current output and the primary transfer output current value have the relationship shown in FIG. In FIG. 8, the vertical axis represents primary transfer output current (μA) and the horizontal axis represents PWM DUTY (%), and the relationship between the two is shown in a diagram. For example, when the PWM DUTY is P 1, P 2, P 3, P 4%, the corresponding primary transfer output current values are I 1, I 2, I 3, I 4 μA, and each point They are arranged on a straight line and have a linear relationship.
Further, the primary transfer output voltage and the primary transfer output feedback voltage have the relationship shown in FIG. In FIG. 9, the vertical axis represents the primary transfer output feedback voltage (V) and the horizontal axis represents the primary transfer output voltage (KV), and the relationship between the two is shown by a diagram. For example, when the primary transfer output voltages are KV 1, KV 2, KV 3, KV 4 KV, respectively, the corresponding primary transfer output feedback voltages are V 1, V 2, V 3, V 4 V, The points are arranged on a straight line and have a linear relationship.

The detection circuit 34 that detects the primary transfer output voltage detects the output voltage when the primary transfer output current is set to a predetermined value as a detection condition (for example, a PWM DUTY of a current of I 2 μA is set). The main body control unit 50 ′ receives a voltage corresponding to the primary transfer output voltage detected by the detection circuit 34 at this time as a primary transfer output feedback voltage. This feedback voltage depends on the resistance of the primary transfer portion at this time. That is, since the primary transfer output current at the time of detection by the detection circuit 34 is known (instructed I 2 μA), the control unit 50 ′ can determine the resistance of the primary transfer unit from the feedback voltage. Accordingly, the main body control unit 50 ′ obtains a target value of the primary transfer current output based on the primary transfer output feedback voltage (see the description of FIG. 11 below), and sends the corresponding setting PWM DUTY to the drive control unit 31 ′. Instructed as a control signal.
FIG. 10 is a control table showing the relationship between the primary transfer output feedback voltage (V) range and the PWM DUTY (%) and primary transfer output current value (μA) specified at each voltage range. Here, when the primary transfer output current such as I 2 μA is determined as a reference of the detection condition, the relationship with the primary transfer output feedback voltage (V) is shown, but naturally the primary transfer output feedback voltage (V ) May be used instead of the resistance value. In the control table illustrated in the figure, V 1 to V 4 of the primary transfer output feedback voltage V are divided into three areas,
When V 1 <V <V 2, PWM DUTY is P 3, primary transfer output current is I 3 μA,
When V 2 <V <V 3, PWM DUTY is P 2, primary transfer output current is I 2 μA,
When V 3 <V <V 4, PWM DUTY is P 1 and primary transfer output current is I 1 μA
Such a relationship is determined in advance.

FIG. 11 shows a target value determination process in this prior example in which the primary transfer current output target value is set by the resistance detection method.
As shown in FIG. 11, at the start of the image forming process (step S101), the target value is determined according to the flow shown in FIG. In this flow, first, the intermediate transfer belt is driven to be in an operating state (step S102). Here, the primary transfer output current target value is set as a reference value I 2 μA for resistance detection (step S103), the primary transfer output voltage is sampled at a predetermined sample period, and the average value of the detected primary transfer output voltages is determined. This is used as the primary transfer output feedback voltage value (step S104).
Next, from the relationship between the primary transfer output current and the output feedback voltage, the control table primary transfer resistance is calculated, and from the obtained resistance, the resistance: based on the control table of the primary transfer output current target value, The target value of the primary transfer output current until the next value is determined at a predetermined timing is determined (step S105). When the control table of FIG. 11 is used, it is determined to which setting range the primary transfer output feedback voltage value belongs, and the target value of the primary transfer output current is determined.
Thereafter, since this detection process is ended, the applied primary transfer output is stopped (step S106), the driving of the intermediate transfer belt is stopped (step S107), and this process is ended.

