Image forming device and program

Abstract

To suppress deterioration in a charge amount of a second developer.SOLUTION: In a first operation in which an image forming is performed by a first developer held by a first developer holding body 334A and the first developer is conveyed by first conveyance means 338A, the rotation speed of the first developer holding body 334A and a second developer holding body 334B is a first rotation speed, and the conveyance speed of the first conveyance means 338A and second conveyance means 338B is a first conveyance speed. In a second operation in which image forming is performed by a second developer held by the second developer holding body 334B and the second developer is conveyed by the second conveyance means 338B, the rotation speed of the first developer holding body 334A and the second developer holding body 334B is a second rotation speed smaller than the first rotation speed, and the conveyance speed of the first conveyance means 338A is a second conveyance speed smaller than the first conveyance speed, and the conveyance speed of the second conveyance means 338B is larger than the second conveyance speed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus and a program. [Background technology]

[0002] For example, Patent Document 1 discloses an image forming apparatus that is characterized by comprising an image carrier that is rotated and on whose surface an electrostatic latent image corresponding to image information is formed, a color developing means that develops the electrostatic latent image formed on the image carrier while stirring a two-component developer consisting of color toner and carrier by a stirring means, and a transparent developing means that develops the electrostatic latent image formed on the image carrier while stirring a two-component developer consisting of transparent toner and carrier by a stirring means whose stirring capacity is set smaller than that of the stirring means of the color developing means. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-151974 A Summary of the Invention [Problem to be solved by the invention]

[0004] Here, in an image forming apparatus capable of performing a first operation of forming an image with a first developer of one color transported by a first transport means and held by a rotating first developer holder, and a second operation of forming an image with a second developer of another color transported by a second transport means and held by a rotating second developer holder, the configuration is considered in which the rotation speeds of the first developer holder and the second developer holder are lower in the second operation than in the first operation. If the transport speeds of the first transport means and the second transport means are lower in the second operation as the rotation speeds decrease than in the first operation, there is a risk that the second developer, which is less easily charged than the first developer, will be supplied to the second developer holder. The object of the present invention is to suppress a decrease in the charge amount of the second developer when the rotational speed of the first developer holder and the rotational speed of the second developer holder are slower in the second operation than in the first operation, compared to when the transport speed of the second transport means that transports the second developer is slower than in the first operation. [Means for solving the problem]

[0005] The invention described in claim 1 is an image forming apparatus capable of performing a first operation of forming an image with a first developer of one color conveyed by a first conveying means and held by a rotating first developer holder, and a second operation of forming an image with a second developer of another color conveyed by a second conveying means and held by a rotating second developer holder, wherein in the first operation, a rotation speed of the first developer holder and a rotation speed of the second developer holder are a first rotation speed, and the rotation speed of the first developer holder by the first conveying means is a second rotation speed. An image forming apparatus, wherein a developer transport speed and a transport speed of the second developer by the second transport means are a first transport speed, and in the second operation, a rotation speed of the first developer holder and a rotation speed of the second developer holder are a second rotation speed that is smaller than the first rotation speed, a transport speed of the first developer by the first transport means is a second transport speed that is smaller than the first transport speed, and a transport speed of the second developer by the second transport means is a transport speed that is larger than the second transport speed. The invention described in claim 2 is the image forming apparatus described in claim 1, characterized in that the transport of the second developer by the second transport means is performed by a driving source other than the driving source that rotates the second developer holder. The invention described in claim 3 is the image forming apparatus described in claim 1, characterized in that the transport speed of the second developer by the second transport means in the second operation is determined based on the first transport speed. The invention described in claim 4 is the image forming apparatus described in claim 3, characterized in that the transport speed of the second developer by the second transport means in the second operation is the same as the first transport speed. The invention described in claim 5 is the image forming apparatus described in claim 3, characterized in that the transport speed of the second developer by the second transport means in the second operation is slower than the first transport speed. The invention described in claim 6 is the image forming apparatus described in claim 3, characterized in that the transport speed of the second developer by the second transport means in the second operation is greater than the first transport speed. The invention described in claim 7 is the image forming apparatus described in claim 3, characterized in that the conveying speed of the first conveying means and the conveying speed of the second conveying means are not changed between the start and stop of rotation of the first developer holder and the second developer holder. The invention described in claim 8 is the image forming apparatus described in claim 1, characterized in that the transport speed of the second developer by the second transport means in the second operation is determined according to the second developer. The invention described in claim 9 is the image forming apparatus described in claim 8, characterized in that the transport speed of the second developer by the second transport means in the second operation is determined according to information indicating the ease of charging the second developer. The invention described in claim 10 provides an image forming apparatus capable of performing a first operation of forming an image with a first developer of one color conveyed by a first conveying means and held by a rotating first developer holder, and a second operation of forming an image with a second developer of another color conveyed by a second conveying means and held by a rotating second developer holder, the image forming apparatus being configured to include a processor that controls the image forming apparatus and that controls the processor to control a first rotation speed of the first developer holder and the second developer holder, the first rotation speed of the second developer holder, the conveying speed of the first developer by the first conveying means, and and a function of controlling a transport speed of the second developer by the second transport means so that the first transport speed is a first transport speed, and a function of controlling a rotation speed of the first developer holder and the second developer holder so that the rotation speed is a second rotation speed that is smaller than the first rotation speed, a transport speed of the first developer by the first transport means is a second transport speed that is smaller than the first transport speed, and a transport speed of the second developer by the second transport means is a transport speed that is larger than the second transport speed, in the second operation. Effect of the Invention

