Image forming device

Abstract

To provide a configuration that can make adjustment of a transfer voltage efficient.SOLUTION: In a secondary transfer voltage adjustment mode, a semiautomatic adjustment mode including a test chart output mode can be executed. In the test chart output mode, an image chart for adjustment is output while the secondary transfer voltage is switched for every pattern image. In the semiautomatic adjustment mode, the image chart for adjustment is read by an image reading unit to acquire density data of the pattern image, and the optimal numeric value and adjustment value of the pattern image are determined based on the acquired density data. That is, the adjustment value for a transfer voltage is automatically selected. When an automatically selected adjustment value (automatic selection value) is not OK, a user inputs an offset value to the automatic selection value. Subsequently, in the semiautomatic adjustment mode, when the image chart for adjustment is read by the image reading unit, an adjustment value on which the offset value is reflected is selected.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus such as a copier, a printer, a facsimile, or a multifunction machine having a plurality of these functions. [Background technology]

[0002] In an image forming apparatus, a toner image is transferred from a photosensitive drum directly or via an intermediate transfer belt to a recording material. For this reason, a transfer member is provided between the photosensitive drum or the intermediate transfer belt to form a transfer section for transferring the toner image. In addition, a method for appropriately setting a transfer voltage to be applied to the transfer section during image formation has been conventionally known.

[0003] For example, Patent Document 1 describes a method (secondary transfer voltage adjustment mode) in which multiple pattern images transferred with different transfer voltages are output, an optimal transfer voltage is selected based on the pattern images, and the optimal transfer voltage is reflected in the transfer voltage during image formation. Patent Document 1 also describes a mode in which the optimal secondary transfer voltage is automatically selected based on density data acquired by reading the multiple output pattern images with a reading device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-37185 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of the mode in which the optimal secondary transfer voltage described in Patent Document 1 is automatically selected, the automatically selected secondary transfer voltage is selected based on a selection criterion that is preset in the device. Therefore, depending on the user's preference for transfer image quality, there may be cases where the user wants to set a stronger or weaker value than the automatically selected value. In such cases, it is considered that the automatically selected value must be manually re-input each time. However, if the user manually re-selects the desired value each time the above-mentioned mode is implemented, the time required for adjusting the secondary transfer voltage will increase, reducing work efficiency.

[0006] An object of the present invention is to provide a configuration that can improve the efficiency of adjustment of the transfer voltage. [Means for solving the problem]

[0007] One aspect of the present invention is ,toa control unit that executes an adjustment mode for outputting a test chart for adjusting the transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to the recording material while applying a plurality of different test voltages to the transfer member, the test chart being formed by adjusting the transfer voltage, and an operation unit that allows manual input of information, and the control unit controls the display unit to display setting information of the transfer voltage to be set during a transfer period based on a detection result of the test chart detected by the concentration detection unit in the adjustment mode. and capable of receiving correction information from the operation unit for correcting the setting information displayed on the display unit, and determining a transfer voltage to be set during the transfer period based on the correction information input from the operation unit, the image forming device being configured to be able to log in for each user, and the control unit, during the current adjustment mode, based on the detection result of the test chart output during the current adjustment mode detected by the density detection unit and the correction information input from the operation unit during the previous adjustment mode, determines whether or not to display based on the correction information input in the adjustment mode previously executed, depending on the user logged in to the image forming device. According to one aspect of the present invention, there is provided a recording medium comprising: an image forming unit which forms a toner image; an image carrier which carries the toner image formed by the image forming unit; a transfer member which transfers the toner image from the image carrier to a recording material; a power source which applies a transfer voltage to the transfer member; a density detection unit which is capable of detecting density information of an image formed on the recording material; a display unit which is capable of displaying the information; a control unit which is capable of executing an adjustment mode which outputs a test chart for adjusting the transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to the recording material while applying a plurality of different test voltages to the transfer member; and an operation unit which is capable of manually inputting information, wherein in the adjustment mode, the control unit is configured to determine a value of the transfer voltage to be set during a transfer period based on a detection result of the test chart detected by the density detection unit. This image forming apparatus is characterized in that it displays setting information on the display unit, is capable of receiving correction information from the operation unit for correcting the setting information displayed on the display unit, and determines a transfer voltage to be set during the transfer period based on the correction information input from the operation unit, and when displaying on the display unit, during the current adjustment mode, the control unit determines whether or not to display based on the correction information input in the previous adjustment mode, depending on the type of recording material on which the test chart output in the current adjustment mode is formed, based on the detection result of the test chart output during the current adjustment mode detected by the density detection unit and the correction information input from the operation unit during the previous adjustment mode. According to one aspect of the present invention, there is provided a recording medium comprising: an image forming unit that forms a toner image; an image carrier that carries the toner image formed by the image forming unit; a transfer member that transfers the toner image from the image carrier to a recording material; a power source that applies a transfer voltage to the transfer member; a density detection unit that is capable of detecting density information of an image formed on the recording material; a display unit that is capable of displaying information; a control unit that is capable of executing an adjustment mode that outputs a test chart for adjusting the transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to the recording material while applying a plurality of different test voltages to the transfer member; and an operation unit that allows information to be manually inputted, wherein in the adjustment mode, the control unit causes the display unit to display setting information of a transfer voltage to be set during a transfer period based on a detection result of the test chart detected by the density detection unit, and outputs correction information for correcting the setting information displayed on the display unit. and determining a transfer voltage to be set during the transfer period based on the correction information input from the operation unit, and the control unit, during the current adjustment mode, causes the display unit to display setting information for the transfer voltage to be set during the transfer period based on a detection result obtained by detecting the density of the test chart output during the current adjustment mode by the density detection unit and the correction information input from the operation unit during the previous adjustment mode, and when a type of the recording material on which the test chart output in the previous adjustment mode is formed is a first type and a type of the recording material on which the test chart output in the current adjustment mode is formed is a second type different from the first type, the control unit displays the transfer voltage to be displayed in the current adjustment mode based on the correction information input in the previous adjustment mode. According to one aspect of the present invention, there is provided a recording medium for recording an image on a recording medium, the recording medium comprising: an image forming unit which forms a toner image; an image carrier which carries the toner image formed by the image forming unit; a transfer member which transfers the toner image from the image carrier to a recording material; a power source which applies a transfer voltage to the transfer member; a density detection unit which is capable of detecting density information of an image formed on the recording material; a display unit which is capable of displaying the information; a control unit which is capable of executing an adjustment mode which outputs a test chart for adjusting the transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to the recording material while applying a plurality of different test voltages to the transfer member; and an operation unit which is capable of manually inputting information. an image forming apparatus that displays setting information for a transfer voltage to be set during a transfer period on the display unit, is capable of receiving correction information from the operation unit for correcting the setting information displayed on the display unit, and determines a transfer voltage to be set during the transfer period based on the correction information input from the operation unit, and the control unit, during the current adjustment mode, is capable of selectively determining whether to display the transfer voltage based on the correction information input in the previous adjustment mode when displaying setting information for the transfer voltage to be set during the transfer period on the display unit based on the detection result obtained by the density detection unit detecting the test chart output during the current adjustment mode and the correction information input from the operation unit during the previous adjustment mode. Effect of the Invention