However, in the method of determining the primary transfer output current target value in the preceding example (FIGS. 7 to 11), it is necessary to provide a detection circuit 34 for detecting the resistance of the primary transfer portion on each of the four color components on the power supply board. This complicates the circuit configuration and increases the process control time for performing these detections during process control, impeding rapid processing. As a result, a process cartridge that requires a simple circuit configuration and low cost is unsuitable.
Therefore, in this embodiment, instead of the detection circuit 34 for detecting the resistance of the primary transfer portion, the resistance value of the primary transfer portion obtained in advance is used as the primary transfer rollers 16C and 16Y related thereto. , 16M, 16K and intermediate transfer belt 19 are held in each part as resistance values unique to the parts, and the resistance value is directly provided to the main body control unit from these parts constituting the mounted process cartridge during process control. As a method to obtain, the detection circuit 34 of the preceding example is unnecessary, and a simple circuit configuration and low cost are possible.
In the present embodiment, in order to maintain and manage resistance values unique to each component such as each primary transfer roller and intermediate transfer belt, IC tags are attached to these, and an IC tag reader / writer under the control of the main body control unit. Data manipulation such as reading / writing with respect to the IC tag is enabled by the device (the relationship with the main body control unit will be described in detail later).

FIG. 3 is a diagram showing an attached state of an IC tag (see FIG. 4 described later) including an IC chip and an antenna attached to the primary transfer rollers 16C, 16Y, 16M, and 16K and the intermediate transfer belt 19 of FIG. is there. As shown in FIG. 3, the IC tag 23 R is detachable from the primary transfer rollers 16 C, 16 Y, 16 M, and 16 K, and the IC tag 23 B is detachable from the intermediate transfer belt 19. As a detaching method, it is attached to each component with a double-sided adhesive tape provided on the mounting surface of the IC tag.
In the case of the primary transfer rollers 16C, 16Y, 16M, and 16K, the IC tags 23 R and 23 B are attached to the side portions of the roller ends as shown in FIG. Is the inner surface of the belt as shown in FIG. This mounting location is selected in consideration of preventing the transfer process from being affected even if the IC tags 23 R and 23 B are damaged by the operation of attaching and detaching them. That is, when the IC tag 23B is attached to the front side surface of the intermediate transfer belt 19, a toner image is formed on the front side surface. Therefore, if the IC tag 23B is damaged, streaks or the like occur in the formed image, which adversely affects image quality. Further, when the IC tag 23 R is attached to the surface portions of the primary transfer rollers 16C, 16Y, 16M, and 16K, a primary transfer bias is applied to the surface portion. It will have an adverse effect.
Further, the IC chips in the IC tags 23 R and 23 B have a built-in nonvolatile memory, and information on resistance values inherent to the primary transfer rollers 16C, 16Y, 16M, and 16K and the intermediate transfer belt 19 is stored in the nonvolatile memory. Pre-stored in memory. For the resistance value, it is possible to write the result measured at the part stage as an initial value and rewrite it to the correct value if a deviation is found from the stored resistance value at the subsequent maintenance stage. is there.