[0006] According to the invention of claim 1, when the rotational speed of the first developer holder and the rotational speed of the second developer holder are slower in the second operation than in the first operation, the decrease in the charge amount of the second developer can be suppressed compared to when the transport speed of the second transport means that transports the second developer is slower than in the first operation. According to the invention of claim 2, the transport of the second developer by the second transport means can be simplified in configuration compared to a case in which the transport is not performed by a drive source separate from the drive source that rotates the second developer holder. According to the invention of claim 3, the transport speed of the second developer by the second transport means in the second operation can be controlled more simply than in a case where the configuration is not provided in which the transport speed is determined based on the first transport speed. According to the invention of claim 4, the transport speed of the second developer by the second transport means in the second operation can be simplified compared to a case in which the configuration is not provided such that the transport speed is the same as the first transport speed. According to the invention of claim 5, the transport speed of the second developer by the second transport means in the second operation can ensure the charge amount of the second developer compared to a case in which the transport speed is not lower than the first transport speed. According to the invention of claim 6, the transport speed of the second developer by the second transport means in the second operation can ensure the charge amount of the second developer compared to a case where the transport speed is not faster than the first transport speed. According to the invention of claim 7, the rotation speed of the first developer holder and the rotation speed of the second developer holder can be prevented from being unevenly distributed in the first transport means and the second developer in the second transport means, compared to a case in which the configuration is not provided in which the rotation speeds of the first developer holder and the second developer holder are not changed between the start and stop of rotation of the first developer holder and the second developer holder. According to the invention of claim 8, the transport speed of the second developer by the second transport means in the second operation can ensure the charge amount of the second developer compared to a case where the configuration is not determined according to the second developer. According to the invention of claim 9, the transport speed of the second developer by the second transport means in the second operation can ensure the amount of charge of the second developer compared to a case in which the transport speed is not determined according to information indicating the ease of charging the second developer. According to the invention of claim 10, when the rotational speed of the first developer holder and the rotational speed of the second developer holder are slower in the second operation than in the first operation, the decrease in the charge amount of the second developer can be suppressed compared to when the transport speed of the second transport means that transports the second developer is slower than in the first operation. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an image forming apparatus. [Diagram 2] FIG. 2 is a diagram illustrating a developing device of the image forming apparatus. [Diagram 3] 1A and 1B are diagrams illustrating a developing unit of an image forming apparatus according to a first embodiment, where FIG. 1A shows a developing unit and FIG. [Figure 4]FIG. 2 illustrates an example of the hardware configuration of a control unit of the image forming apparatus. [Diagram 5] FIG. 2 is a block diagram illustrating a functional configuration of a control unit according to the first embodiment. [Figure 6] 10 is a flowchart illustrating an example of a processing procedure for speed control of a conveyance unit of a developing unit when a print job is accepted in the first embodiment. [Figure 7] 6 is a table showing an example of the speed of a developing unit according to the first embodiment. [Figure 8] 10A and 10B are diagrams illustrating a developing unit of an image forming apparatus according to a second embodiment, where FIG. 10A shows a developing unit and FIG. [Figure 9] FIG. 11 is a block diagram illustrating a functional configuration of a control unit according to a second embodiment. [Figure 10] 13 is a flowchart illustrating an example of a processing procedure for controlling the speed of a conveyance unit of a developing unit and the conveyance unit of a developing unit when a print job is accepted in the second embodiment. [Figure 11] 13 is a table showing an example of the speed of a developing unit according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram illustrating an image forming apparatus 1. As shown in FIG. The image forming apparatus 1 according to this embodiment includes a paper feed unit 1A, a printing unit 1B, and a paper discharge unit 1C. The paper feed unit 1A includes a first paper storage section 11 to a fourth paper storage section 14 for storing paper P as an example of a recording medium. The paper feed unit 1A also has feed rolls 15-18 that correspond to the first paper storage section 11 to the fourth paper storage section 14, respectively, and feed the paper P stored in each paper storage section to a transport path connected to the printing unit 1B.

[0009] The printing unit 1B includes an image forming section 20 that forms an image on a sheet P. The printing unit 1B also includes a control section 21 that controls each section of the image forming apparatus 1. The printing unit 1B also includes an image processing section 22. The image processing section 22 performs image processing on image data transmitted from the image reading device 4 and the personal computer (PC) 5. The printing unit 1B is also provided with a UI (User Interface) 23, which is configured with a touch panel or the like and notifies the user of information and receives information input from the user.

[0010] Image forming section 20, as an example of an image forming means, is provided with six image forming units 30T, 30P, 30Y, 30M, 30C, and 30K (hereinafter, sometimes simply referred to as "image forming units 30") arranged in parallel at regular intervals. Each image forming unit 30 includes a photosensitive drum 31 on which an electrostatic latent image is formed while rotating in the direction of arrow A, a charging roll 32 which charges the surface of the photosensitive drum 31, a developing device 33 which develops the electrostatic latent image formed on the photosensitive drum 31, and a drum cleaner 34 which removes toner and the like from the surface of the photosensitive drum 31.

[0011] The image forming section 20 is also provided with a laser exposure device 26 that exposes the photoconductor drum 31 of each image forming unit 30 to laser light. The exposure of the photoconductor drum 31 by the laser exposure device 26 is not limited to using laser light. For example, a light source such as an LED (Light Emitting Diode) may be provided for each image forming unit 30, and the photoconductor drum 31 may be exposed using light emitted from the light source.

[0012] Each image forming unit 30 is configured similarly, except for the toner contained in the developer 33. The image forming units 30Y, 30M, 30C, and 30K form toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. Further, the image forming units 30T and 30P form toner images using toner corresponding to a corporate color, foaming toner for Braille, fluorescent color toner, toner for improving gloss, etc. In other words, the image forming units 30T and 30P form toner images using toner of a special color.

[0013] The image forming section 20 is also provided with an intermediate transfer belt 41 onto which the toner images of each color formed on the photosensitive drums 31 of the image forming units 30 are transferred. The image forming section 20 is also provided with a primary transfer roll 42 that transfers the respective color toner images of the respective image forming units 30 onto the intermediate transfer belt 41 at a primary transfer portion T1. The image forming unit 20 is also provided with a secondary transfer roll 40 that transfers the toner image transferred onto the intermediate transfer belt 41 onto the paper P at a secondary transfer portion T2. Furthermore, the image forming section 20 is provided with a belt cleaner 45 that removes toner and the like from the surface of the intermediate transfer belt 41, and a fixing device 80 that fixes the secondarily transferred image onto the paper P. The developing device 33 is an example of a developing unit, the intermediate transfer belt 41 is an example of a transfer unit, and the fixing device 80 is an example of a fixing unit.