[0008] According to the present invention, the transfer voltage can be adjusted more efficiently. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment. [Diagram 2] FIG. 2 is a control block diagram of the image forming apparatus according to the embodiment. [Diagram 3] 4 is a flowchart of ATVC control according to the embodiment. [Figure 4] 6 is a diagram showing an example of an adjustment image chart in a secondary transfer voltage adjustment mode according to the embodiment. FIG. [Diagram 5] FIG. 13 is a diagram showing another example of the adjustment image chart in the secondary transfer voltage adjustment mode according to the embodiment. [Figure 6] 11 is a flowchart of a secondary transfer voltage adjustment mode according to a comparative example. [Figure 7] FIG. 6 is a diagram showing an example of a setting screen for a secondary transfer voltage adjustment mode. [Figure 8] 6 is a graph for explaining a transfer voltage setting in a secondary transfer voltage adjustment mode according to an embodiment. [Figure 9] 13A is a flowchart of a secondary transfer voltage adjustment mode according to an embodiment, and FIG. 13B is a flowchart of a secondary transfer voltage adjustment mode after an initial adjustment. [Figure 10] FIG. 6 is a view showing an example of a setting screen for an offset value in a secondary transfer voltage adjustment mode according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiment will be described with reference to Figures 1 to 10. First, the image forming apparatus of the present embodiment will be described with reference to Figures 1 and 2.

[0011] [Image forming device] In this embodiment, a tandem type full-color printer using an intermediate transfer method will be described as an example of the image forming apparatus 1. The image forming apparatus 1 includes a device main body 10, a recording material feeding section (not shown), an image forming section 40, a recording material discharging section (not shown), a control section 30, and an operation section 70 (see FIG. 2).

[0012] Inside the device main body 10, there are provided a temperature sensor 71 (see FIG. 2) capable of detecting the temperature inside the device, and a humidity sensor 72 (see FIG. 2) capable of detecting the humidity inside the device. The image forming device 1 can form a four-color full-color image on a recording material in response to an image signal from an image reading unit 80, a host device such as a personal computer, or an external device such as a digital camera or a smartphone. The recording material S is a material on which a toner image is formed, and specific examples include sheet materials such as plain paper, a synthetic resin sheet that is a substitute for plain paper, cardboard, and an overhead projector sheet.

[0013] The image forming section 40 is capable of forming an image on the recording material S fed from the recording material feeding section based on image information. The image forming section 40 includes image forming units 50y, 50m, 50c, and 50k, toner bottles 41y, 41m, 41c, and 41k, exposure devices 42y, 42m, 42c, and 42k, an intermediate transfer unit 44, a secondary transfer device 45, and a fixing section 46.

[0014] The image forming apparatus 1 of this embodiment is compatible with full color, and multiple image forming units 50y, 50m, 50c, and 50k are provided separately with the same configuration for each of the four colors, yellow (y), magenta (m), cyan (c), and black (k). For this reason, in FIG. 1, the configurations of the four colors are shown with the same reference numerals followed by a color identifier, but in the following description, the configuration of the image forming unit 50y may be used as a representative example. Note that this image forming apparatus 1 can also form a monochromatic or multi-color image, such as a monochromatic black image, by using image forming units 50 for a desired monochromatic color or for some of the four colors.

[0015] The image forming unit 50y includes a photosensitive drum 51y as an image carrier that carries a toner image and moves, a charging roller 52y as a charging device, a developing device 20y, a pre-exposure device 54y, and a cleaning device equipped with a cleaning blade 55y. The image forming unit 50y is integrated as a process cartridge and is configured to be detachable from the apparatus main body 10, and forms a toner image on an intermediate transfer belt 44b described later.

[0016] The photosensitive drum 51y is rotatable and carries an electrostatic image used for image formation. In this embodiment, the photosensitive drum 51y is formed in a cylindrical shape with an outer diameter of 30 mm, and is a negatively charged organic photoconductor (OPC). The photosensitive drum 51y is rotated by a motor (not shown) in the direction of the arrow at a predetermined process speed (circumferential speed). The photosensitive drum 51y has an aluminum cylinder as a base, and has three layers as surface layers on its surface, namely, an undercoat layer, a photocharge generation layer, and a charge transport layer, which are sequentially coated and laminated.

[0017] The charging roller 52y is a rubber roller that comes into contact with the surface of the photosensitive drum 51y and rotates in response to the rotation, uniformly charging the surface of the photosensitive drum 51y. A charging bias power supply 73 (see FIG. 2) is connected to the charging roller 52y. The charging bias power supply 73 applies a charging bias to the charging roller 52y, and charges the photosensitive drum 51y via the charging roller 52y. The exposure device 42y is a laser scanner that emits laser light according to image information of the separated colors output from the control unit 30, and forms an electrostatic image on the photosensitive drum 51y.

[0018] The developing device 20y develops the electrostatic image formed on the photosensitive drum 51y by applying a developing bias with toner to form a toner image. The developing device 20y has a developing sleeve 24y as a developer carrier. The developing device 20y contains the developer supplied from the toner bottle 41y and develops the electrostatic image formed on the photosensitive drum 51y.

[0019] The developing sleeve 24y is made of a non-magnetic material such as aluminum or non-magnetic stainless steel, and is made of aluminum in this embodiment. A roller-shaped magnet roller is fixedly installed inside the developing sleeve 24y in a non-rotating state relative to the developing container. The developing sleeve 24y carries a developer having a non-magnetic toner and a magnetic carrier, and transports the developer to a developing area facing the photosensitive drum 51y. A developing bias power supply 74 (see FIG. 2) is connected to the developing sleeve 24y. The developing bias power supply 74 applies a developing bias to the developing sleeve 24y to develop the electrostatic image formed on the photosensitive drum 51y.

[0020] The toner image developed on the photosensitive drum 51y is primarily transferred to the intermediate transfer belt 44b of the intermediate transfer unit 44. After the primary transfer, the surface of the photosensitive drum 51y is neutralized by a pre-exposure device 54y. The cleaning blade 55y is of a counter blade type and is in contact with the photosensitive drum 51y with a predetermined pressing force. After the primary transfer, the toner remaining on the photosensitive drum 51y that has not been transferred to the intermediate transfer belt 44b is removed by the cleaning blade 55y provided in contact with the photosensitive drum 51y, and prepared for the next image forming process.

[0021] The intermediate transfer unit 44 includes a driving roller 44a, a driven roller 44d, a secondary transfer inner roller 45a as an inner roller, an intermediate transfer belt 44b stretched around these rollers (tension rollers), and primary transfer rollers 47y, 47m, 47c, 47k. The intermediate transfer belt 44b as an image carrier and intermediate transfer body forms primary transfer sections 48y, 48m, 48c, 48k between the photosensitive drums 51y, 51m, 51c, 51k, and moves around (i.e., rotates) while carrying a toner image. The driven roller 44d is a tension roller that controls the tension of the intermediate transfer belt 44b to a constant level. A force is applied to the driven roller 44d by a biasing force of a biasing spring (not shown) so as to push the intermediate transfer belt 44b toward the front side, and a tension of about 2 to 5 kgf is applied in the conveying direction of the intermediate transfer belt 44b by this force.

