JP6805994B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus including a developing apparatus and a toner container.

The image forming apparatus includes a developing device that stores toner and supplies the toner to an image carrier such as a photoconductor drum, and a toner container that stores the toner to be supplied to the developing device. The toner container is replaceable with respect to the image forming apparatus, and the new toner container contains the maximum capacity of toner. The toner container is provided with an IC chip, and the IC chip stores information specific to the toner container in advance.

For example, in Patent Document 1, any of a photoconductor on which an electrostatic latent image is formed, a charging means for charging the photoconductor, and a developing means (developer) for developing an electrostatic latent image formed on the photoconductor. An image forming apparatus in which one or more of them are integrally unitized is disclosed. The image forming apparatus has a cartridge (toner container) having a storage medium capable of storing electronic information, which is detachably attached, and further includes an exposure means for exposing the photoconductor and a means for detecting the amount of the cartridge used. The storage medium stores threshold information for changing conditions and cartridge usage information unique to each cartridge. The image forming apparatus controls to change the exposure condition of the photoconductor based on the threshold value information and the usage amount information.

JP-A-2002-72573

In a developing device, even if new toner is replenished, old deteriorated toner may remain without being replaced. A mixed toner of new toner and deteriorated toner may deteriorate the developing performance of the developing apparatus. For example, when the positive electrode is charged with mixed toner for development, the toner charged on the negative electrode may be mixed due to the triboelectric charging between the new toner and the deteriorated toner. Therefore, the mixed toner causes image defects such as a decrease in image density and occurrence of fog. However, it is difficult to suppress image defects caused by mixed toner even if the exposure conditions are changed based on the amount of the toner container used as in the conventional image forming apparatus. Further, a configuration is conceivable in which the density of the image formed on the image carrier is measured and the printing processing conditions are corrected based on the measurement result, but such a configuration causes an increase in cost and arrangement space. become.

Further, even when printing with the same printing amount such as the number of dots and the printing rate, the amount of toner actually used may vary depending on the image forming apparatus. In other words, even if the amount of toner consumed for a predetermined printing amount is assumed in advance, the amount of toner actually used may differ. As a cause of the variation in the amount of toner actually used, it is considered that the accuracy of the image carrier, the developing device, the exposure device, the power supply device, and other parts provided in the image forming apparatus varies. For example, the distance between the photoconductor drum as the image carrier and the developing roller of the developing device (referred to as the distance between the drum sleeves or the developing gap) may vary. If this interval is widened, the developing electric field is weakened and the amount of development is reduced, which causes printing to be thinner than expected print quality. On the other hand, if this interval is narrowed, the developing electric field becomes stronger and the amount of development increases, which causes the printing to be darker than expected and the characters to be crushed. In addition, the surface potential and sensitivity of the photoconductor drum, the intensity of the laser beam of the exposure device, and the output value of the power supply device may also vary. Such variations in the accuracy of each component of the image forming apparatus may deteriorate the quality of the formed image.

Therefore, in consideration of the above circumstances, it is an object of the present invention to suppress image defects caused by old and new mixed toners while suppressing costs and arrangement space to realize desired print quality.

The image forming apparatus of the present invention includes a developing device that stores toner and supplies the toner to the image carrier, and a toner container that stores the toner that supplies the toner to the developing device, and is the maximum of the toner container. The printable amount preset in the toner container corresponding to the capacity is increased and corrected as the cumulative number of image-formed sheets increases, and the printable amount and the toner container are actually used. It is characterized in that the processing conditions for image formation are corrected so as to reduce the absolute value of the difference from the integrated print amount of the toner used.

The image forming apparatus may increase the printable amount and correct it as the ambient humidity of the developing apparatus increases.

When the toner container is replaced, the image forming apparatus uses the toner container after the replacement based on the difference between the printable amount and the integrated print amount of the toner container before the replacement. It is advisable to correct the above processing conditions.

The developing device includes a toner carrier that carries the toner and supplies the toner to the image carrier, and the image forming apparatus provides when the integrated print amount is larger than the printable amount. While the inter-peak voltage value of the development bias applied to the toner carrier is corrected to be high as the processing condition, when the integrated print amount is smaller than the printable amount, the inter-peak voltage value is used as the processing condition. It is good to correct it low.

According to the present invention, it is possible to achieve desired print quality by suppressing image defects caused by old and new mixed toner while suppressing costs and placement space.