[0014] The image forming unit 20 performs an image forming operation based on a control signal from the control unit 21 . Specifically, in the image forming unit 20, first, image processing is performed on the image data input from the image reading device 4 or the PC 5 by the image processing unit 22, and the image data after image processing is supplied to the laser exposure device 26. Then, for example, in a magenta (M) image forming unit 30M, the surface of the photosensitive drum 31 is charged by the charging roll 32, and then the laser exposure device 26 irradiates the photosensitive drum 31 with laser light modulated by image data obtained from the image processing unit 22.

[0015] As a result, an electrostatic latent image is formed on the photoconductor drum 31 . The formed electrostatic latent image is developed by the developing unit 33, and a magenta toner image is formed on the photosensitive drum 31. Similarly, yellow, cyan and black toner images are formed in the image forming units 30Y, 30C and 30K, and special color toner images are formed in the image forming units 30T and 30P.

[0016] The respective color toner images formed in each image forming unit 30 are electrostatically transferred sequentially by a primary transfer roll 42 onto an intermediate transfer belt 41 rotating in the direction of arrow C in Figure 1, and superimposed toner images are formed on the intermediate transfer belt 41. The superimposed toner image formed on the intermediate transfer belt 41 is transported to a secondary transfer portion T2 constituted by a secondary transfer roll 40 and a backup roll 49 as the intermediate transfer belt 41 moves.

[0017] On the other hand, the paper P is taken out from the first paper storage unit 11 by, for example, the delivery roll 15, and then transported to the position of the registration roll 74 via the transport path. When the superimposed toner image is transported to the secondary transfer portion T2, a sheet of paper P is supplied from the registration roll 74 to the secondary transfer portion T2 in accordance with the transport timing. Then, in the secondary transfer portion T2, the superimposed toner images are electrostatically transferred onto the paper P all at once by the action of a transfer electric field formed between the secondary transfer roll 40 and the backup roll 49.

[0018] Thereafter, the paper P onto which the superimposed toner images have been electrostatically transferred is transported to a fixing device 80. In the fixing device 80, pressure and heat are applied to the paper P on which the unfixed toner image has been formed, and the toner image is fixed to the paper P. Then, the sheet P on which the fixing process has been performed passes through a curl correction section 81 provided in the sheet discharge unit 1C, and is then conveyed to a sheet stacking section (not shown).

[0019] FIG. 2 is a diagram for explaining the developing unit 33 of the image forming apparatus 1, and is a schematic front view of the developing unit 33 as viewed from the same direction as that shown in FIG. 2, the developing unit 33 includes a container 331 that contains a developer (not shown). The container 331 is made of a resin container 332. The developer is a so-called two-component developer, which is made of a magnetic carrier and a colored toner. It is also possible to use a one-component developer. The housing 332 of the developing device 33 is arranged to extend along a direction perpendicular to the paper surface of FIG. 2, which is the direction from the front side to the rear side of the image forming apparatus 1 (see FIG. 1), and has a front side member (not shown) on the front side and a rear side member (not shown) on the rear side.

[0020] An opening 333 is provided in the housing 332 at a location facing the photoconductor drum 31 (see FIG. 1). A developing roll 334 that adheres a developer to the surface of the photoconductor drum 31 is provided in this opening 333. The developing roll 334 holds the developer to be supplied to the photoconductor drum 31. The position where the developer from the developing roll 334 is supplied to the photoconductor drum 31 is sometimes referred to as the developing position. The developing roll 334 is formed in a cylindrical shape and is arranged so as to extend along a direction from the front side to the rear side of the image forming apparatus 1. In addition, the developing roll 334 is arranged so as to extend along the longitudinal direction of the developing unit 33.

[0021] The developing roll 334 is provided with a developing sleeve 334G formed of a cylindrical body and rotated, and a magnet roll 334H disposed inside the developing sleeve 334G. The developing sleeve 334G is made of, for example, a metal such as SUS, etc. The developing sleeve 334G rotates in the direction of the arrow D in the figure.

[0022] Furthermore, in this embodiment, at the primary transfer portion T1 (see FIG. 1) between the developing roll 334 and the photosensitive drum 31, the developing sleeve 334G and the photosensitive drum 31 rotate so that they move in the same direction. The developing unit 33 is provided with a layer regulating member 335 that regulates the layer thickness of the developer held on the developing roll 334 .

[0023] 2, the developing device 33 is provided with a first transport section 337 and a second transport section 338 for transporting the developer. Hereinafter, the first transport section 337 and the second transport section 338 may be referred to as transport sections 337-338.

[0024] The transport sections 337 and 338 are provided on the opposite side of the developing roll 334 to the side on which the photosensitive drum 31 (see FIG. 1) is installed. Each of the transport sections 337-338 includes a rotating member 52, 53 extending along the rotation axis of the developing sleeve 334G that is driven to rotate, and rotates around the rotating member 52-53. That is, the transport sections 337-338 are disposed approximately parallel to the photosensitive drum 31 (see FIG. 1). The rotating member 52 is a so-called Admix auger that agitates the developer, and the rotating member 53 is a so-called Supply auger that supplies the developer to the developing roll 334.

[0025] Next, the rotation speeds of the developing rolls 334 and the rotating members 52-53 of each developing device 33 will be described in the cases where a special color toner image is formed and where it is not formed by the image forming unit 30. The rotation speeds of the rotating members 52-53 are sometimes referred to as the speeds of the transport sections 337-338. A first embodiment and a second embodiment will be described below.

[0026] <First embodiment> First, the first embodiment will be described. FIG. 3 is a diagram for explaining developing units 33A and 33B of the image forming apparatus 1 according to the first embodiment, where (a) shows the developing unit 33A and (b) shows another developing unit 33B. Although the developing units 33A and 33B have the same basic configuration, for convenience of explanation, the components of the developing unit 33A and the developing unit 33B to which they belong are indicated by reference numerals. That is, the components of the developing unit 33A are indicated by the suffix "A", and the components of the developing unit 33B are indicated by the suffix "B". Also, in FIG. 3, the components described in FIG. 2 may not be shown or described.