[0022] The primary transfer rollers 47y, 47m, 47c, and 47k are disposed facing the photosensitive drums 51y, 51m, 51c, and 51k, respectively, via the intermediate transfer belt 44b. The primary transfer roller 47y is disposed with the intermediate transfer belt 44b sandwiched between it and the photosensitive drum 51y, and a primary transfer voltage is applied to the primary transfer roller 47y, whereby the toner image formed on the surface of the photosensitive drum 51y is primarily transferred to the intermediate transfer belt 44b at the primary transfer section 48y. A primary transfer power supply 75y is connected to the primary transfer power supply 75y. A voltage detection sensor 75ay for detecting an output voltage and a current detection sensor 75by for detecting an output current are connected to the primary transfer power supply 75y (see FIG. 2).

[0023] In addition, primary transfer power sources 75y, 75m, 75c, and 75k are provided for the primary transfer rollers 47y, 47m, 47c, and 47k, respectively, and the primary transfer voltages applied to the primary transfer rollers 47y, 47m, 47c, and 47k can be individually controlled.

[0024] The primary transfer roller 47y has an outer diameter of, for example, 15 to 20 mm, and includes an elastic layer of ion conductive foamed rubber (NBR rubber) and a core metal. 5 ~1×10 8 The roller used is Ω (measured at N / N (23°C, 50% RH), 2 kV applied). The same is true for the other primary transfer rollers 47m, 47c, and 47k.

[0025] The intermediate transfer belt 44b is rotatable and rotates at a predetermined speed in the direction of the arrow. The intermediate transfer belt 44b contacts the photosensitive drums 51y, 51m, 51c, and 51k to form primary transfer portions 48y, 48m, 48c, and 48k between the intermediate transfer belt 44b and the photosensitive drums 51y, 51m, 51c, and 51k. A primary transfer voltage is applied from a primary transfer power source 75y, 75m, 75c, and 75k (see FIG. 2) to the primary transfer portions 48y, 48m, 48c, and 48k, and the toner images formed on the photosensitive drums 51y, 51m, 51c, and 51k are primarily transferred at the primary transfer portion 48. By applying a positive polarity primary transfer voltage to the intermediate transfer belt 44b by the primary transfer rollers 47y, 47m, 47c, and 47k, the toner images having negative polarity on the photosensitive drums 51y, 51m, 51c, and 51k are sequentially transferred in a multiplicity onto the intermediate transfer belt 44b.

[0026] The intermediate transfer belt 44b is an endless belt having a three-layer structure consisting of a base layer, an elastic layer, and a surface layer from the back side. The resin material constituting the base layer is a resin such as polyimide or polycarbonate, or a material obtained by adding an appropriate amount of carbon black as an antistatic agent to various rubbers, and the thickness of the base layer is 0.05 to 0.15 [mm]. The elastic material constituting the elastic layer is a material obtained by adding an appropriate amount of an ion conductive agent to various rubbers such as urethane rubber or silicone rubber, and the thickness of the elastic layer is 0.1 to 0.500 [mm].

[0027] The material constituting the surface layer is a resin such as fluororesin, which reduces the adhesion of the toner to the surface of the intermediate transfer belt 44b and makes it easier for the toner to be transferred to the recording material S at the secondary transfer portion N, and has a thickness of 0.0002 to 0.020 mm. In this embodiment, the surface layer uses, as a base material, one type of resin material such as polyurethane, polyester, epoxy resin, etc., or two or more types of elastic materials such as elastic rubber, elastomer, butyl rubber, etc., for example. Then, the surface layer is formed by dispersing one or more types of powder or particles such as fluororesin, or particles with different particle sizes, as a material that reduces surface energy and increases lubricity, on this base material.

[0028] In the present embodiment, the intermediate transfer belt 44b has a volume resistivity of 5×10 8 ~1×10 14 [Ω·cm] (23°C, 50% RH), and the hardness is 60-85° (23°C, 50% RH) in MD1 hardness. The static friction coefficient is 0.15-0.6 (23°C, 50% RH, HEIDON type 94i). In this embodiment, a three-layer structure is used, but a single layer of a material equivalent to the above-mentioned base layer may also be used.

[0029] The secondary transfer device 45 includes a secondary transfer inner roller 45a as an inner roller, and a secondary transfer outer roller 45b as an outer roller and a transfer member. The secondary transfer inner roller 45a contacts the inner surface of the intermediate transfer belt 44b to stretch the intermediate transfer belt 44b, and is disposed opposite the secondary transfer outer roller 45b via the intermediate transfer belt 44b. A secondary transfer power source 76 is connected to the secondary transfer outer roller 45b. A voltage detection sensor 76a that detects the output voltage and a current detection sensor 76b that detects the output current are connected to the secondary transfer power source 76 (see FIG. 2).

[0030] The secondary transfer power source 76 applies a DC voltage to the secondary transfer outer roller 45b as a secondary transfer voltage. The secondary transfer outer roller 45b comes into contact with the intermediate transfer belt 44b to form a secondary transfer portion N between the intermediate transfer belt 44b and the secondary transfer outer roller 45b. When a secondary transfer voltage of a polarity opposite to that of the toner is applied to the secondary transfer portion N, the secondary transfer outer roller 45b secondarily transfers the toner images transferred to the intermediate transfer belt 44b and carried thereon, all at once, to the recording material S supplied to the secondary transfer portion N. The secondary transfer power source 76 may be connected to the secondary transfer inner roller 45a. That is, the secondary transfer power source 76 applies a secondary transfer voltage to the secondary transfer inner roller 45a or the secondary transfer outer roller 45b to transfer the toner image from the intermediate transfer belt 44b to the recording material S.

[0031] In this embodiment, the core metal of the secondary transfer inner roller 45a is connected to a ground potential. When the recording material S is supplied to the secondary transfer device 45, in this embodiment, a secondary transfer voltage that is constant-voltage controlled and has a polarity opposite to that of the toner image is applied to the secondary transfer outer roller 45b. For example, a secondary transfer voltage of 1 to 7 kV is applied, and a current of 40 to 120 μA is passed, so that the toner image on the intermediate transfer belt 44b is secondarily transferred to the recording material S.

[0032] The secondary transfer outer roller 45b has an outer diameter of, for example, 20 to 25 mm, and includes an elastic layer of ion conductive foamed rubber (NBR rubber) and a core metal. 5 ~1×10 8 A roller of Ω (N / N (23℃, 50% RH) measurement, 2 kV applied) is used.

[0033] The intermediate transfer unit 44 also has a belt cleaning device 60. The belt cleaning device 60 removes toner and other deposits remaining on the intermediate transfer belt 44b after the secondary transfer process. In the illustrated example, the belt cleaning device 60 is configured to include two cleaning units 61 and 62 to which voltages of different polarities are applied. The cleaning units 61 and 62 each include a fur brush that rotates in contact with the intermediate transfer belt 44b, and a recovery roller that recovers toner deposited on the fur brush. Voltages of different polarities are applied to the fur brushes of the cleaning units 61 and 62, respectively, to remove the residual toner on the intermediate transfer belt 44b. The belt cleaning device may include a cleaning blade that contacts the intermediate transfer belt 44b to remove the residual toner and the like.

[0034] The fixing section 46 includes a fixing roller 46a and a pressure roller 46b. The recording material S is sandwiched between the fixing roller 46a and the pressure roller 46b and conveyed, so that the toner image transferred to the recording material S is heated and pressurized, and fixed to the recording material S. The temperature of the fixing roller 46a is detected by a fixing temperature sensor 77 (see FIG. 2). After fixing, the recording material discharge section discharges the recording material S conveyed from the discharge path, for example, from a discharge outlet and stacks it on a discharge tray. In addition, between the fixing section 46 and the discharge outlet, a reversing conveying path (not shown) is provided that can turn over the recording material S after fixing and pass it through the secondary transfer device 45 again. By operating the reversing conveying path, it is possible to form images on both sides of one sheet of recording material.