The main body control unit has an IC tag reader / writer device so that the IC tags 23 R and 23 B can access the nonvolatile memory built in the IC chip from the main body side. In the present embodiment, the primary transfer rollers 16C, 16Y, 16M, and 16K to which the IC tags 23 R and 23 B are respectively attached and the intermediate transfer belt 19 are movable members, and it is desirable to avoid mechanical contact. It is not appropriate to use a mechanical system for the interface with the IC tags 23 R and 23 B.
Therefore, an IC tag reader / writer device having a non-contact interface is adopted. FIG. 4 shows a schematic configuration of an IC tag and an IC tag reader / writer device attached to a process cartridge.
As shown in FIG. 4, the IC tags 23 R and 23 B attached to the primary transfer rollers 16C, 16Y, 16M, and 16K and the intermediate transfer belt 19, respectively, are composed of an IC chip 24 incorporating a nonvolatile memory and an antenna 25. The IC tag reader / writer device 26 includes an antenna 27, a reader / writer unit 28, and a control unit 29 including a CPU, RAM, ROM, and the like. The IC tag reader / writer device 26 includes an antenna 27 and an antenna 25 on the IC tags 23 R and 23 B side. It is arranged at an appropriate place in the apparatus main body within a range where radio waves can be transmitted and received between them.
Further, the control unit 29 of the IC tag reader / writer device 26 is connected to the primary transfer rollers 16C, 16Y, 16M, 16K and the intermediate transfer belt 19 by the reader / writer unit 28 via the antenna 27, respectively. 23, information of each resistance value received from B is sequentially stored, and based on the stored resistance value, a combined resistance value necessary for giving a predetermined transfer bias to the primary transfer portion for each color is obtained, Keep in memory. That is, a calculation is performed to synthesize the resistance of the primary transfer roller of each color and the resistance of the intermediate transfer belt. In the above processing, the CPU of the control unit 29 constituted by a CPU, a RAM, a ROM, etc. uses the RAM as a work area and performs an arithmetic function or the like according to a program or data necessary for this processing stored in the ROM. It can be realized by executing.

Next, the above-described IC tag method, that is, a method in which the resistance value of the primary transfer portion is given by the IC tag attached to the transfer component (primary transfer rollers 16C, 16Y, 16M, 16K and intermediate transfer belt 19) of the process cartridge. Thus, an embodiment for controlling the primary transfer bias will be described.
FIG. 5 shows a hardware configuration of a control system that applies a transfer bias of the primary transfer unit according to the IC tag method of the present embodiment.
The transfer bias control system shown in FIG. 5 is the above-described IC tag reader / writer connected to an IC tag attached to a transfer part (primary transfer rollers 16C, 16Y, 16M, 16K and intermediate transfer belt 19) of a process cartridge by a wireless interface. The high voltage power supply unit 30 is controlled by using the combined resistance value of the primary transfer unit obtained by the control unit 29 of the writer device (FIG. 4) in the main body control unit 50 of the device. By this control, a primary transfer output current that optimizes the primary transfer bias is output from the high-voltage power supply unit 30.
In order to perform this transfer bias control, the control unit 29 of the IC tag reader / writer device 26 and the main body control unit 50 are connected by a UART (Universal Asynchronous Receiver Transmitter).
The high-voltage power supply unit 30 controlled by the main body control unit 50 is provided with a booster circuit using a drive transformer 32 and a drive control unit 31 that drives this circuit in order to perform a high-voltage primary transfer output. The primary transfer output (output to the primary transfer roller) is a current-based constant current control method, and the primary transfer output current is detected by the detection circuit 33 in the high-voltage power supply unit and fed back to the drive control unit 31. . The drive control unit 31 receives the PWM signal from the main body control unit 50 as a control signal, and uses the received PWM signal as a primary transfer output target value to feed back the primary transfer output current detection value from the output side. And the output current control is performed. Although the primary transfer output current control is performed by the PWM signal instructed from the main body control unit 50, there is no difference from the preceding example (see FIG. 7), but in this embodiment, the primary transfer is performed by the IC tag method. Since the combined resistance value of the transfer portion is given, the primary transfer output voltage detection circuit required in the previous example is unnecessary.