[0027] The developing device 33A shown in Fig. 3(a) is provided for the image forming units 30Y, 30M, 30C, 30K among the image forming units 30Y, 30M, 30C, 30K, 30P, 30T (see Fig. 1) described above, and forms yellow, magenta, cyan, and black toner images. The developing device 33B shown in Fig. 3(b) is provided for the image forming units 30P and 30T, and forms a toner image of a specific color.

[0028] More specifically, in the developing unit 33A, the developing sleeve 334G of the developing roll 334A and the rotating members 52A and 53A of the transport sections 337A and 338A are rotated by a drive source 61, as shown in FIG. Also, as shown in FIG. 3(b), in the developing device 33B, the developing sleeve 334G of the developing roll 334B is rotationally driven by a driving source 61, while the rotating members 52B and 53B of the conveying sections 337B and 338B are rotationally driven by a driving source 62 separate from the driving source 61.

[0029] Therefore, the developing roll 334A of the developing unit 33A and the rotating members 52A-53A of the transport sections 337A-338A and the developing roll 334B of the developing unit 33B rotate at different speeds but at a predetermined ratio. Also, the rotating members 52B-53B of the transport sections 337B-338B of the developing unit 33B can rotate at a ratio different from that of the rotating members 52A-53A of the transport sections 337A-338A of the developing unit 33A.

[0030] Here, the driving source 61 shown in Fig. 3(b) drives the developing roll 334B and is an example of a driving source that rotates the second developer holder. The driving source 62 shown in Fig. 3(b) drives the rotating members 52B-53B of the transport sections 337B-338B and is an example of another driving source that drives the second rotating members. In the first embodiment, developing unit 33B is configured to include two drive sources 61 and 62, but drive source 62 for driving rotating members 52B-53B may be omitted, and rotating members 52B-53B may be driven by drive source 61. In other words, a configuration may be adopted in which drive source 61 drives rotating members 52B-53B by changing the speed using, for example, a reduction gear.

[0031] 4 is a diagram showing an example of the hardware configuration of the control unit 21 of the image forming apparatus 1. The control unit 21 provided in the image forming apparatus 1 is realized by a computer. The control unit 21 includes an arithmetic processing unit 21a that executes digital arithmetic processing according to a program, and a secondary storage unit 21g that stores information. The secondary storage unit 21g is realized by an existing information storage device such as an HDD (Hard Disk Drive), a semiconductor memory, or a magnetic tape.

[0032] The arithmetic processing unit 21a is provided with a CPU 21b as an example of a processor. The arithmetic processing unit 21a is also provided with a RAM 21c used as a working memory for the CPU 21b, and a ROM 21d in which programs executed by the CPU 21b are stored. The arithmetic processing unit 21a is also provided with a non-volatile memory 21e that is rewritable and can retain data even if the power supply is interrupted, and an interface unit 21f that controls each unit, such as a communication unit, connected to the arithmetic processing unit 21a.

[0033] The non-volatile memory 21e is composed of, for example, a battery-backed SRAM, a flash memory, etc. The secondary storage unit 21g stores files and the like, as well as programs executed by the arithmetic processing unit 21a. In this embodiment, the arithmetic processing unit 21a reads programs stored in the ROM 21d or the secondary storage unit 21g, thereby executing each process.

[0034] The program executed by the CPU 21b may be provided to the image forming apparatus 1 in a state where it is stored in a computer-readable recording medium such as a magnetic recording medium (such as a magnetic tape or a magnetic disk), an optical recording medium (such as an optical disk), a magneto-optical recording medium, or a semiconductor memory. The program executed by the CPU 21b may also be provided to the image forming apparatus 1 using a communication means such as the Internet.

[0035] In this specification, the term "processor" refers to a processor in a broad sense, including general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.). In addition, the operations of the processor may not only be performed by one processor, but may be performed by multiple processors in physically separate locations working together. The order of the operations of the processor is not limited to the order described in this embodiment, and may be changed.

[0036] FIG. 5 is a block diagram illustrating the functional configuration of the control unit 21 according to the first embodiment. 5, the control unit 21 includes a spot color printing judgment unit 91, a speed determination unit 92, and drive source control units 93 and 94. The spot color printing judgment unit 91 and the like are realized by the CPU 21b (see FIG. 4). In addition, the driving sources 61 and 62 located outside the control unit 21 in FIG. 5 are the driving sources 61 and 62 in FIGS.

[0037] The spot color printing judgment unit 91 judges whether or not the print job accepted by the image forming apparatus 1 is for forming a spot color toner image. That is, the spot color printing judgment unit 91 judges, based on the print job, whether to form only yellow (Y), magenta (M), cyan (C), and black (K) toner images and not to form a spot color toner image, or to form yellow (Y), magenta (M), cyan (C), and black (K) toner images and a spot color toner image.

[0038] The speed determination unit 92 determines the speed of the rotating members 52B-53B of the transport units 337B-338B in the developing unit 33B depending on whether spot color printing is performed using spot color toner. The speed is a speed corresponding to the upper limit of output pages per minute (ppm), that is, the process speed, but is not limited to this and may be a specific rotation speed of the rotating members 52B-53B.

[0039] More specifically, in an example in which information indicating a predetermined speed for spot color printing is stored in, for example, ROM 21d (see FIG. 4), when the result of the judgment by the spot color printing judgment unit 91 is spot color printing, the speed determination unit 92 reads out the information indicating the speed from ROM 21d as the speed to be determined.

[0040] It should be noted that the speed of the transport sections 337B to 338B when not performing spot color printing is a normal speed that is determined in advance and is not determined by the speed determination section 92. However, the present invention is not limited to this and a mode in which the speed is determined by the speed determination section 92 is also possible.

[0041] In addition, the speed of the developing roll 334A and the transport parts 337A-338A of the developing unit 33A and the speed of the developing roll 334B of the developing unit 33B are the same predetermined speeds whether or not spot color printing is being performed, and are not dependent on the speed determination unit 92, but are not limited to this. In other words, if the speeds of the developing rolls 334A, 334B and the transport parts 337A-338A differ depending on whether spot color printing is being performed, a mode in which the speed determination unit 92 determines such speeds depending on whether spot color printing is being performed or not is also conceivable.