It is sectional drawing which shows the printer which concerns on one Embodiment of this invention. It is sectional drawing which shows the toner container, the photoconductor drum and the developing apparatus of the printer which concerns on one Embodiment of this invention. It is a block diagram which shows the electrical structure of the printer which concerns on one Embodiment of this invention. It is a flowchart which shows the operation of the integrated print amount measurement and the print processing condition correction in the printer which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the cumulative number of sheets and the corrected integrated printing rate in the printer which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the cumulative number of sheets and the corrected integrated printing rate when the humidity change is taken into consideration in the printer which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the change amount of the voltage value between peaks of development bias, and the change ratio of the integrated print rate and the planned total amount of print rates in the printer which concerns on one Embodiment of this invention. It is a table which shows the relationship between the change amount of the voltage value between peaks of development bias, and the change rate of the integrated print rate and the planned total amount of print rates in the printer which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the required correction amount with respect to the expected total amount of print rate of the integrated print rate, and the correction amount of the voltage value between peaks of development bias in the printer which concerns on one Embodiment of this invention.

First, the overall configuration of the printer 1 (image forming apparatus) according to the embodiment of the present invention will be described with reference to FIG. Hereinafter, for convenience of explanation, the front side of the paper surface in FIG. 1 will be referred to as the front side of the printer 1. Arrows L, R, U, and Lo appropriately attached to each figure indicate the left side, right side, upper side, and lower side of the printer 1, respectively.

The printer 1 includes a substantially box-shaped printer main body 2, a paper feed cassette for storing paper is provided in the lower part of the printer main body 2, and a paper output tray is provided in the upper part of the printer main body 2.

An upper cover 3 is openably and closably attached to the upper surface of the printer main body 2 on the side of the output tray, and a toner container 4 is stored under the upper cover 3. By opening the upper cover 3, the storage space of the toner container 4 in the printer main body 2 is exposed, and the toner container 4 can be attached to and detached from the printer main body 2. The printer main body 2 includes a container detector 41 and a reader / writer unit 42 in the vicinity of the storage space of the toner container 4 (see FIG. 3). The container detector 41 detects the attachment / detachment of the toner container 4, that is, the replacement. The reader / writer unit 42 communicates with the IC chip 23 (see FIG. 3) of the mounted toner container 4 to read and write data.

An exposure device 5 composed of a laser scanning unit (LSU) is arranged below the output tray in the upper part of the printer main body 2, and an image forming unit 6 is provided below the exposure device 5. A photoconductor drum 7, which is an image carrier, is rotatably provided in the image forming unit 6, and a charger 8 and a developing device 9 connected to a toner container 4 are transferred around the photoconductor drum 7. The roller and the cleaning device are arranged along the rotation direction of the photoconductor drum 7. One end (for example, the rear end) of the rotation shaft of the photoconductor drum 7 is connected to a drum drive source 44 (see FIG. 3) such as a motor, and the photoconductor drum 7 is moved by the rotation drive force transmitted from the drum drive source 44. Rotate. The charging device 8 is connected to the charging bias applying unit 45, and charges the surface of the photoconductor drum 7 according to the charging bias applied from the charging bias applying unit 45.

A paper transport path 10 is provided inside the printer main body 2. A paper feed section is provided near the paper feed cassette at the upstream end of the transport path 10, and a transfer section composed of a photoconductor drum 7 and a transfer roller is provided at the middle stream portion of the transport path 10. A fixing device is provided in the downstream portion of the transport path 10, and a paper discharge section is provided in the vicinity of the paper output tray at the downstream end of the transport path 10.

Further, the printer main body 2 includes a control device 15 that controls each part of the printer 1 inside. Further, the printer main body 2 is provided with a display unit 17 on the upper surface or the side surface for displaying the state of the printer 1. The display unit 17 is composed of a touch panel, a display, or the like, and displays, for example, the remaining amount of toner in the toner container 4. The display unit 17 may be configured to include operation keys for operating the printer 1, such as a start key, a stop / clear key, and a numeric keypad.

Next, the image forming operation of the printer 1 having such a configuration will be described. When image data is input from an external computer or the like and an instruction to start printing is given, the printer 1 starts an image forming operation. In the image forming operation, first, the surface of the photoconductor drum 7 is charged by the charger 8 of the image forming unit 6, and then the exposure of the photoconductor drum 7 corresponding to the image data is performed by the laser beam from the exposure device 5. This is done to form an electrostatic latent image on the surface of the photoconductor drum 7. Next, the developing device 9 of the image forming unit 6 develops this electrostatic latent image into a toner image using toner.