[0035] At the top of the device main body 10, there are disposed an automatic document feeder 81 that automatically feeds a recording material (original) on which an image has been formed to the image reading unit 80, and an image reading unit 80 that reads the image on the recording material S fed by the automatic document feeder 81. This image reading unit 80 is configured to illuminate the original placed on a platen glass 82 with a light source (not shown) and to obtain density data of the image on the original with an image reading element (not shown).

[0036] As shown in Fig. 2, the control unit 30 as a control means is configured by a computer and can control each component of the image forming apparatus 1. The control unit 30 includes, for example, a CPU 31, a ROM 32 that stores programs for controlling each component, a RAM 33 that temporarily stores data, and an input / output circuit (I / F) 34 that inputs and outputs signals to and from the outside. The CPU 31 is a microprocessor that is responsible for the overall control of the image forming apparatus 1, and is the main body of the system controller. The CPU 31 is connected to the recording material feeding unit, the image forming unit 40, the recording material discharging unit, and the operation unit 70 via the input / output circuit 34, and exchanges signals with each unit and controls the operation. The ROM 32 stores an image formation control sequence for forming an image on the recording material S, and the like.

[0037] The control unit 30 is connected to a charging bias power supply 73, a developing bias power supply 74, primary transfer power supplies 75y, 75m, 75c, and 75k, and a secondary transfer power supply 76, each of which is controlled by a signal from the control unit 30. The control unit 30 is also connected to a temperature sensor 71, a humidity sensor 72, a voltage detection sensor 76a and a current detection sensor 76b of the secondary transfer power supply 76, and a fixing temperature sensor 77. The control unit 30 is also connected to voltage detection sensors 75ay, 75am, 75ac, and 75ak and current detection sensors 75by, 75bm, 75bc, and 75bk of the primary transfer power supplies 75y, 75m, 75c, and 75k. Signals detected by each sensor are input to the control unit 30. The temperature sensor 71 and the humidity sensor 72 constitute an environment detection unit 78 that can detect values ​​related to temperature and humidity.

[0038] The operation unit 70, which serves as an input unit and a change unit, includes an operation button and a display unit 70a consisting of a liquid crystal panel or the like. A user can execute an image forming job by operating the operation unit 70, and the control unit 30 receives a signal from the operation unit 70 and operates various devices of the image forming apparatus 1. An image forming job is a series of operations for forming an image on a recording material, which is executed based on a command from the operation unit 70 or a connected external device.

[0039] In this embodiment, the control unit 30 has an image formation preparation processor 31a, an ATVC control processor 31b, and an image formation processor 31c. The control unit 30 also has a primary transfer voltage storage / calculation unit 31d, a cleaning voltage storage / calculation unit 31e, a secondary transfer voltage storage / calculation unit 31f, an image formation counter storage / calculation unit 31g, and a timer storage / calculation unit 31h. These processing units and storage / calculation units may be provided as part of the CPU 31 or the RAM 33. The control unit 30 can switch between a multi-color mode and a single-color mode. In the multi-color mode, a primary transfer voltage is applied to a plurality of primary transfer units 48y, 48m, 48c, and 48k to form an image in multiple colors. In the monochrome mode, a primary transfer voltage is applied to only one primary transfer portion (for example, 48k) among the multiple primary transfer portions 48y, 48m, 48c, and 48k to form a monochrome image.

[0040] Next, the image forming operation in the image forming apparatus 1 configured as above will be described. When the image forming operation is started, first, the photosensitive drum 51y rotates and the surface is charged by the charging roller 52y. Then, the exposure device 42y emits laser light to the photosensitive drum 51y based on image information, and an electrostatic latent image is formed on the surface of the photosensitive drum 51y. The developing device 20y develops this electrostatic latent image with toner and visualizes it as a toner image. Next, the toner image on the photosensitive drum 51y is primarily transferred to the intermediate transfer belt 44b. Such an operation is performed in the image forming units of other colors, and toner images of multiple colors are primarily transferred onto the intermediate transfer belt 44b in a superimposed manner.

[0041] Meanwhile, in parallel with this toner image forming operation, a recording material S is supplied, and is transported to a secondary transfer device 45 in time with the toner image on the intermediate transfer belt 44b. Then, in a secondary transfer section N, the toner image is transferred from the intermediate transfer belt 44b to the recording material S. The recording material S onto which the toner image has been transferred is transported to a fixing section 46, where the unfixed toner image is heated and pressurized to be fixed onto the surface of the recording material S, and then discharged from the apparatus main body 10.

[0042] [ATVC control] Currently, various kinds of recording materials are used to increase the added value of the final product. They can be roughly divided into differences in surface smoothness, such as fine paper and coated paper, and differences in resistance value of paper due to paper thickness and filler. The optimal value of the secondary transfer voltage applied to the transfer member to transfer the toner image to the recording material varies depending on the smoothness and resistance value of the recording material, so in order to obtain a good transfer image, it is required to select an optimal voltage value according to the recording material used. In addition, since the resistance value of the recording material changes significantly depending on the moisture contained in the surroundings, it is required to select a value that takes into account the environment (temperature, humidity) in which the recording material is used, even when the same recording material is used. If the voltage output at the transfer section is not appropriate for the recording material, image defects at the transfer section, such as low image density and whiteout, are likely to occur. In order to apply the optimal secondary transfer voltage according to the type of recording material and the environment in which the recording material is used, in this embodiment, the secondary transfer voltage applied to the secondary transfer section N during image formation is set by ATVC control (Active Transfer Voltage Control).

[0043] The ATVC control as a transfer voltage setting mode is a mode in which a plurality of different first transfer voltages (second test voltages) are applied to the secondary transfer outer roller 45b when there is no recording material at the secondary transfer portion N, and the current is detected by the current detection sensor 76b at each transfer voltage to obtain the relationship between the transfer voltage and the current. That is, in the ATVC control, when the recording material S is not passing through the secondary transfer portion N, a plurality of constant voltages are applied to the secondary transfer outer roller 45b, and the current value flowing through the secondary transfer outer roller 45b at that time is measured. Then, the voltage-current characteristic is obtained, and based on this, a voltage corresponding to a target current value required for transferring a toner image during image formation is interpolated. Furthermore, the voltage value obtained by adding the recording material's share voltage to that voltage is set as the transfer voltage value used during image formation. The target transfer current value and the recording material's share voltage are set according to table data that is preset according to the temperature and humidity in the environment in which the device is placed.

[0044] The flow of such ATVC control will be described in detail with reference to Fig. 3. When the control unit 30 acquires job information from the operation unit 70 or an external device (not shown), it starts the operation of the job (S1). The control unit 30 writes the job information, such as image information and recording material information, to the RAM 33 (S2). Next, the control unit 30 acquires environmental information (values ​​detected by the environmental detection unit 78) detected by the temperature sensor 71 and humidity sensor 72 (S3). In addition, the ROM 32 serving as a storage unit stores information indicating the correlation between the environmental information and a target transfer current Itarget for transferring the toner image on the intermediate transfer belt 44b onto the recording material S.