[0042] The drive source control unit 93 controls the drive source 61. That is, the drive source control unit 93 controls the drive source 61 so that the developing rolls 334A and 334B and the transport units 337A to 338A move at predetermined speeds.

[0043] The drive source control unit 94 controls the drive source 62. That is, the drive source control unit 94 controls the drive source 62 so that the transport units 337B to 338B move at the speed determined by the speed determination unit 92.

[0044] FIG. 6 is a flowchart showing an example of a processing procedure for speed control of the transport sections 337B to 338B of the developing device 33B when a print job is accepted in the first embodiment. In the example shown in FIG. 6, when the image forming apparatus 1 receives a print job (step 101), the spot color printing determination unit 91 (see FIG. 4) determines whether the print job is spot color printing that uses spot color toner (step 102).

[0045] If the accepted print job is spot color printing (Yes in step 102), the speed determination unit 92 (see FIG. 4) determines the speed of the transport units 337B to 338B (see FIG. 3(b)) of the developing unit 33B (step 103).

[0046] After the determination, the image forming unit 20 (see FIG. 1) starts to operate, and the developing rolls 334A, 334B and the transport units 337A-338A, 337B-338B start to rotate. At this time, the drive source control unit 94 controls the driving of the drive source 62 so that the speed of the transport units 337B-338B becomes the determined speed (step 104). The speed of the transport units 337B-338B is not changed until the print job is completed. In other words, the speed of the transport units 337B-338B is not changed from the start to the stop of the rotation of the developing rolls 334A, 334B.

[0047] If the print job is not spot color printing (No in step 102), the drive source control unit 94 controls the drive of the drive source 62 so that the transport units 337B to 338B of the developing unit 33B move at a predetermined speed (step 104).

[0048] FIG. 7 is a table showing an example of the rotation speeds and transport speeds in the developing units 33A and 33B according to the first embodiment. In the table shown in FIG. 7, the rotation speeds and transport speeds of the developing devices 33A and 33B are shown for the cases of YMCK and K, and for each case for spot color printing and other printing. In addition, the rotational speed of the developing roll 334A in the developing device 33A is synonymous with the rotational speed of the photosensitive drum 31 to which the developer is supplied from the developing roll 334A, and the rotational speed of the developing roll 334B in the developing device 33B is synonymous with the rotational speed of the photosensitive drum 31 to which the developer is supplied from the developing roll 334B. The transport speed of transport sections 337A-338A in developing device 33A is synonymous with the rotation speed of rotating members 52A-53A, and the transport speed of transport sections 337B-338B in developing device 33B is synonymous with the rotation speed of rotating members 52B-53B.

[0049] As shown in Fig. 7, the rotation speed is divided into "high speed" and "low speed", and the conveying speed is divided into "high speed" and "low speed". The "high speed" and "low speed" of the rotation speed here indicate the degree of speed, and similarly, the "high speed" and "low speed" of the conveying speed indicate the degree of speed. As an example of the rotation speed, if the "high speed" is 85 ppm, which is the upper limit of the output number of 85 sheets per minute, the "low speed" is, for example, 40 ppm. Note that the "high" rotation speed and the "high" conveying speed may be the same or different. Similarly, the "low" rotation speed and the "high" conveying speed may be the same or different.

[0050] When printing YMCK colors other than spot colors, the rotation speed of developing roll 334A of developing unit 33A and the transport speed of transport sections 337A-338A, and the rotation speed of developing roll 334B of developing unit 33B and the transport speed of transport sections 337B-338B are all high.

[0051] On the other hand, in the case of a special color toner, for example, a gold toner or a silver toner containing aluminum pieces, or a white toner that requires a large amount of developer, the fixing temperature needs to be high to meet gloss and the like. For this reason, in the case of YMCK colors and special colors, the speeds of the developing rolls 334A, 334B and the transport sections 337A-338A are slow to ensure a high fixing temperature, whereas the speed of the transport sections 337B-338B is high. In other words, in the image forming units 30T, 30P having the developer 33B, when spot color printing is performed, even if the photoconductor drum 31 (see FIG. 1) and the developing roll 334B (see FIG. 3(b)) are slowed down compared to when spot color printing is not performed, the rotating members 52B-53B of the transport sections 337B-338B do not slow down. This prevents the charge amount of the developer containing the special color toner stirred and transported by the transport sections 337B-338B of the developing device 33B from decreasing as the transport speed of the transport sections 337B-338B decreases. In other words, even if the rotation speed of the developing roll 334A and the rotation speed of the developing roll 334B decrease when printing in a spot color, the decrease in the charge amount of the spot color developer is suppressed by making the decrease in the transport speed of the transport sections 337B to 338B that transport the spot color developer smaller than the decrease in the rotation speed of the developing roll 334B.

[0052] In addition, in the case of K color, when spot color printing is not performed, the rotation speed of the developing rolls 334A, 334B and the transport speed of the transport sections 337A-338A, 337B-338B are high, as in the case of YMCK colors. In addition, when spot color printing is performed, the rotation speed of the developing rolls 334A, 334B and the transport speed of the transport sections 337A-338A are low, while the transport speed of the transport sections 337B-338B is high, as in the case of YMCK colors.

[0053] In FIG. 7, focusing on spot color printing, the speed of the rotating members 52B to 53B when the developing roll 334B rotates at a low speed is high, which is higher than the low speed which is the speed of the rotating members 52A to 53A when the developing roll 334A rotates at a low speed.

[0054] 7, when focusing on printing that is not a special color, the rotating members 52B-53B rotate at high speed when the developing roll 334B rotates at high speed. That is, the high speed at which the rotating members 52B-53B rotate when the developing roll 334B rotates at high speed for printing that is not a special color is the same as the speed of the rotating members 52B-53B when the developing roll 334B rotates at low speed for printing that is a special color.