On the other hand, the paper stored in the paper feed cassette is taken out by the paper feed unit and transported on the transport path 10. The paper on the transport path 10 is transported to the transfer unit at a predetermined timing, and the toner image on the photoconductor drum 7 is transferred to the paper by the transfer unit. The paper on which the toner image is transferred is conveyed to the fixing device, and the toner image is fixed on the paper by the fixing device. The paper on which the toner image is fixed is discharged from the paper ejection section to the output tray.

Next, the toner container 4 will be described. As shown in FIG. 2, the toner container 4 includes a container body 20 that houses toner inside. Inside the container body 20, a transport member 21 for supplying toner to the developing device 9 and a stirring member 22 for stirring the toner are provided. An IC chip 23 that stores container information regarding the toner container 4 is provided on the side surface of the container body 20.

The container body 20 is formed in a substantially box shape long in the front-rear direction, and has a supply port 20a opened on the lower surface. The supply port 20a communicates with the developing device 9 via the supply path 12.

The transport member 21 is rotatably attached to a position corresponding to the supply port 20a at the lower part of the container body 20. The transport member 21 is configured as, for example, a transport screw including a rotation shaft long in the front-rear direction and a spiral transport blade formed on the outer peripheral surface of the rotation shaft. One end (for example, the rear end) of the rotation shaft of the transport member 21 is connected to a container drive source 43 (see FIG. 3) such as a motor, and the transport member 21 is rotated by a rotational drive force transmitted from the container drive source 43. .. By rotating the transport member 21, the toner in the container body 20 is supplied to the developing device 9 via the supply port 20a and the supply path 12.

The stirring member 22 is rotatably attached in the container body 20 at substantially the center in the vertical direction. The stirring member 22 is composed of, for example, a rotating shaft long in the front-rear direction and stirring blades formed on the outer peripheral surface of the rotating shaft. The rotation of the stirring member 22 stirs the toner in the container body 20.

The IC chip 23 can communicate with the reader / writer unit 42 connected to the control device 15 with the toner container 4 mounted on the printer main body 2, and even if the IC chip 23 communicates via an antenna (not shown). Good. The IC chip 23 includes a storage medium (not shown) such as a non-volatile memory, and stores container information of the toner container 4.

The IC chip 23 stores, for example, the maximum amount of toner stored in the container body 20 of a new toner container 4 as container information of the toner container 4. Further, the IC chip 23 is a dot that can be printed before the maximum capacity of toner is used up on the premise that the printer 1 prints (image formation) with a predetermined print quality (for example, density) as container information. Stores the planned total amount (printable amount) such as the number and print rate. For example, printing that fills the entire surface of A4 size paper with toner is indicated by a printing rate of 100%, and in this case, printing that fills the entire surface of A3 size paper with toner is indicated by a printing rate of 200%. Printing rate as the printable amount of the toner container 4 When the planned total amount is 25,000%, when the maximum capacity of the toner in the toner container 4 is used up by repeating printing on A4 size paper at a printing rate of 5%, 5000 pages Can print paper. Further, the IC chip 23 stores as container information the integrated value (integrated printing amount) of the printing amount such as the printing rate and the number of dots when printing is performed by the printer 1 actually using the toner in the toner container 4. To do. For example, the IC chip 23 of the new toner container 4 stores a cumulative printing rate of 0%.

Next, the developing apparatus 9 will be described. As shown in FIG. 2, the developing apparatus 9 includes a housing 30 for accommodating toner, and inside the housing 30, a developing roller 31 (toner carrier) for supplying toner to the photoconductor drum 7 and toner are placed. A stirring member 32 and a transport member 33 for stirring and transporting are provided. Further, the developing device 9 includes a toner amount sensor 34 that detects the amount of toner in the housing 30, and a humidity sensor 35 that detects the humidity around the developing device 9.

The housing 30 is formed in a substantially box shape long in the front-rear direction, and has an opening opened on the left side so as to face the photoconductor drum 7 and a supply port 31a opened on the upper surface. The supply port 31a communicates with the toner container 4 via the supply path 12.

The developing roller 31 is arranged so as to face and contact the photoconductor drum 7 through the opening, has a long rotation axis in the front-rear direction, and is rotatably attached to the housing 30. One end (for example, the rear end) of the rotating shaft of the developing roller 31 is connected to a developing driving source 46 (see FIG. 3) such as a motor, and the developing roller 31 is rotated by a rotational driving force transmitted from the developing driving source 46. .. By rotating the developing roller 31, the toner in the housing 30 is supplied to the photoconductor drum 7. Further, the developing roller 31 is connected to the developing bias applying unit 47 (see FIG. 3), and is charged according to the developing bias applied from the developing bias applying unit 47 to support the toner on the surface.