[0045] Based on the environmental information read in S3, the control unit 30 obtains the target transfer current Itarget corresponding to the environment from the data showing the relationship between the environmental information and the target transfer current Itarget, and writes this to the RAM 33 (S4). The reason why the target transfer current Itarget is changed according to the environmental information is because the charge amount of the toner changes depending on the environment. The data showing the relationship between the environmental information and the target transfer current Itarget is obtained in advance by experiments, etc.

[0046] Next, the control unit 30 obtains information on the electrical resistance of the secondary transfer unit N by ATVC control before the toner image on the intermediate transfer belt 44b and the recording material S onto which the toner image is transferred reach the secondary transfer unit N (S5). That is, in a state in which the secondary transfer outer roller 45b and the intermediate transfer belt 44b are in contact with each other, a plurality of levels of predetermined voltages are supplied from the secondary transfer power source 76 to the secondary transfer outer roller 45b. Then, the current value when the predetermined voltage is being supplied is detected by the current detection sensor 76b, and the relationship between the voltage and the current (voltage-current characteristic) is obtained. This voltage-current characteristic changes depending on the electrical resistance of the secondary transfer unit N.

[0047] Next, the control unit 30 determines the voltage value to be applied from the secondary transfer power source 76 to the outer secondary transfer roller 45b (S6). That is, the control unit 30 determines the voltage value Vb required to flow the target transfer current Itarget in a state where no recording material S is present at the secondary transfer portion N, based on the target transfer current Itarget written in the RAM 33 in S4 and the relationship between the voltage and current determined in S5.

[0048] The ROM 32 also stores information for calculating the recording material voltage Vp. The recording material voltage Vp is held as table data indicating the relationship between the type of recording material (e.g., paper types such as plain paper, thick paper, and thin paper) for each basis weight category of the recording material S, the moisture content of the atmosphere, and the recording material voltage Vp. The table data for calculating the recording material voltage Vp is obtained by selecting a representative brand of recording material for each basis weight category and conducting experiments in advance for the recording material. The control unit 30 can calculate the moisture content of the atmosphere based on the environmental information (information on temperature and humidity) detected by the temperature sensor 71 and the humidity sensor 72. The control unit 30 calculates the recording material voltage Vp from the table data based on the job information acquired in S1 and the environmental information acquired in S3.

[0049] Furthermore, when an adjustment value is set by the adjustment mode of the secondary transfer voltage described later, the control unit 30 calculates the adjustment amount ΔV. Then, the control unit 30 calculates Vb+Vp+ΔV by adding Vb, Vp, and ΔV as the secondary transfer voltage Vtr, which is the voltage to be applied from the secondary transfer power source 76 to the outer secondary transfer roller 45b when the recording material S passes through the secondary transfer portion N, and writes the result in the RAM 33.

[0050] Next, the recording material S is sent to the secondary transfer unit N, and image formation is performed while applying the secondary transfer voltage Vtr (S7). Thereafter, the control unit 30 repeats S7 until all images of the job have been transferred onto the recording material S and output (S8).

[0051] [Secondary transfer voltage adjustment mode] As described above, the use of ATVC control allows the transfer voltage to be set based on the type and environment of the recording material. However, there are many types of recording materials in circulation, and even if the paper type is the same in the same basis weight category, the resistance may differ depending on the paper brand. In this way, when using recording materials with various resistance values, the optimal transfer voltage was often set using a service mode or user mode, which allows the adjustment value of the image formation conditions to be changed. That is, in this mode, there were many cases in which the user searched for an appropriate secondary transfer voltage while actually outputting an image while changing the output value of the secondary transfer voltage. However, the adjustment using the service mode or user mode was a task that was performed by stopping the output operation of the device main body, and required a recording material for adjustment in addition to the recording material for the original output, which placed a burden on the user. Therefore, in this embodiment, a configuration is provided with the following secondary transfer voltage adjustment mode.

[0052] The adjustment mode of the secondary transfer voltage will now be described. For example, depending on the type of recording material used by the user, the resistance value of the recording material may differ from the resistance value of the representative recording material stored in the table data described above, so that optimal transfer may not be possible when the recording material distribution voltage Vp in the table data is used.

[0053] More specifically, when the toner on the intermediate transfer belt 44b is transferred to the recording material, in order to prevent the generation of defective images, it is necessary to apply an optimal secondary transfer voltage Vtr. If the resistance value of the recording material used by the user is higher than the resistance value stored as table data, the current required to transfer the toner may be insufficient, resulting in the generation of transfer-missing images. For this reason, in this case, the secondary transfer voltage Vtr must be set high.

[0054] In addition, if the moisture content of the recording material is reduced and discharge phenomena are likely to occur, there is a possibility that defective images such as blank images will be produced due to abnormal discharge. In this case, the secondary transfer voltage Vtr must be set low.

[0055] Therefore, in order to obtain the above-mentioned optimum adjustment amount ΔV for each recording material in order to set the secondary transfer voltage Vtr appropriately so that no defective images are generated, the secondary transfer voltage adjustment mode is implemented. In the secondary transfer voltage adjustment mode, a semi-automatic adjustment mode can be implemented as a selection mode including a test chart output mode.

[0056] [Test chart output mode] In the test chart output mode, a predetermined test image is transferred from the intermediate transfer belt 44b to a recording material with a plurality of different transfer voltages (test voltages, first test voltages), and the recording material is output. That is, the test chart output mode in the adjustment mode is a mode in which a plurality of different test voltages are applied to the outer secondary transfer roller 45b, a predetermined test image is transferred from the intermediate transfer belt 44b to the recording material, and a test chart for adjusting the transfer voltage set during image formation is output.

[0057] Specifically, a recording material is output on which an adjustment image chart as shown in Figures 4 and 5 is formed. The adjustment image chart shown in Figures 4 and 5 has pattern images of solid density images (blackened areas) and halftone density images (hatched areas) formed. Each pattern image is formed while changing the transferability by switching the output value of the secondary transfer voltage Vtr for each pattern image.

[0058] Then, based on a plurality of predetermined test images on the output recording material, the transfer voltage during image formation is adjusted using a transfer voltage selected from a plurality of different transfer voltages. For example, the user selects a transfer voltage corresponding to an image that is determined to be optimal from a plurality of predetermined test images output on the recording material by visual inspection, and adjusts the secondary transfer voltage Vtr used during subsequent image formation using the selected transfer voltage. That is, the user selects a pattern image that provides optimal transferability from the adjustment image chart, and the control unit 30 determines the adjustment amount ΔV.

[0059] On the other hand, in this embodiment, a semi-automatic adjustment mode (selection mode) can be executed in which an appropriate pattern image is selected using the image reading unit 80 as a density detection unit. In the semi-automatic adjustment mode, the image reading unit 80 detects a plurality of images (predetermined test images) corresponding to a plurality of test voltages on the adjustment image chart (on the test chart) output in the test chart output mode. Then, based on the detection result, an adjustment value for a transfer voltage that is preset according to a predetermined selection criterion is automatically selected. That is, in a device having a semi-automatic adjustment mode using the image reading unit 80, the output adjustment image chart is read by the image reading unit 80, and an adjustment amount ΔV that results in an optimal transfer setting is automatically selected from the acquired density data. A detailed explanation of the semi-automatic adjustment mode will be given later.