[0055] 3, the developing roll 334A of the developing unit 33A is an example of a rotating first developer holder, and the developing roll 334B of the developing unit 33B is an example of a rotating second developer holder. The transport sections 337A-338A of the developing unit 33A are an example of a first transport means, and the transport sections 337B-338B of the developing unit 33B are an example of a second transport means. The YMCK color developers are an example of a first developer of one color, and the special color developer is an example of a second developer of another color. Furthermore, the driving source 61 is an example of a driving source that rotates the second developer carrier, and the driving source 62 is an example of another driving source. 7, the "high" rotation speed is an example of a first rotation speed, and the "low" rotation speed is an example of a second rotation speed. Also, the "high" transport speed in the figure is an example of a first transport speed, and the "low" transport speed is an example of a second transport speed.

[0056] <Second embodiment> Next, a second embodiment will be described. In the second embodiment, the configurations of the image forming units 30Y, 30M, 30C, and 30K are the same as those in the first embodiment (see FIG. 3(a)), while the configurations of the image forming units 30T and 30P are different from those in the first embodiment (see FIG. 3(b)). A specific description will be given below. In the second embodiment, since there are configurations and controls common to the first embodiment, the description thereof may be omitted.

[0057] 8A and 8B are diagrams illustrating developing units 33C and 33D of an image forming apparatus 1 according to a second embodiment, where (a) illustrates developing unit 33C and (b) illustrates another developing unit 33D. Fig. 8 corresponds to Fig. 3 illustrating the first embodiment. In the second embodiment, the developing device 33A (see FIG. 3(a)) described in the first embodiment is provided, but instead of the developing device 33B described in the first embodiment, developing devices 33C and 33D are provided. That is, in the second embodiment, developing devices 33A, 33C, and 33D are provided. Although the developing units 33C and 33D have the same basic configuration as the developing unit 33B (see FIG. 3(b)), for ease of explanation, the components are indicated by reference numerals to indicate whether they belong to the developing unit 33C or the developing unit 33D. That is, the components of the developing unit 33C are indicated by a suffix "C" and the components of the developing unit 33D are indicated by a suffix "D."

[0058] The developing device 33C shown in Fig. 8(a) is provided in the image forming unit 30P and forms a toner image of a special color. The developing device 33D shown in Fig. 8(b) is provided in the image forming unit 30T and forms a toner image of a special color.

[0059] To explain further, as shown in FIG. 8(a), in the developing unit 33C, the developing sleeve 334G of the developing roll 334C is rotationally driven by a driving source 61, while the rotating members 52C, 53C of the conveying sections 337C, 338C are rotationally driven by a driving source 63 separate from the driving source 61. Also, as shown in FIG. 8(b), in the developing device 33D, the developing sleeve 334G of the developing roll 334D is rotationally driven by a driving source 61, while the rotating members 52D, 53D of the conveying sections 337D, 338D are rotationally driven by a driving source 64 separate from the driving source 61.

[0060] Therefore, the developing roll 334C of the developing unit 33C and the developing roll 334D of the developing unit 33D rotate at the same speed, which is the same as the speed of the developing roll 334A of the developing unit 33A and the rotating members 52A to 53A of the transport sections 337A to 338A (see FIG. 3(a)).

[0061] Furthermore, the rotating members 52C-53C of the transport sections 337C-338C of the developing unit 33C are capable of rotating at a speed different from that of the rotating members 52A-53A of the developing unit 33A (see FIG. 3(a)). Rotating members 52D-53D of transport sections 337D-338D of developing unit 33D can rotate at a different speed from rotating members 52A-53A of developing unit 33A (see FIG. 3(a)), and can rotate at a different speed from rotating members 52C-53C of developing unit 33C.

[0062] Here, the driving source 63 shown in Fig. 8(a) drives the rotating members 52C-53C of the transport sections 337C-338C and is an example of another driving source that drives the second rotating members. Also, the driving source 64 shown in Fig. 8(b) drives the rotating members 52D-53D of the transport sections 337D-338D and is an example of another driving source that drives the second rotating members.

[0063] FIG. 9 is a block diagram illustrating the functional configuration of a control unit 21 according to the second embodiment, and corresponds to FIG. 5 illustrating the first embodiment, and descriptions of configurations common to FIG. 5 may be omitted.

[0064] In the example shown in FIG. 9, the control unit 21 includes a spot color printing judgment unit 91 , a spot color toner information storage unit 95 , a speed determination unit 92 , and drive source control units 93 , 96 , and 97 . In addition, the driving sources 63, 64 located outside the control unit 21 in FIG. 9 are the driving sources 63, 64 in FIGS. 8(a) and 8(b) described above.

[0065] The special color toner information storage section 95 stores special color toner information which is information indicating the special color toner contained in the developing devices 33C and 33D of the image forming units 30P and 30T. The spot color toner information is information necessary for determining the speed by the speed determination unit 92. More specifically, the spot color toner information is information for identifying the type of toner of each of the spot color toners of the developing devices 33C and 33D, such as gold toner, silver toner, white toner, etc. By using the spot color toner information, the speed of each of the rotating members 52C to 53C and 52D to 53D is determined according to the toner.

[0066] The special color toner information may include information indicating the physical property values ​​of the toner components instead of or in addition to the specific toner name. Such information indicating the physical property values ​​is an example of information indicating the ease of charging. Note that, instead of the information indicating the physical property values, measured values ​​obtained by a measurement performed in advance may be used. The special color toner information referred to here may be information stored in a storage medium (not shown) included in the developing devices 33C and 33D of the image forming units 30P and 30T.

[0067] The drive source control unit 96 controls the drive source 63. That is, the drive source control unit 96 controls the drive source 63 so that the transport units 337C to 338C move at a predetermined speed.

[0068] The drive source control unit 97 controls the drive source 64. That is, the drive source control unit 97 controls the drive source 64 so that the transport units 337D to 338D move at a predetermined speed.