The stirring member 32 and the transport member 33 are arranged side by side in the lower part of the housing 30, and in particular, the transport member 33 is arranged below the supply port 30a. The stirring member 32 and the conveying member 33 have a long rotation axis in the front-rear direction and are rotatably attached to the housing 30. By rotating the stirring member 32 and the conveying member 33, the toner in the housing 30 is conveyed to the developing roller 31 while being agitated.

The toner amount sensor 34 detects whether or not the amount of toner in the housing 30 is less than a predetermined first threshold value. When the amount of toner in the housing 30 is less than the first threshold value, it is determined that the developing apparatus 9 is in a toner low state in which the developing device 9 does not contain a sufficient amount of toner for development (needs to supply toner from the toner container 4). Toner. Further, the toner amount sensor 34 detects whether or not the amount of toner in the housing 30 is less than a predetermined second threshold value, which is smaller than the first threshold value. When the amount of toner in the housing 30 is less than the second threshold value, it is determined that the amount of toner in the developing device 9 is empty (requires replacement of the toner container 4) and is in a toner empty state.

Next, the electrical configuration of the control device 15 will be described with reference to FIG. The control device 15 is composed of a CPU or the like, and is connected to a storage device 16 such as a ROM or RAM. Further, the control device 15 includes a container detector 41, a reader / writer unit 42, a container drive source 43, a drum drive source 44, a charge bias application unit 45, a development drive source 46, a development bias application unit 47, and a toner amount sensor 34. It is connected to each part of the printer 1 such as the humidity sensor 35 and the display part 17.

The control device 15 controls each unit connected to the control device 15 based on the control program and control data stored in the storage device 16. The control device 15 measures, for example, the cumulative number of prints (image formation) by the printer 1 since the start of use of the new printer 1 or the new developing device 9, that is, the cumulative number of printed sheets. Measure the number of sheets. Further, the control device 15 determines the printing rate when printing is actually performed using the toner in the toner container 4 between the time when the new toner container 4 is installed and the time when the toner container 4 is used and replaced. The integrated print amount measurement is performed to measure the integrated value (integrated print amount) of the print amount such as the number of dots. Further, the control device 15 corrects the processing conditions for correcting the printing processing conditions based on the measured integrated print amount. The printing processing conditions are setting conditions for each part in which the toner density, usage amount, and printing rate can be changed.

The printing processing conditions include, for example, the peak voltage value Vpp of the AC square wave of the development bias applied to the development roller 31 by the development bias application unit 47, the center voltage value Vdc (DC component) of the area average, the frequency Vf, and the frequency Vf. There is a duty ratio Vduty. Further, the processing conditions include a linear speed ratio S / D of the developing roller 31 driven by the developing driving source 46 with respect to the photoconductor drum 7 driven by the drum driving source 44. Further, the processing conditions include the surface potential of the photoconductor drum 7 to which the charging bias is applied by the charging bias applying unit 45 and the charging device 8. Further, the processing conditions include the intensity of the laser light from the exposure device 5, the number of dots (resolution) of the image data, and the like.

The above-mentioned operations of cumulative paper number measurement, integrated print amount measurement, and processing condition correction will be described with reference to the flowchart of FIG. When a new toner container 4 is attached to the printer main body 2, the control device 15 detects the attachment of the toner container 4 by the container detector 41 and controls the container drive source 43 to rotate the transport member 21 of the toner container 4. As a result, toner is replenished from the toner container 4 to the developing device 9 (step S1). Toner replenishment is performed until the amount of toner in the housing 30 of the developing device 9 becomes equal to or higher than the first threshold value based on the detection result of the toner amount sensor 34.

Further, when the toner container 4 is attached, the control device 15 reads the container information from the IC chip 23 of the toner container 4 by the reader / writer unit 42 (step S2). As a result, the control device 15 grasps the printable amount which is the container information of the toner container 4, and for example, grasps the total print rate planned amount as the printable amount. For example, in the case of a regular replacement toner container 4, the total planned print rate is set to 50,000%, and in the case of the trial toner container 4 bundled with the new printer 1, the total planned print rate is the regular toner container. It is set to 25000%, which is less than 4. Whether the toner container 4 is trial or regular may be determined based on the planned total print rate of the container information, or may be determined based on the trial or regular information included in the container information.