The main body control unit 50 includes a CPU, a ROM that stores programs and data executed by the CPU, a RAM that the CPU uses as a work area, and the like, and performs operations according to various programs and data for controlling the entire apparatus stored in the ROM.・ Executes processing and other functions, and functions as a main control unit.
When controlling the transfer unit, the control unit 29 of the IC tag reader / writer device 26 obtains the resistance value acquired from the transfer part of the process cartridge by the IC tag method, and stores the latest primary transfer unit stored in the internal memory. The combined resistance value is transferred to the main body control unit 50 via the UART. The main body control unit 50 uses the following method to apply a predetermined transfer bias to the primary transfer unit based on the combined resistance value of the primary transfer unit received from the control unit 29 of the IC tag reader / writer device 26. Thus, the target value (PWM signal) of the primary transfer current output corresponding to the transfer unit of each color is output to the high voltage power supply unit 30 as a control set value.
That is, the control unit 50 obtains a target value of the primary transfer current output to be passed through the primary transfer unit in order to apply an appropriate transfer bias based on the combined resistance value of the primary transfer unit, and outputs the primary transfer current output. The setting PWM DUTY corresponding to the target value is instructed to the drive control unit 31 as a control signal. Note that the relationship between the DUTY of the PWM signal that instructs the primary transfer current output in the high-voltage power supply unit 30 and the primary transfer output current value is the same as the relationship shown in FIG.

FIG. 6 is a control table showing the relationship between the range of the primary transfer combined resistance value (MΩ) and the PWM DUTY (%) and the primary transfer output current value (μA) designated corresponding to each resistance value range. is there.
In the control table illustrated in FIG. 6, the range of the primary transfer combined resistance value (MΩ) is divided into four areas.
When R 1 <R <R 2, PWM DUTY is P 3, primary transfer output current is I 3 μA,
When R 2 <R <R 3, PWM DUTY is P 2, primary transfer output current is I 2 μA,
When R 3 <R <R 4, PWM DUTY is P 1, primary transfer output current is I 1 μA,
When R <R1, R> R4, PWM DUTY is fixed at 0% and the primary transfer output current is OFF.
Such a relationship is determined in advance.
The main body control unit 50 stores the control table as described above in a memory in advance, and acquires the combined resistance value of the primary transfer unit from the IC tag reader / writer device 26 to control the transfer bias applied to the primary transfer unit. At this time, by referring to the control table, a primary transfer output current target value corresponding to the combined resistance value of the primary transfer unit is obtained, and this target value (in this example, PWM DUTY) is used as a control signal as a high-voltage power supply. To the drive control unit 31 of the unit 30.
As described above, in the present embodiment, the primary transfer output voltage detection circuit required in the preceding example (see FIG. 7) is not required to obtain the primary transfer output current target value for each color. As described above, the circuit configuration of the high-voltage power supply unit 30 provided in the process cartridge can be simplified, and the suitability of the process cartridge requiring ease of maintenance and low cost can be improved. In addition, regarding the process control time, the primary transfer output voltage (transfer portion resistance) detection process of the target value determination process (see FIG. 11) performed by the resistance detection method of the previous example is unnecessary, and the four-color process is made unnecessary. Can be shortened by the amount of time.

In addition, an allowable range is provided for the combined resistance value of the primary transfer portion acquired from the IC tag reader / writer device 26, and a process in accordance with the abnormality is performed with a range that deviates from this range as an abnormal value. It is possible to prevent discharge and avoid deterioration in image quality.
The present embodiment will be described with reference to the example of the control table shown in FIG. 6. In this example, the range of the primary transfer combined resistance value (MΩ) satisfies the minimum allowable value R 1 divided into four areas. 6 and a range exceeding the maximum permissible value R 4, that is, in the range of R <R 1, R> R 4, it is determined as an abnormal value, and R 1 <R <R 4 (in the example of FIG. (Including three areas) is determined as a normal value.
Therefore, when it belongs to the range of R <R1, R> R4, the primary transfer output current is turned off as an error process, and an error is displayed on an operation unit (not shown) having a UI (User Interface) function. I do. In this case, in the example of the control table (FIG. 6) shown above, the PWM DUTY commanded as a control signal is fixed to 0% to turn off the primary transfer output current output and display an error display on the operation unit. Start the program to be executed.