[0060] The image chart for adjustment will be described in more detail with reference to Fig. 4 and Fig. 5. In the adjustment mode of the secondary transfer voltage of this embodiment, an image chart is used that includes a pattern image in which a solid density image of the secondary color blue, a solid density image of the single color black, and a halftone density image of the single color black are arranged, which are suitable for judging the transferability, as shown in Fig. 4. Note that since it is difficult to judge if the size is small, the image size is preferably 10 mm square or more, and more preferably 25 mm square or more.

[0061] Next to each pattern image, a value corresponding to the adjustment amount ΔV of the secondary transfer voltage Vtr applied to that pattern image is written. That is, on the recording material output in the adjustment mode, values ​​related to a plurality of different transfer voltages are also printed in correspondence with a plurality of predetermined test images. A voltage value in which the adjustment amount ΔV of the secondary transfer voltage Vtr Vb+Vp+ΔV set by the above-mentioned ATVC control is 0V is applied to the pattern image with this value being 0. In addition, in this embodiment, this adjustment amount ΔV is calculated with 100V as "1", and for example, when the adjustment amount ΔV is +300V, the adjustment amount ΔV is written as "+3", and a secondary transfer voltage Vtr of Vb+Vp+300V is applied to the pattern image. That is, a plurality of first test voltages in the test chart output mode are set on the high voltage side and the low voltage side with the transfer voltage set by the ATVC control as the center value.

[0062] The maximum recording material size that can be used with the device is 13 inches x 19.2 inches, but even if the adjustment image chart is formed on a recording material smaller than the maximum size, the adjustment image chart is output to fit the recording material with the center of the leading edge as the reference. For example, an A3 size chart is output by cutting it to a size of 292 x 415 mm. In this embodiment, an adjustment image chart with 11 pattern images arranged thereon is used as an example, but this is not limited to this.

[0063] The size of the pattern image is a 25.7 mm square for the secondary color blue and single color black (solid density image), and the gray (halftone density image) at the end is 25.7 mm in the transport direction and extends to the end of the recording material in the width direction perpendicular to the transport direction. The interval between the pattern images in the transport direction is 9.5 mm, and the secondary transfer voltage Vtr is switched between them. The 11 pattern images in the transport direction are 387 mm so that they fit within the 415 mm of A3 size. In addition, pattern images are not formed at the leading and trailing ends of the recording material, especially when thick or thin paper is used, because there is a possibility that another defective image that tends to occur only at the leading and trailing ends may occur. When a recording material with a small width in the longitudinal direction is selected, the width of the halftone density image at the end is reduced.

[0064] When using a recording material whose length in the transport direction is shorter than A3 size, an adjustment image chart like the one shown in Figure 5 is used. The overall size of the adjustment image chart is 13 inches x 210 mm, and can accommodate recording materials from A5 portrait feed to lengths shorter than A3. The width of the half-tone density image shortens according to the length of the recording material in the width direction, the output length of the five pattern images in the transport direction is 167 mm, and the trailing margin lengthens according to the length of the recording material. Since only five pattern images can be printed on one sheet, they are output on two sheets in order to increase the number of pattern images.

[0065] [Comparative Example] The secondary transfer voltage adjustment mode including the semi-automatic adjustment mode in the comparative example will be described with reference to the flow chart in Fig. 6. On the secondary transfer voltage adjustment mode screen, the user selects the type and size of the recording material to be adjusted, and whether it is single-sided or double-sided, from the operation unit 70 (S101). In this example, the basis weight is 150 g / m 2 The recording material setting on the device is Thick Paper 2 (121-152 g / m 2 This section describes how to adjust the output and settings for the front side of the A3-sized recording material.

[0066] First, after selecting cardboard 2, A3 size, single-sided as the type of recording material to be adjusted, the user selects the test page output button from the operation unit 70 on the <adjustment of secondary transfer voltage> screen as shown in FIG. 7 (S102). The image forming apparatus starts the image forming operation of the test page, executes ATVC control during pre-rotation of this image forming operation, and acquires the voltage-current characteristics of the secondary transfer unit (S103). Note that the pre-rotation is a period during which the photosensitive drum starts rotating as a preparation operation before the image forming operation, and various voltages are sequentially started up and various voltages are adjusted. Also, the test page is a page on which an adjustment image chart including the above-mentioned multiple pattern images is formed.

[0067] Next, the secondary transfer voltage Vtr (output value) to be applied to the pattern image in the adjustment image chart is calculated, and output while switching in the recording material (S104). The calculation method of this output value will be specifically described using the explanatory diagram of FIG. 8 as an example. Note that the following (1) to (2) correspond to (1) to (2) in FIG. 8.

[0068] (1) First, a voltage value Vb (e.g., 2700 V) required to pass a target transfer current Itarget (e.g., 37 μA) according to the conditions selected in S101 is calculated from the voltage-current characteristics of the secondary transfer unit obtained by ATVC control. Also, a recording material shared voltage Vp (e.g., 1500 V) is referenced from table data.

[0069] (2) The adjustment value ΔV is set to 0 V, and the secondary transfer voltage Vtr (e.g., 4200 V) is calculated as Vb (2700 V) + Vp (1500 V) + ΔV (0 V), and the secondary transfer voltage Vtr at this point is set as the central value Vtr(def). In addition, next to the pattern image of the central value Vtr(def), the value corresponding to the adjustment amount ΔV is marked as 0.

[0070] In the illustrated example, the secondary transfer voltage Vtr corresponding to the numerical value written next to each pattern image is "1" (numerical value) for 100V, and the secondary transfer voltage Vtr corresponding to each numerical value from -5 to +5 is switched and applied for each pattern image in the recording material. That is, the voltage is switched and applied corresponding to the numerical value, 3700V (numerical value -5) and 4700V (numerical value +5), relative to the central value 4200V (def: numerical value 0) obtained by ATVC control, and output.

[0071] The outputted adjustment image chart is set in the image reading unit 80 by the user, and reading is started on the display screen of the operation unit 70 (S105). As a result, density data of each pattern image of the adjustment image chart, that is, secondary color blue solid, monochrome black solid, and monochrome black halftone, is obtained (S106).

[0072] Based on the density data obtained above, a pattern image with optimal transferability (value -5 to +5) and an adjustment value ΔV at that time are obtained according to the following (a) and (b) as predetermined selection criteria (S107). (a) From the data acquired in S106, a pattern image in which the secondary color blue solid and the monochrome black solid have stable density is extracted. (b) Among the secondary blue solid colors extracted in (a), the smallest adjustment value (lowest voltage) is selected.

[0073] The pattern image is output by varying the secondary transfer voltage Vtr from the center value (def) under ATVC control to the low and high voltage sides. In this case, if the secondary transfer voltage Vtr is lowered, a sufficient amount of toner cannot be transferred to the recording material S in a portion with a large amount of toner, such as a solid blue secondary color, and a transfer-void image occurs. Conversely, if the secondary transfer voltage Vtr is increased, the toner polarity is partially reversed and returned to the intermediate transfer belt 44b due to abnormal discharge in a portion with a small amount of toner, such as a single-color halftone, and a dotted blank image occurs.

[0074] In the semi-automatic adjustment mode of the comparative example, the setting value is automatically selected based on the above-mentioned selection criteria (a) and (b) so as to prevent the occurrence of the dotted white image in the halftone portion. Also, in the comparative example, the adjustment image chart is read by the image reading unit 80, and then the value automatically selected in (b) (front surface: +1 in the illustrated example) is displayed at a predetermined position on the display screen shown in Fig. 7. The user checks the output adjustment image chart and judges whether there is a problem with the transferability of the pattern image corresponding to the displayed value (S108).