When the toner supply is completed, the printer 1 is ready for printing, and the control device 15 controls each part to print each time the image data and the printing start instruction are input (step S3). The control device 15 grasps the print rate as the print amount per sheet of paper based on the image data and the contents of the print start instruction. The control device 15 integrates the print rate each time printing is performed and stores the integrated print rate (integrated print amount) in the storage device 16, and the reader / writer unit 42 stores the integrated print rate in the IC chip 23 of the toner container 4. (Step S4). Further, each time the control device 15 prints, the cumulative number of prints, that is, the cumulative number of sheets of paper is measured and stored in the storage device 16 (step S5). In the case of single-sided printing on one sheet of paper, one sheet is accumulated in the cumulative number of sheets, and in the case of double-sided printing on one sheet of paper, two sheets are accumulated in the cumulative number of sheets.

The control device 15 calculates the remaining amount of toner in the toner container 4 based on the integrated printing rate of the toner container 4 and the planned total amount of the printing rate, and displays it on the display unit 17. For example, when the total planned printing rate is 25,000% and the integrated printing rate is 5000%, the remaining amount of toner is calculated to be 80% by subtracting the ratio between the total planned printing rate and the integrated printing rate from 100%. Toner. The control device 15 reduces the remaining amount of toner in the toner container 4 in 1% increments as the integrated printing rate of the toner container 4 increases, and displays the toner on the display unit 17. The remaining amount of toner in the toner container 4 is 100% immediately after replacement with a new toner container 4 (initial state) and 0% in the toner empty state of the developing device 9, and the remaining amount of toner is changed according to the change in the integrated printing rate. May be displayed so as to change linearly, but may be displayed slightly less than the actually calculated remaining amount of toner.

Further, the control device 15 monitors the amount of toner in the housing 30 of the developing device 9 by the toner amount sensor 34. When the amount of toner in the housing 30 becomes less than the first threshold value while printing is continued (step S6: YES), the control device 15 controls the container drive source 43 to transfer the toner container 4 to the developing device 9. Toner replenishment is performed (step S7).

If the amount of toner in the container body 20 of the toner container 4 decreases while the toner replenishment is continued, a sufficient amount of toner cannot be replenished to the developing device 9. Then, when the toner in the container body 20 becomes empty, the toner is not replenished, so that the amount of toner in the housing 30 becomes less than the first threshold value (step S8: YES), and in the control device 15, the developing device 9 is a toner low. It is determined that the state is in the state (step S9), and the toner low state is notified to the user by the speaker (not shown) or the display unit 17.

The planned total amount of the print rate corresponding to the toner corresponding to the first threshold value of the developing device 9 is set to a predetermined secured amount, for example, 2500%, regardless of the set processing conditions (print quality). Has been done. When the toner in the housing 30 becomes less than the first threshold value, that is, when the developing device 9 is in the toner low state, the control device 15 sets the remaining amount of toner in the toner container 4 to the first, regardless of the integrated printing rate. It is displayed on the display unit 17 as 5% according to the planned total amount of the print rate corresponding to the threshold value. For example, when the trial toner container 4 is installed, when the integrated printing rate reaches 22500%, the remaining amount of toner is calculated to be 10% with respect to the planned total printing rate of 25000% of the toner container 4, but it is controlled. The device 15 displays 10% of the remaining amount of toner in the toner container 4 and immediately displays 5% on the display unit 17.

By the way, the control device 15 does not display 5% or less of the remaining amount of toner in the toner container 4 on the display unit 17 regardless of the integrated printing rate until the developing device 9 is in the toner low state. For example, when the trial toner container 4 is installed, when the integrated printing rate reaches 23750%, the remaining amount of toner is calculated to be 5% with respect to the planned total printing rate of 25,000% of the toner container 4, but development is performed. When the toner of the first threshold value or more is contained in the housing 30 of the device 9 and the toner low state is not determined, the control device 15 displays 6% as the remaining amount of toner in the toner container 4 on the display unit 17. Continue to do.

Then, when the developing apparatus 9 is in the toner low state, it is possible to print a predetermined secured amount (2500%) with the toner in the developing apparatus 9. For example, when a regular toner container 4 is installed, if the integrated printing rate when the developing device 9 is in the toner low state is 52635%, further 2500% printing is possible, so that toner container 4 The integrated printing rate that can be achieved by using all the toners in the above is 54856%. After the toner low state, the control device 15 reduces the remaining amount of toner in the toner container 4 by 1% every time the printing rate is accumulated by 500%, regardless of the maximum capacity of the mounted toner container 4. Display on 17.