1 is a diagram schematically showing the configuration of a color copying machine according to an embodiment of the present invention. 2 shows a main configuration of an image forming engine having a process cartridge in the color copying machine of FIG. FIG. 3 shows an attached state of IC tags attached to the four primary transfer rollers and the intermediate transfer belt of FIG. 2. A schematic configuration relating to an IC tag attached to a process cartridge and an IC tag reader / writer device installed in the main body is shown. 2 shows a hardware configuration of a control system for applying a transfer bias of a primary transfer portion by an IC tag method according to an embodiment of the present invention. 3 shows a control table showing the relationship between the range of primary transfer composite resistance value (MΩ) and PWM DUTY (%) and primary transfer output current value (μA) instructed correspondingly. 2 shows a hardware configuration of a control system of a previous example in which a transfer bias of a primary transfer unit is applied by a high voltage power supply unit using a resistance detection method. The relationship between the DUTY of the PWM signal which instruct | indicates the primary transfer current output in a high voltage power supply part, and a primary transfer output current value is shown. The relationship between the primary transfer output voltage and the primary transfer output feedback voltage in the preceding example (FIG. 7) is shown. 7 shows a control table of a prior example showing a relationship between a primary transfer output feedback voltage (V) range and PWM DUTY (%) and primary transfer output current value (μA) instructed correspondingly. The target value determination process in the prior example in which the primary transfer current output target value is set by the resistance detection method is shown.

Explanation of symbols

1: scanner unit 2: writing unit 3C: cyan photosensitive drum 3Y: yellow photosensitive drum 3M: magenta photosensitive drum 3K: black photosensitive drum 5C: cyan developing unit 5Y: yellow developing unit 5M: magenta developing unit 5K: black Development unit 6: Transfer unit 7: Paper feed tray (main unit)
11: Belt fixing unit 16C: Cyan transfer roller 16Y: Yellow transfer roller 16M: Magenta transfer roller 16K: Black transfer roller 17: Secondary transfer roller 18: Secondary transfer roller 19: Intermediate transfer belt 22: Process cartridge 23: IC Tag 24: IC chip 25: Antenna 26: IC tag reader / writer device 29: Control unit (built-in IC tag reader / writer device)
30: High voltage power supply unit 33: Primary transfer output current detection circuit 50: Main unit control unit

Claims (3)

In order to transfer the image carried on the first image carrier for each color to the second image carrier, the second image carrier via a transfer roller for each color provided corresponding to the first image carrier. secondary providing a primary transfer portion which gives a transfer bias, a charge of lifting image on the second image bearing member is transferred to the third image bearing member, a transfer bias to the second image carrier via the transcription roller A transfer unit, a high-voltage power supply unit that applies a transfer bias to the primary transfer unit and the secondary transfer unit, a transfer roller for each color of the primary transfer unit, and the second image carrier , A plurality of IC chips that read information on resistance values of the transfer rollers for each color of the next transfer unit and the second image carrier , and a plurality of non-contact communication means corresponding to each of the IC chips . an image forming apparatus using a process cartridge having IC tag, the There,
A tag reader / writer device for the plurality of IC tags;
The combined resistance of the primary transfer unit from the information of the resistance values of the transfer roller for each color of the primary transfer unit and the second image carrier acquired from the plurality of IC tags via the tag reader / writer device. When the calculated combined resistance value is out of a predetermined allowable range, the high-voltage power supply unit is not driven, a warning is displayed on the operation display unit of the image forming apparatus, and the calculated combined resistance is calculated. When the value falls within the allowable range, a control unit that drives the high-voltage power supply unit according to the value;
An image forming apparatus comprising: When the calculated combined resistance value falls within the allowable range, the control unit determines which of a plurality of predetermined ranges the combined resistance value is,
Outputting a PWM signal associated with the range including the combined resistance value to the high-voltage power supply unit;
The image forming apparatus according to claim 1. When the calculated combined resistance value is out of a predetermined allowable range, the control unit fixes and outputs a PWM signal output from the control unit to the high-voltage power supply unit at 0%,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus.

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