[0075] If there are no problems (YES in S108), select "OK" on the screen in Figure 7 to set the paper size to Thick Paper 2 (121 to 152 g / m 2 ) (S109). Thereafter, when the user uses recording materials of this category, this adjustment value ΔV is reflected.

[0076] On the other hand, if in S108 the user wishes to set a value larger or smaller than the automatically selected value (NO in S108), the user can manually change the adjustment value by changing the numerical value with the + and - buttons on the screen in FIG. 7 (S110). This allows the user to adjust the transferability of the desired pattern image. After manually changing the adjustment value, by selecting "OK" on the screen in FIG. 7, the transferability of the pattern image is set to the desired transferability for cardboard 2 (121 to 152 g / m 2 ) is reflected in the setting value on the front side (S109).

[0077] In the case of the comparative example described above, if the user wishes to change the automatically selected value in the semi-automatic adjustment mode, the user must manually re-input the automatically selected setting value each time after the image reading unit 80 reads the adjustment image chart. If the user is required to manually re-change the adjustment value each time the adjustment mode is executed, the transfer voltage adjustment work takes time, and the work efficiency decreases. Therefore, in this embodiment, the semi-automatic adjustment mode is performed as follows.

[0078] [Semi-automatic adjustment mode of this embodiment] The secondary transfer voltage adjustment mode of this embodiment also has a semi-automatic adjustment mode including a test chart output mode, as in the comparative example described above. However, it is different from the comparative example in that an offset value can be set for the adjustment value automatically selected in the semi-automatic adjustment mode. In other words, the adjustment value can be changed.

[0079] That is, in the semi-automatic adjustment mode of this embodiment, the image reading unit 80 detects a plurality of images (predetermined test images) corresponding to a plurality of test voltages on the adjustment image chart output in the test chart output mode. Then, based on the detection result, an adjustment value for the transfer voltage that is set in advance according to a predetermined selection criterion, that is, set by ATVC control, is automatically selected. The predetermined selection criterion is the same as (a) and (b) described above.

[0080] In this way, the adjustment value selected in the semi-automatic adjustment mode (Settings information) The operation unit 70 can display the correction amount for the adjustment value displayed on the display unit 70a, that is, the offset value (Correction information) It is possible to input the offset value into the control unit 30. Then, in the semi-automatic adjustment mode after the offset value is input through the operation unit 70, the control unit 30 displays the adjustment value selected based on the predetermined selection criterion and the adjustment value based on the offset value. That is, in the semi-automatic adjustment mode, the offset value is automatically reflected in the adjustment value selected based on the predetermined selection criterion.

[0081] In other words, the operation unit 70 can change the above-mentioned adjustment values, and the control unit 30 automatically reflects the change in the adjustment value to the adjustment value selected based on a predetermined selection criterion in the semi-automatic adjustment mode after the adjustment value is changed by the operation unit 70. This will be described in detail below with reference to Figures 9(a) and (b).

[0082] S101 to S109 in FIG. 9A are the same as S101 to S109 in FIG. 6 described above. In S110 in FIG. 6, the automatically selected adjustment value was manually corrected each time. In contrast, in this embodiment, in the semi-automatic adjustment mode, a user mode <Adjustment of secondary transfer voltage, Adjustment of offset value> screen as shown in FIG. 10 is displayed on the display unit 70a. Then, it is possible to input an offset value for the adjustment value (automatically selected value) selected by automatic adjustment (S111 in FIG. 9A).

[0083] For example, if the automatically selected value displayed on the display screen in S108 was "+1", and the user desires a pattern image transferability of +2, the user inputs an offset value of +1 for the automatically selected value on the offset value adjustment screen in FIG. 10 (S111). In the illustrated example, the "+" button is pressed once. As a result, from now on, a value offset by "+1" from the original automatically selected value will be displayed after the adjustment image chart is read. That is, the control unit 30 automatically reflects the offset value inputted on the operation unit 70 in the adjustment value (automatically selected value) automatically selected in the subsequent semi-automatic adjustment mode, and causes the reflected automatically selected value to be displayed on the display unit 70a.

[0084] Specifically, as shown in Fig. 9(b), in the semi-automatic adjustment mode after inputting the offset value described above, an adjustment image chart is printed (S201), and this adjustment image chart is read by the image reading unit 80. At this time, the control unit 30 automatically selects an adjustment value that reflects the offset value described above (S202). Then, returning to S108 in Fig. 9(a), this value is displayed on the display unit 70a.

[0085] In this embodiment, such offset values ​​can be input according to the type of recording material. That is, the operation unit 70 can input an offset value for the adjustment value for each type of recording material (for example, for each paper type). Here, in S101 of FIG. 9A, the user selects the type and size of the recording material to be adjusted, and single-sided or double-sided, from the operation unit 70, but in this embodiment, the above-mentioned offset value is valid only for the recording material selected here. Then, when the semi-automatic adjustment mode is executed for the same type of recording material as the recording material for which the offset value was input, the control unit 30 automatically reflects the above-mentioned offset value in the adjustment value selected according to a predetermined selection criterion. For example, after the setting of the above-mentioned offset value (+1) (for example, the first adjustment), this offset value is applied to each classification of recording material selected in S101 (here, thick paper 2) when the adjustment mode of the secondary transfer voltage is executed. Then, on the adjustment screen of the semi-automatic adjustment mode, a value offset by "+1" from the automatically selected value is always displayed.

[0086] In addition, when the semi-automatic adjustment mode is executed for a recording material of a different type from the recording material for which the offset value was input, the above-mentioned offset value is not automatically reflected in the adjustment value selected based on the predetermined selection criteria.

[0087] In this manner, in the case of this embodiment, when it is desired to correct the adjustment value that is automatically selected in the semi-automatic adjustment mode, the user does not have to manually re-input the adjustment value each time after the automatic adjustment, or the frequency of re-inputting the adjustment value can be reduced, thereby improving the efficiency of the transfer voltage adjustment work.

[0088] <Other embodiments> In the above embodiment, the offset value can be reflected for each type of recording material. However, the offset value may be applied to all types of recording materials. That is, in the semi-automatic adjustment mode after the offset value is inputted by the operation unit 70, the control unit 30 may automatically reflect the offset value to the adjustment value selected based on a predetermined selection criterion regardless of the type of recording material. For example, if the offset value is set to "+1" when the type of recording material is "thick paper 2", the secondary transfer voltage adjustment mode is then executed for "plain paper", and at that time, in the semi-automatic adjustment mode, a value offset by "+1" from the automatically selected value is displayed.

[0089] This eliminates the need to set an offset value for each individual recording material, and allows correction to be made to the automatically selected value in the semi-automatic adjustment mode for all recording materials with a single operation, thereby making it possible to efficiently adjust the transfer voltage.

[0090] In addition, it may be possible to separately select in user mode or service mode whether the offset value for the adjustment value in the semi-automatic adjustment mode is reflected for each type of recording material or for all types of recording material.

[0091] The offset values ​​for the above adjustment values ​​may be reflected separately for each logged-in user. In the above embodiment, the offset values ​​for the above adjustment values ​​can be input on the adjustment screen in the user mode, but the offset values ​​may be input only in the service mode, etc., to limit the users who can input the offset values.