If the amount of toner in the housing 30 becomes less than the second threshold value (step S10: YES) while printing is continued from the toner low state, the control device 15 determines that the developing device 9 is in the toner empty state (step S10: YES). Step S11), the speaker (not shown) and the display unit 17 notify the user of the toner empty state, and prompt the user to replace the toner container 4. At this time, the control device 15 displays 0% as the remaining amount of toner in the toner container 4 on the display unit 17. If the integrated print rate written on the IC chip 23 of the toner container 4 reaches the planned total print rate, the control device 15 can determine that the toner container 4 cannot be used.

When replacing the toner container 4 (step S12), if the toner container 4 before replacement is a regular one (step S13: YES), the control device 15 reads from the IC chip 23 of the toner container 4 before replacement. The total planned printing rate is corrected based on the cumulative number of sheets up to that point (step S14). For example, the control device 15 increases and corrects the planned total print rate as the cumulative number of sheets of paper increases. Specifically, as shown in FIG. 5, when the cumulative number of sheets exceeds a predetermined number threshold value (for example, 100,000 sheets), the larger the cumulative number of sheets, the more the planned total print rate is corrected. If the cumulative number of sheets is less than or equal to the number threshold value, the total planned print rate is not corrected. Further, as the upper limit of the correction, a predetermined upper limit value of the cumulative number of sheets (for example, 300,000 sheets) or a predetermined upper limit value of the planned total print rate (for example, 53000%) is set. As the cumulative number of sheets of paper increases, the slope of the increase in the planned total print rate may be moderated.

Further, the control device 15 monitors the humidity around the developing device 9 by the humidity sensor 35, and may correct the total planned printing rate based on the surrounding humidity. For example, the control device 15 increases and corrects the planned total print rate as the ambient humidity of the developing device 9 increases. Specifically, while the toner container 4 before replacement is being used, the control device 15 detects the ambient humidity of the developing device 9 at the time of printing by the humidity sensor 35 and stores it in the storage device 16. Then, when the toner container 4 is replaced, the control device 15 averages the ambient humidity of the developing device 9 stored in the toner container 4 before replacement, and the average ambient humidity is a predetermined humidity threshold value (for example, 20 g / m ^3). ) Or more, as shown in FIG. 6, a predetermined addition amount (for example, 20000%) is added to the planned total print rate amount for correction (see the two-dot chain line).

Then, the control device 15 corrects the printing processing conditions for printing using the toner container 4 after the replacement, based on the integrated printing rate of the toner container 4 before the replacement and the planned total amount of the printing rate after the correction. The processing condition is corrected (step S15). The printing processing conditions are, for example, in the initial state before the replacement of the toner container 4, the peak voltage value Vpp is set to 1325V, the center voltage value Vdc is set to 135V, and the frequency Vf is set for the development bias of the developing roller 31. 3.1 kV is set to, and 64% is set to the duty ratio Vduty. Further, the linear velocity ratio S / D of the developing roller 31 with respect to the photoconductor drum 7 is set to 1.4 to 1.5 times, and the surface potential of the photoconductor drum 7 is set to 220 V.

On the other hand, in the correction of the processing conditions, the processing conditions are adjusted so that the absolute value of the difference between the integrated print rate and the planned total print rate is reduced and disappears, that is, the integrated print rate approaches the total planned print rate. Correct each value. As the actual integrated printing rate of the toner container 4 before replacement becomes larger than the planned total printing rate, it can be assumed that the actual printing is lighter. Therefore, the processing conditions are corrected so as to increase the toner usage amount and the density. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, it can be assumed that the actual printing is darker. Therefore, the processing conditions are corrected so as to reduce the amount of toner used and the density. For example, when the inter-peak voltage value Vpp of the development bias by the development bias application unit 47 is corrected, the inter-peak voltage value Vpp is corrected higher as the integrated print rate becomes larger than the planned total print rate. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, the peak voltage value Vpp is corrected to be lower. The inter-peak voltage value Vpp is corrected within a range of a predetermined lower limit value (for example, 1025V) or more and a predetermined upper limit value (for example, 1625V) or less.