[0069] 9, developing roll 334C of developing unit 33C and developing roll 334D of developing unit 33D are an example of a rotating second developer holder. Transport sections 337C-338C of developing unit 33C and transport sections 337D-338D of developing unit 33D are an example of a second transport means. Drive sources 63 and 64 are an example of another drive source. In Fig. 11, "V11" is an example of a first rotation speed, and "V13" is an example of a second rotation speed. Also, in the same figure, "V21" is an example of a first transport speed, and "V23" is an example of a second transport speed. Furthermore, in the same figure, "V22" is an example of a transport speed of the second developer that is smaller than the first transport speed, and "V20" is an example of a transport speed of the second developer that is larger than the first transport speed.

[0070] Fig. 10 is a flowchart showing an example of a speed control process for conveyance sections 337C-338C of developing unit 33C and conveyance sections 337D-338D of developing unit 33D when a print job is accepted in the second embodiment. Fig. 10 corresponds to Fig. 6 which explains the first embodiment, and explanations of configurations common to Fig. 6 may be omitted.

[0071] In the example shown in FIG. 10, the spot color printing determination unit 91 (see FIG. 9) determines whether the accepted print job is spot color printing using spot color toner (steps 201, 202). If it is determined that the printing is spot color printing (Yes in step 202), the spot color toner information stored in the spot color toner information storage unit 95 is read out as information about the spot color toner used in the spot color printing (step 203).

[0072] Based on the read out spot color toner information, the speed determination unit 92 (see FIG. 9) determines the speeds of the transport sections 337C-338C (see FIG. 8(a)) of the developing unit 33C and the transport sections 337D-338D (see FIG. 8(b)) of the developing unit 33D (step 204). After that, the drive source control units 96, 97 control the drive sources 63, 64 so that the transport sections 337C-338C and the transport sections 337D-338D reach the determined speeds (step 205).

[0073] If the print job is not spot color printing (No in step 202), drive source control units 96, 97 control the drive sources 63, 64 so that transport units 337C-338C and transport units 337D-338D move at predetermined speeds (step 205).

[0074] FIG. 11 is a table showing an example of the speeds in the developing units 33A, 33C, and 33D according to the second embodiment, and corresponds to FIG. 7 which explains the first embodiment. In FIG. 11, unlike FIG. 7 which shows the rotation speed and the transport speed as "high speed" and "low speed", the rotation speeds are shown as V11 and V13, and the transport speeds are shown as V20, V21, V22, and V23. The magnitude relationships are V11>V13, V20>V21>V22>V23. For example, V20 corresponds to 85 ppm, V11 and V21 correspond to 80 ppm, V22 corresponds to 75 ppm, and V13 and V23 correspond to 40 ppm.

[0075] The special color P shown in FIG. 11 is due to the special color toner contained in the developing device 33C, and the special color T is due to the special color toner contained in the developing device 33D. The table shown in FIG. 11 shows the speeds of the developers 33A, 33C, and 33D for the colors YMCK when spot color printing including spot colors P and T is performed and when it is not performed.

[0076] Specifically, when printing in YMCK colors and not in spot colors, the rotational speeds of developing roll 334A of developing unit 33A, developing roll 334C of developing unit 33C, and developing roll 334D of developing unit 33D are all speed V11, and the transport speeds of transport sections 337A-338A of developing unit 33A, transport sections 337C-338C of developing unit 33C, and transport sections 337D-338D of developing unit 33D are all speed V21.

[0077] On the other hand, in the case of YMCK colors and spot colors P and T, the rotational speed of the developing rolls 334A, 334C, and 334D is speed V13 which is slower than speed V11 (V11>V13), and the transport speed of the transport sections 337A to 338A is speed V23 which is slower than speed V21 (V21>V23). In contrast, the conveying speed of conveying sections 337C to 338C is speed V20, which is faster than conveying speed V21 (V20>V21), and the conveying speed of conveying sections 337D to 338D is speed V22, which is slower than speed V21 and faster than speed V23 (V21>V22>V23). In this way, the conveying speed V20 of conveying sections 337C to 338C and the conveying speed V22 of conveying sections 337D to 338D are determined based on speed V21.

[0078] In this way, in the second embodiment, the transport speed of transport sections 337C-338C of developing device 33C is different from the transport speed of transport sections 337D-338D of developing device 33D. That is, by changing the speed at which the special color toner is stirred depending on the type of the special color toner, the charge amount of the special color toner of developing device 33C and the charge amount of the special color toner of developing device 33D are ensured.

[0079] Note that while Figure 11 shows the case of YMCK colors and spot colors P and T, this is not limited to this, and it is possible to use a similar speed in other cases, i.e., the case of YMCK colors and spot color P, or the case of YMCK colors and spot color T.

[0080] <Additional Notes> (((1))) An image forming apparatus capable of performing a first operation of forming an image by a first developer of one color transported by a first transport means and held by a rotating first developer holder, and a second operation of forming an image by a second developer of another color transported by a second transport means and held by a rotating second developer holder, In the first operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a first rotation speed; a transport speed of the first developer by the first transport means and a transport speed of the second developer by the second transport means are a first transport speed; In the second operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a second rotation speed that is lower than the first rotation speed; a transport speed of the first developer by the first transport means is a second transport speed that is lower than the first transport speed, and a transport speed of the second developer by the second transport means is a transport speed that is higher than the second transport speed; Image forming device. (((2))) the second developer is transported by the second transport means by a drive source different from a drive source that rotates the second developer carrier; 4. The image forming apparatus according to claim 1, wherein the first and second electrodes are arranged in a first direction. (((3))) a transport speed of the second developer by the second transport means in the second operation is determined based on the first transport speed; 2. The image forming apparatus according to claim 1 , wherein the first and second electrodes are arranged in a first direction and a second direction. (((4))) a transport speed of the second developer by the second transport means in the second operation is equal to the first transport speed; The image forming apparatus according to (((3))) is characterized in that (((5))) a transport speed of the second developer by the second transport means in the second operation is lower than the first transport speed; The image forming apparatus according to (((3))) is characterized in that (((6))) a transport speed of the second developer by the second transport means in the second operation is higher than the first transport speed; The image forming apparatus according to (((3))) is characterized in that (((7))) a conveying speed of the first conveying means and a conveying speed of the second conveying means are not changed during a period from when the first developer carrier and the second developer carrier start to when they stop rotating; 4. The image forming apparatus according to claim 3, wherein the image forming apparatus comprises: (((8))) a transport speed of the second developer by the second transport means in the second operation is determined depending on the second developer; 2. The image forming apparatus according to claim 1 , wherein the first and second electrodes are arranged in a first direction and a second direction. (((9))) a transport speed of the second developer by the second transport means in the second operation is determined according to information indicating the ease of charging the second developer; The image forming apparatus according to (((8))) is characterized in that (((10))) a processor for controlling an image forming apparatus capable of performing a first operation of forming an image with a first developer of one color carried by a first carrying means and held by a rotating first developer carrier, and a second operation of forming an image with a second developer of another color carried by a second carrying means and held by a rotating second developer carrier, In the first operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a first rotation speed; a function of controlling a transport speed of the first developer by the first transport means and a transport speed of the second developer by the second transport means to be a first transport speed; In the second operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a second rotation speed that is lower than the first rotation speed; a function of controlling a transport speed of the first developer by the first transport means to be a second transport speed lower than the first transport speed, and a function of controlling a transport speed of the second developer by the second transport means to be a transport speed higher than the second transport speed; A program to achieve this.

