JP2004054062A - Image forming apparatus and image forming method - Google Patents

Abstract

In a job in which monochrome and color printing are mixed, the productivity is improved without increasing the printing operation time.
Kind Code: A1 An external apparatus acquires the total number of image forming transfer materials in one print job and the number of transfer materials sufficient for monochrome image formation in which only monochrome data exists (S601). A ratio γ of the number of monochrome image forming transfer materials to the total number of image forming transfer materials is determined (S602). The calculation result γ0 of the ratio of the number of monochrome image forming transfer materials to the total number of image forming transfer materials is compared with a predetermined value M0 (S603). If M0 <= γ0, the transfer material having a color image is compared. Then, the image forming operation is performed while switching the color image forming mode and the monochrome image forming mode for the transfer material of only the monochrome image during the job operation (S604). If M0> γ0, the image forming operation in the color image forming mode is performed on all the image forming transfer materials (S605).
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus and an image forming method, and more particularly, to an image forming apparatus and an image forming apparatus that form an image by transferring an image formed by an image forming unit including a plurality of image carriers to a transfer material. About the method.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with the spread of a color (multiple color) image forming apparatus using an electrophotographic method, a demand for high-speed color output has been increasing in addition to a demand for recording quality of a color image. In order to meet this demand, several proposals have been made for image forming methods. Among them, Y (yellow) toner, M (magenta) toner, C (cyan) toner, and Bk (black) are called tandem type. There is a color image forming system in which each image is formed by a toner on a drum-shaped image carrier, and is sequentially transferred by a transfer unit to a transfer material conveyed by a transfer conveyance belt, and finally fixed. (See, for example, JP-A-09-288396).
[0003]
In the tandem type color image forming apparatus, as shown in FIG. 1, a transfer material set in a transfer material cassette 150 at a lower portion of a main body device is taken out one by one by a feed roller 151 and formed by a feed roller pair 140. Fed to the department.
[0004]
In the image forming section, a transfer conveyance belt 11a for conveying the transfer material is stretched flat by a plurality of rotating rollers in a transfer material conveyance direction (from the bottom to the top in the figure). The transfer material is electrostatically attracted to the transfer / conveying belt 11a by the applied attracting roller 153. Further, four drum-shaped image carriers (hereinafter, referred to as photosensitive drums) 101C, 101Y, 101M, and 101Bk are linearly arranged facing the belt transport surface, and constitute an image forming unit. ing.
[0005]
In each of the photoconductor drums 101C, 101Y, 101M, and 101Bk, a charging member, a developing device, and a transfer member are arranged so as to sandwich the transfer surface of the transfer transfer belt 11a so as to sequentially surround the peripheral surface thereof.
[0006]
Then, the respective color toners of C (cyan), Y (yellow), M (magenta), and Bk (black) are accommodated in the housings of the respective developing devices from the upstream side (the lower side in FIG. 1) in the transfer material transport direction. Each color image is sequentially transferred to a transfer material conveyed by the transfer conveyance belt 11a, so that a color image is formed. The transfer material is conveyed to a fixing section 152 located on the upper side of the apparatus, where the image is fixed and discharged.
[0007]
In the above-described color image forming apparatus, the frequency of performing multi-color printing, that is, not always performing full-color printing, but performing black-only printing, that is, monochrome (single-color) printing, is quite high. To cope with such usage, a tandem-type color image forming apparatus capable of switching between full-color printing and monochrome printing has been proposed.
[0008]
Here, in the tandem type color image forming apparatus, a means for forming a monochrome image by separating a photosensitive drum and a developing roller for conveying toner as a developer as a means for switching between full color recording and monochrome recording will be described. .
[0009]
3A and 3B are diagrams showing the contact operation and the separation operation of the developing device. First, in FIG. 3A, the photosensitive drum 101 in the developing device and the toner serving as the developer are removed. Since the developing roller 103 to be supplied is in a contact state, the toner can be conveyed to the photosensitive drum exposed by the image writing laser beam to form an image. In FIG. 3B, image formation is not performed because the photosensitive drum in the developing device and the developing roller for supplying toner serving as a developer are separated from each other.