As a result of conducting an experiment by changing the peak voltage value Vpp, as shown in FIGS. 7 and 8, as the change amount (Vpp change amount) of the peak voltage value Vpp increases, the integrated print rate and the print rate are planned. The ratio of the difference from the total amount to the planned total amount of printing rate (toner consumption change ratio) changes so as to increase. In other words, the toner consumption change ratio is the correction amount (toner consumption required correction amount) required to match the integrated printing rate with the planned total printing rate, and as shown in FIG. 9, the toner consumption required. As the amount of correction increases, the amount of correction (Vpp correction amount) that increases the inter-peak voltage value Vpp increases. Therefore, the Vpp correction amount can be calculated based on the integrated print rate of the toner container 4 before replacement and the planned total amount of print rate after correction.

For example, when the planned total printing rate is 50,000% and the integrated printing rate is 54865%, the actual printing rate is about 9.73% more, that is, the required correction amount for toner consumption is about 9.73. %. In order to correct the required correction amount of toner consumption of about 9.73%, as shown in FIG. 9, a Vpp correction amount of about 84V is required. If the peak voltage value Vpp before correction is 1325V, the peak voltage value Vpp of the development bias of the developing roller 31 is corrected to 1409V for printing (image formation) using the toner container 4 after replacement. ..

When the center voltage value Vdc of the development bias by the development bias application unit 47 is corrected, the center voltage value Vdc is corrected higher as the integrated print rate of the toner container 4 before replacement becomes larger than the planned total print rate. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, the center voltage value Vdc is corrected lower. When the frequency Vf or duty ratio Vduty of the development bias by the development bias application unit 47 is corrected, the frequency Vf or duty ratio Vduty is corrected smaller as the integrated print rate of the toner container 4 before replacement becomes larger than the planned total print rate. To do. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, the frequency Vf or the duty ratio Vduty is corrected more greatly.

Further, when the linear speed ratio S / D between the developing roller 31 and the photoconductor drum 7 by the developing drive source 46 and the drum driving source 44 is corrected, the integrated printing rate of the toner container 4 before replacement is larger than the planned total printing rate. Indeed, the linear speed ratio S / D is corrected more greatly. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, the linear speed ratio S / D is corrected to be smaller. When correcting the surface potential of the photoconductor drum 7 by the charging bias applying unit 45 and the charging device 8, the surface potential is corrected lower as the integrated printing rate of the toner container 4 before replacement becomes larger than the planned total printing rate. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, the surface potential is corrected higher.

Further, when correcting the intensity of the laser beam by the exposure device 5, the intensity is corrected more strongly as the integrated printing rate of the toner container 4 before replacement becomes larger than the planned total printing rate. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, the strength is corrected weaker. When correcting the number of dots (resolution) of image data, the more the integrated print rate of the toner container 4 before replacement becomes larger than the planned total print rate, the more the number of dots is corrected. On the other hand, as the integrated printing rate becomes smaller than the planned total printing rate, the number of dots is corrected to be smaller. The number of dots in the image data may be corrected so as to change the resolution of the image data by image processing.

By the way, after the developing device 9 is in the toner low state and before the toner empty state is reached, the toner container 4 may be replaced even though the toner remains in the developing device 9. That is, the developing apparatus 9 contains the remaining amount of toner before replacement supplied from the toner container 4 before replacement. Therefore, the control device 15 calculates the print rate of the toner container 4 after replacement by adding the remaining amount before replacement to the total planned print rate (printable amount) read from the IC chip 23 of the toner container 4 after replacement. Assume total amount.

For example, if the toner container 4 is replaced when the printing rate is integrated up to 700% from the toner low state, the developing device 9 contains the remaining amount of toner before replacement corresponding to the printing rate of 1800%. In this case, if the IC chip 23 of the toner container 4 after replacement stores a total planned printing rate of 50,000%, the total planned printing rate of the toner container 4 after replacement is assumed to be 51800%. Then, the control device 15 calculates the remaining amount of toner in the toner container 4 based on the assumed total planned printing rate and the integrated printing rate (integrated printing amount).

According to the present embodiment, as described above, the printer 1 (image forming apparatus) includes the toner and supplies the toner to the photoconductor drum 7 (image carrier), and the developing apparatus 9 and the developing apparatus 9. It includes a toner container 4 for accommodating toner to be replenished. Then, the control device 15 of the printer 1 increases the printable amount preset in the toner container 4 corresponding to the maximum capacity of the toner container 4 as the cumulative number of image-formed papers increases. The printing (image formation) processing conditions are set so as to correct and reduce the absolute value of the difference between the printable amount and the integrated print amount of the toner actually used from the toner container 4 based on the printable amount. to correct.