[0092] In the above explanation, the offset value is reflected as it is in the adjustment value, but this is not limited to the above. Based on the previous correction result (offset value), the user may determine that a higher transfer setting is preferred and change the adjustment value to the plus side. For example, if an offset value of "+2" is input on the operation unit 70, a value offset by "+1" may be displayed from the next time onwards. In other words, a value calculated by applying a predetermined coefficient to the offset value may be reflected as the offset value from the next time onwards.

[0093] In the above embodiment, the density detection unit capable of detecting the density of the output image is the image reading unit 80. However, the density detection unit may be a dedicated device capable of reading only density data other than the image reading unit 80, for example, as long as the device is capable of reading density data of the output image. For example, the density detection unit may be a manually operated colorimeter as described in Patent Document 1.

[0094] In the above embodiment, the adjustment of the secondary transfer voltage in the secondary transfer section has been described in the configuration of the intermediate transfer type using the intermediate transfer belt. The present invention is not limited to this, and can also be applied to a configuration of a direct transfer type in which the image is directly transferred from the photosensitive drum to the recording material, and a configuration having, for example, a primary transfer roller using an ion conductive material as a transfer member. That is, the primary transfer roller forms a primary transfer section between the photosensitive drum and the primary transfer roller to transfer the toner image from the photosensitive drum to the recording material. Then, the toner image is transferred from the photosensitive drum to the recording material by applying a primary transfer voltage to the primary transfer section. In such a primary transfer section, the resistance value of the primary transfer roller changes between the initial state and after durability, similar to the above-mentioned secondary transfer section. Therefore, the adjustment of the transfer voltage similar to that in the above embodiment can be applied to the adjustment of the primary transfer voltage.

[0095] Furthermore, the present invention is not limited to the tandem type image forming apparatus 1 using the intermediate transfer method, but may be an image forming apparatus of another method. Also, the present invention is not limited to full color, but may be monochrome or monocolor. Alternatively, the present invention may be embodied in various applications such as printers, various printing machines, copiers, FAX machines, and multifunction machines. [Explanation of symbols]

[0096] 30...Control section 44b: Intermediate transfer belt (image carrier) 45b Secondary transfer outer roller (transfer member) 70... Operation section (input section, change section) 70a...Display section 76 Secondary transfer power supply (power supply) 76b Current detection sensor (current detection section) 78. Environment detection unit 80...Image reading unit (density detection unit)

Claims

1. an image forming unit that forms a toner image; an image carrier that carries a toner image formed by the image forming unit; a transfer member for transferring a toner image from the image carrier to a recording material; a power source that applies a transfer voltage to the transfer member; a density detection unit capable of detecting density information of an image formed on a recording material; A display unit capable of displaying information; a control unit capable of executing an adjustment mode for outputting a test chart for adjusting a transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to a recording material while applying a plurality of different test voltages to the transfer member; An operation unit that allows information to be manually input, The control unit is in the adjustment mode, setting information of a transfer voltage to be set during a transfer period is displayed on the display unit based on a detection result of the test chart detected by the density detection unit, correction information for correcting the setting information displayed on the display unit is acceptable from the operation unit, and a transfer voltage to be set during the transfer period is determined based on the correction information input from the operation unit; The image forming apparatus is configured so that each user can log in. The control unit, during the current adjustment mode, displays on the display unit setting information for the transfer voltage to be set during the transfer period based on the detection result obtained by the density detection unit of the test chart output during the current adjustment mode and the correction information input from the operation unit during the previous adjustment mode, and determines whether or not to display based on the correction information input in the adjustment mode executed last time, depending on the user logged in to the image forming device.

2. an image forming unit that forms a toner image; an image carrier that carries a toner image formed by the image forming unit; a transfer member for transferring a toner image from the image carrier to a recording material; a power source that applies a transfer voltage to the transfer member; a density detection unit capable of detecting density information of an image formed on a recording material; A display unit capable of displaying information; a control unit capable of executing an adjustment mode for outputting a test chart for adjusting a transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to a recording material while applying a plurality of different test voltages to the transfer member; An operation unit that allows information to be manually input, The control unit is in the adjustment mode, setting information of a transfer voltage to be set during a transfer period is displayed on the display unit based on a detection result of the test chart detected by the density detection unit, correction information for correcting the setting information displayed on the display unit is acceptable from the operation unit, and a transfer voltage to be set during the transfer period is determined based on the correction information input from the operation unit; an image forming apparatus characterized in that, during the current adjustment mode, the control unit, when displaying on the display unit setting information for the transfer voltage to be set during the transfer period based on the detection result of the test chart output during the current adjustment mode by the density detection unit and the correction information input from the operation unit during the previous adjustment mode, determines whether or not to display based on the correction information input in the previous adjustment mode, depending on the type of recording material on which the test chart output in the current adjustment mode is formed.

3. an image forming unit that forms a toner image; an image carrier that carries a toner image formed by the image forming unit; a transfer member for transferring a toner image from the image carrier to a recording material; a power source that applies a transfer voltage to the transfer member; a density detection unit capable of detecting density information of an image formed on a recording material; A display unit capable of displaying information; a control unit capable of executing an adjustment mode for outputting a test chart for adjusting a transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to a recording material while applying a plurality of different test voltages to the transfer member; An operation unit that allows information to be manually input, The control unit is in the adjustment mode, setting information of a transfer voltage to be set during a transfer period is displayed on the display unit based on a detection result of the test chart detected by the density detection unit, correction information for correcting the setting information displayed on the display unit is acceptable from the operation unit, and a transfer voltage to be set during the transfer period is determined based on the correction information input from the operation unit; the control unit, during the current adjustment mode, causes the display unit to display setting information of a transfer voltage to be set during a transfer period based on a detection result obtained by detecting, by the density detection unit, the test chart output during the current adjustment mode and the correction information input from the operation unit during the previous adjustment mode; an image forming apparatus characterized in that, when the type of recording material on which the test chart output in the previous adjustment mode was formed was a first type, and the type of recording material on which the test chart output in the current adjustment mode was formed is a second type different from the first type, the control unit displays a transfer voltage to be displayed in the current adjustment mode based on the correction information input in the previous adjustment mode.

4. an image forming unit that forms a toner image; an image carrier that carries a toner image formed by the image forming unit; a transfer member for transferring a toner image from the image carrier to a recording material; a power source that applies a transfer voltage to the transfer member; a density detection unit capable of detecting density information of an image formed on a recording material; A display unit capable of displaying information; a control unit capable of executing an adjustment mode for outputting a test chart for adjusting a transfer voltage, the test chart being formed by transferring a predetermined test image from the image carrier to a recording material while applying a plurality of different test voltages to the transfer member; An operation unit that allows information to be manually input, The control unit is in the adjustment mode, setting information of a transfer voltage to be set during a transfer period is displayed on the display unit based on a detection result of the test chart detected by the density detection unit, correction information for correcting the setting information displayed on the display unit is acceptable from the operation unit, and a transfer voltage to be set during the transfer period is determined based on the correction information input from the operation unit; The control unit, during the current adjustment mode, is capable of selectively determining whether or not to display the transfer voltage based on the correction information input in the previous adjustment mode when displaying setting information for the transfer voltage to be set during the transfer period on the display unit based on the detection result obtained by the density detection unit detecting the test chart output during the current adjustment mode and the correction information input from the operation unit during the previous adjustment mode.

Images