[0010]
FIGS. 4A to 4C are schematic views of a tandem type color image forming apparatus provided with a developing separation mechanism, and a developing device that transports a developer from the photosensitive drums 101C, 101Y, 101M, and 101Bk and the image writing device. The rollers 103C, 103Y, 103M, and 103Bk and the transport belt 11a are shown.
[0011]
First, as shown in FIG. 4A, when a color (multiple color) image is formed, the development is performed by transporting the developer from the photoconductor drums 101C, 101Y, 101M, and 101Bk for four colors and the image writing device. A color image can be formed by abutting the rollers 103C, 103Y, 103M, and 103Bk.
[0012]
On the other hand, as shown in FIG. 4B, when a monochrome (single color) image is formed, image formation is performed using only the Bk image writing device in order to reduce performance degradation of the image writing device. Therefore, as described above, the photosensitive drums 101C, 101Y, and 101M and the developing rollers 103C, 103Y, and 103M are separated by using the contact and separation operations of the image writing device, and only the photosensitive drum 101Bk and the developing roller 103Bk are separated. A color image can be formed.
[0013]
Further, FIG. 4C shows that the photosensitive drums 101C, 101Y, 101M, and 101Bk are all separated from the developing rollers 103C, 103Y, 103M, and 103Bk (hereinafter referred to as a home position). Except for the image forming state, the home position is maintained.
[0014]
[Problems to be solved by the invention]
However, as described above, in the configuration in which the operation of contacting or separating the photosensitive drum and the developing roller that transports the toner as the developer is performed at the time of monochrome and full color recording, respectively, in a job in which monochrome and full color are mixed. During the operation of, the contact and separation of the photosensitive drum and the developing roller are performed each time recording is performed on each transfer material, and it is necessary to stop the recording operation only for the time required for the contact or separation. There is a problem that extra time is required until the recording is completed, and the recording productivity is reduced.
[0015]
The present invention has been made in view of such a problem, and an object of the present invention is to improve productivity without increasing printing operation time in a job in which monochrome and color printing are mixed. An image forming apparatus and an image forming method are provided.
[0016]
[Means for Solving the Problems]
According to an aspect of the present invention, at least one or more image carriers that are driven to rotate and an electrostatic latent image formed on the image carriers are provided. Latent image means; developing means for forming a toner image by attaching toner to the image carrier via a developing roller for supplying a toner as a developer to the electrostatic latent image; and transferring the toner image to a transfer material. Transfer means for transferring the image to the image carrier, a developing means for separating or abutting the developing roller of the developing means and the image carrier, and a transfer material suction for sucking the recording paper carried on the transfer material onto a transport belt Means, conveying means for conveying the transfer material adsorbed by the transfer material adsorbing means in a predetermined direction, and fixing means for thermally fixing the toner transferred by the transfer means to the transfer material conveyed by the conveying means. Forming a toner image by using A first image forming unit for controlling the developing roller of the developing unit and the image carrier in a contact state to form an image in a multi-color image forming mode; and a developing unit in a single-color image forming mode. A second image forming means for controlling the developing roller and the image bearing member to be separated from each other to form an image, at the start of one print job, the total number of image forming transfer materials in the print job, and the multi-color image Acquiring means for acquiring the number of multi-color image forming transfer materials to be image-formed in the formation mode and the number of single-color image forming transfer materials to be image-formed in the single-color image forming mode; and A first calculating unit that calculates a ratio of the number of image forming transfer materials, and a second calculating unit that calculates a ratio of the single color image forming transfer material to the multicolor image forming transfer material. Characterized in that it.
[0017]
According to a second aspect of the present invention, in the first aspect, the calculation result of the ratio of the number of the single-color image forming transfer materials to the total number of the image forming transfer materials by the first calculating means is determined in advance. When the value is equal to or less than the predetermined value, the image forming on the transfer material in one print job is performed by the first image forming unit that forms an image in the multi-color image forming mode.