[0081] According to the invention (((1))), when the rotational speed of the first developer holder and the rotational speed of the second developer holder are slower in the second operation than in the first operation, the decrease in the charge amount of the second developer can be suppressed compared to when the transport speed of the second transport means that transports the second developer is slower than in the first operation. According to the invention (((2))), the transport of the second developer by the second transport means can be simplified in configuration compared to a case in which the transport is not performed by a drive source separate from the drive source that rotates the second developer holder. According to the invention (((3))), the transport speed of the second developer by the second transport means in the second operation can be controlled more simply than in a case where the configuration is not provided in which the transport speed is determined based on the first transport speed. According to the invention (((4))), the transport speed of the second developer by the second transport means in the second operation can be simplified compared to a case in which the configuration is not provided such that the transport speed is the same as the first transport speed. According to the invention (((5))), the transport speed of the second developer by the second transport means in the second operation can ensure the charge amount of the second developer compared to a case in which the transport speed is not slower than the first transport speed. According to the invention (((6))), the transport speed of the second developer by the second transport means in the second operation can ensure the charge amount of the second developer compared to a case in which the transport speed is not faster than the first transport speed. According to the invention (((7))), the conveying speed of the first conveying means and the conveying speed of the second conveying means can prevent uneven distribution of the first developer in the first conveying means and the second developer in the second conveying means, compared to a case in which the conveying speed is not changed between the start and stop of rotation of the first developer holder and the second developer holder. According to the invention (((8))), the transport speed of the second developer by the second transport means in the second operation can ensure the charge amount of the second developer compared to a case in which the configuration is not determined according to the second developer. According to the invention (((9))), the transport speed of the second developer by the second transport means in the second operation can ensure the amount of charge of the second developer compared to a case in which the transport speed is not determined according to information indicating the ease of charging the second developer. According to the invention (((10))), when the rotational speed of the first developer holder and the rotational speed of the second developer holder are slower in the second operation than in the first operation, the decrease in the charge amount of the second developer can be suppressed compared to the case where the transport speed of the second transport means that transports the second developer is slower than in the first operation. [Explanation of symbols]

[0082] 1... image forming apparatus, 21b... CPU, 33, 33A, 33B, 33C, 33D... developing device, 61 to 64... driving source, 334A, 334B, 334C, 334D... developing roll, 337A to 338A, 337B to 338B, 337C to 338C, 337D to 338D... conveying section

Claims

1. An image forming apparatus capable of performing a first operation of forming an image by a first developer of one color transported by a first transport means and held by a rotating first developer holder, and a second operation of forming an image by a second developer of another color transported by a second transport means and held by a rotating second developer holder, In the first operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a first rotation speed, a transport speed of the first developer by the first transport means and a transport speed of the second developer by the second transport means are a first transport speed, In the second operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a second rotation speed that is lower than the first rotation speed; a transport speed of the first developer by the first transport means is a second transport speed which is lower than the first transport speed, and a transport speed of the second developer by the second transport means is a transport speed which is higher than the second transport speed; Image forming device.

2. the second developer is transported by the second transport means by a drive source different from a drive source that rotates the second developer carrier; 2. The image forming apparatus according to claim 1,

3. a transport speed of the second developer by the second transport means in the second operation is determined based on the first transport speed; 2. The image forming apparatus according to claim 1,

4. a transport speed of the second developer by the second transport means in the second operation is equal to the first transport speed; 4. The image forming apparatus according to claim 3.

5. a transport speed of the second developer by the second transport means in the second operation is lower than the first transport speed; 4. The image forming apparatus according to claim 3.

6. a transport speed of the second developer by the second transport means in the second operation is higher than the first transport speed; 4. The image forming apparatus according to claim 3.

7. a conveying speed of the first conveying means and a conveying speed of the second conveying means are not changed during a period from when the first developer carrier and the second developer carrier start to when they stop rotating; 4. The image forming apparatus according to claim 3.

8. a transport speed of the second developer by the second transport means in the second operation is determined depending on the second developer; 2. The image forming apparatus according to claim 1,

9. a transport speed of the second developer by the second transport means in the second operation is determined according to information indicating the ease of charging the second developer; 9. The image forming apparatus according to claim 8,

10. a processor for controlling an image forming apparatus capable of performing a first operation of forming an image with a first developer of one color conveyed by a first conveying means and held by a rotating first developer holder, and a second operation of forming an image with a second developer of another color conveyed by a second conveying means and held by a rotating second developer holder, In the first operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a first rotation speed; a function of controlling a transport speed of the first developer by the first transport means and a transport speed of the second developer by the second transport means to be a first transport speed; In the second operation, a rotation speed of the first developer carrier and a rotation speed of the second developer carrier are a second rotation speed that is lower than the first rotation speed; a function of controlling a transport speed of the first developer by the first transport means to be a second transport speed lower than the first transport speed, and a function of controlling a transport speed of the second developer by the second transport means to be a transport speed higher than the second transport speed; A program to achieve this.

Images