As a result, even if the print quality differs from what was previously assumed due to the variation in the accuracy of each component of the printer 1, and the amount of toner used for printing varies, the actual integrated print amount is assumed. It is possible to obtain the printing processing conditions so as to match the printable amount. Further, even when new toner and old deteriorated toner are mixed in the developing apparatus 9, the printable amount is obtained in consideration of the degree of mixing of the deteriorated toner, so that more preferable printing processing conditions can be obtained. Therefore, image defects caused by the old and new mixed toner can be suppressed. Therefore, regardless of the variation in the accuracy of each component, it is possible to exhibit the expected desired print quality and suppress the variation in the amount of toner used for printing. According to the present embodiment, it is not necessary to provide a dedicated component for detecting deteriorated toner and measuring the density of the image, so that the cost and the arrangement space can be suppressed.

Further, the control device 15 of the printer 1 increases the printable amount and corrects it as the ambient humidity of the developing device 9 increases. For example, due to an increase in the ambient humidity of the developing apparatus 9, the developability may decrease, the toner consumption may decrease, and the actual integrated printing amount may increase. Even in such a case, since the printable amount is corrected according to the ambient humidity, the difference between the integrated print amount and the printable amount can be calculated correctly regardless of the ambient humidity, and the print processing conditions can be obtained correctly. be able to. Therefore, it is possible to suppress image defects caused by the ambient humidity of the developing device 9.

Further, when the toner container 4 is replaced, the control device 15 of the printer 1 uses the toner container 4 after the replacement based on the difference between the printable amount and the integrated print amount of the toner container 4 before the replacement. Correct the processing conditions. As a result, when the toner container 4 is replaced, the difference between the expected print quality and the actual print quality can be correctly grasped, and the print processing conditions can be corrected more correctly.

Further, in the printer 1, the developing device 9 includes a developing roller 31 (toner carrier) that carries toner and supplies toner to the photoconductor drum 7, and the control device 15 has a cumulative print amount larger than the printable amount. When the amount is large, the inter-peak voltage value Vpp of the development bias applied to the developing roller 31 is corrected to be high as a processing condition, while when the integrated print amount is smaller than the printable amount, the inter-peak voltage value Vpp is applied as a processing condition. Is corrected low. As a result, by correcting the peak-to-peak voltage value Vpp of the development bias of the developing roller 31, the responsiveness of the correction of the print quality can be improved and the influence on other members can be suppressed.

In the present embodiment, the case where the configuration of the present invention is applied to the monochrome printer 1 has been described, but in other different embodiments, the present invention is applied to other image forming apparatus such as a color printer, a copying machine, a facsimile, and a multifunction device. It is also possible to apply the configuration of.

1 Printer (image forming device)
4 Toner container 5 Exposed device 6 Image forming part 7 Photoreceptor drum (image carrier)
8 Charger 9 Developing device 15 Control device 17 Display unit 20 Container body 21 Conveying member 23 IC chip 30 Housing 31 Developing roller (toner carrier)
34 Toner amount sensor 35 Humidity sensor 41 Container detector 42 Reader / writer unit 43 Container drive source 44 Drum drive source 45 Charge bias application unit 46 Development drive source 47 Development bias application unit

Claims (3)

A developing device that contains toner and supplies the toner to the image carrier,
A toner container for accommodating the toner to be supplied to the developing apparatus is provided.
The printable amount preset in the toner container corresponding to the maximum capacity of the toner container is increased and corrected as the cumulative number of image-formed papers increases, and the toner container is replaced. At that time, the printable amount and the integrated print amount of the toner container before replacement are reduced so as to reduce the absolute value of the difference between the printable amount and the integrated print amount of the toner actually used from the toner container. An image forming apparatus, which corrects the processing conditions for image forming using the toner container after replacement based on the difference between the two. The image forming apparatus according to claim 1, wherein the printable amount is increased and corrected as the ambient humidity of the developing apparatus increases. The developing apparatus includes a toner carrier that supports the toner and supplies the toner to the image carrier.
When the integrated print amount is larger than the printable amount, the inter-peak voltage value of the development bias applied to the toner carrier as the processing condition is corrected to be high, while the inter-peak voltage value is corrected to be high.
The image forming apparatus according to claim 1 or 2 , wherein when the integrated print amount is smaller than the printable amount, the inter-peak voltage value is corrected to be low as the processing condition.

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