[0018]
According to a third aspect of the present invention, in the first aspect of the invention, the calculation result of the ratio of the number of the single-color image forming transfer materials to the total number of the image forming transfer materials by the first calculating means is determined in advance. If the predetermined value or more, the image formation on the transfer material in one print job is performed in the multi-color image formation mode according to the image formation mode designated for each transfer material. The first image forming means and the second image forming means for forming an image in the single-color image forming mode are switched to form an image.
[0019]
According to a fourth aspect of the present invention, in the first aspect of the present invention, the calculation result of the ratio of the number of the single-color image forming transfer materials to the number of the multi-color image forming transfer materials is calculated by the second calculating means. If the predetermined value is equal to or less than a predetermined value, all image formation on the transfer material in one print job is performed by the first image forming unit that forms an image in the multi-color image mode. Features.
[0020]
According to a fifth aspect of the present invention, in the first aspect of the present invention, the calculation result of the ratio of the number of the single-color image forming transfer materials to the number of the multi-color image forming transfer materials is calculated by the second calculating means. If the value is equal to or greater than a predetermined value, image formation on the transfer material in one print job is performed in the multi-color image formation mode according to the image formation mode designated for each transfer material. An image is formed by switching between the first image forming unit for forming and the second image forming unit for forming an image in the monochrome image forming mode.
[0021]
According to a sixth aspect of the present invention, in the first aspect of the invention, the predetermined value to be compared with the calculation result of the ratio of the number of single-color image forming transfer materials by the first and second calculating means is an external value. It can be set from.
[0022]
According to a seventh aspect of the present invention, in an image forming method for forming an image by transferring an image formed by an image forming unit including a plurality of image carriers to a transfer material, an image forming request from an external device is not required. When this occurs, first, an acquisition step of acquiring the total number of image forming transfer materials and the number of single color image forming transfer materials in one print job from the external device; and A calculating step of calculating the ratio of the number of sheets, a comparing step of comparing the calculation result γ0 of the ratio of the number of the monochrome image forming transfer materials with a predetermined value M0, and a comparison result obtained in the comparing step is M0 <= γ0. In this case, it is necessary to switch the multi-color image formation mode for a transfer material having a multi-color image and the single-color image formation mode for a transfer material having only a single color image during a job operation. A first image forming step of performing an image forming operation from the first image forming step and an image forming operation of performing a multi-color image forming mode on all the image forming and transferring materials when the comparison result in the comparing step is M0> γ0. 2 image forming steps.
[0023]
According to an eighth aspect of the present invention, in an image forming method for forming an image by transferring an image formed by an image forming unit including a plurality of image carriers to a transfer material, an image forming request from an external device is not required. When this occurs, first, an acquisition step of acquiring the number of multi-color image formation transfer materials and the number of single-color image formation transfer materials in one job from an external device, and the number of single-color image formation transfer materials with respect to the number of multi-color image formation transfer materials Calculating a ratio of the number of the multi-color image forming transfer materials to the number of the mono-color image forming transfer materials, and comparing the calculated result γ1 with a predetermined value M1. If the comparison result is M1 = <γ1, the multi-color image forming mode is set for the transfer material having the multi-color image, and the single-color image forming mode is set for the transfer material having only the single-color image. A first image forming step in which an image forming operation is performed while switching the forming mode during a job operation, and when the comparison result in the comparing step is M1> γ1, a multi-color image is formed on the entire image forming transfer material. A second image forming step of performing an image forming operation in a forming mode.
[0024]
According to a ninth aspect of the present invention, in an image forming method for forming an image by transferring an image formed by an image forming means including a plurality of image carriers to a transfer material, an image forming request from an external device is When this occurs, first, the number of multi-color image forming transfer materials and the number of mono-color image forming transfer materials in one job from an external device and the plurality of multi-color image forming operation or the single color image forming operation are determined. An obtaining step of obtaining a predetermined value M2 to be compared with a calculated value of the ratio of the number of the single-color image forming transfer materials to the number of the color image forming transfer materials; and A calculating step of calculating a ratio, and a comparing step of comparing a calculation result γ2 of a ratio of the number of the monochrome image forming transfer materials to the number of the plurality of image forming transfer materials with the predetermined value M2. When the comparison result in the comparison step is M2 = <γ2, the multi-color image forming mode is set for the transfer material having the multi-color image, the single-color image forming mode is set for the transfer material having only the single-color image, A first image forming step in which an image forming operation is performed while switching during a job operation, and if the comparison result in the comparing step is M2> γ2, the image in the multi-color image forming mode is applied to all the image forming transfer materials. And a second image forming step of performing a forming operation.
[0025]
According to a tenth aspect of the present invention, there is provided a program for causing a computer to execute the steps of the seventh, eighth, or ninth aspects.
[0026]
According to an eleventh aspect of the present invention, there is provided a computer-readable recording medium having recorded thereon a program for executing the steps of the seventh, eighth or ninth aspects.
[0027]
As described above, in the image forming apparatus of the present invention, when the ratio of the monochrome (single color) image forming mode in one print job is equal to or less than the predetermined value, the contact or separation operation between the photosensitive drum and the developing roller is performed. Since no contact or separation is required, an image forming apparatus with high productivity can be provided.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 are schematic side sectional views of an image forming apparatus according to the present invention. FIG. 1 is an explanatory diagram of a state in which color (multiple colors) printing is performed, and FIG. 2 is a state of performing monochrome (single color) printing. FIG.
[0029]
<Overall configuration>
The color image forming apparatus shown in FIG. 1 includes four photosensitive drums 101 (101C, 101Y, 101M, and 101Bk), and two middle photosensitive drums with respect to upper and lower photosensitive drums 101C and 101Bk. 101Y and 101M are arranged so as to protrude toward the transfer / conveying belt side by about 1 mm. The four photosensitive drums 101 are driven to rotate counterclockwise in the figure by a driving unit (not shown).
[0030]
A charging unit 104 (104C, 104Y, 104M, 104Bk) that uniformly charges the surface of the photosensitive drum 1 in order according to the rotation direction around each photosensitive drum, irradiates a laser beam based on image information, and sensitizes the photosensitive drum. An exposure unit 108 (108C, 108Y, 108M, 108Bk) for forming an electrostatic latent image on the body drum 101, and a developing unit 103 (103C, 103Y, 108B) for attaching toner to the electrostatic latent image and visualizing it as a toner image. 103M, 103Bk), a transfer section (transfer blade) 102 (102C, 102Y, 102M, 102Bk) for transferring the toner image on the photosensitive drum 101 to a transfer material, and the like, and constitute an image forming section.
[0031]
Here, the photosensitive drum 101, the charging unit 104, and the developing unit 103 are integrally formed as a cartridge to form the process cartridge 106 (106C, 106Y, 106M, 106Bk).
[0032]
Further, the transfer material fed from the feeding unit 150 is conveyed to the image forming unit by the conveying unit 11 constituted by a conveying belt, and the color images are sequentially transferred and the color images are recorded. The image is fixed to the sheet and is discharged to the discharge section 13 by the discharge roller pair.
[0033]
Hereinafter, the configuration of each unit will be sequentially described.
<Image forming configuration>
Each photoconductor drum 101 as an image carrier is formed by applying an organic photoconductor layer (OPC) to an outer peripheral surface of an aluminum cylinder having a diameter of 30 mm. The photosensitive drum 101 is rotatably supported at both ends by flanges, and is driven to rotate counterclockwise in the figure by transmitting a driving force from a drive motor (not shown) to one end. .
[0034]
Each charging unit 104 is a conductive roller formed in the shape of a roller. The roller is brought into contact with the surface of the photosensitive drum 101, and a charging bias voltage is applied by a power supply (not shown) to apply a charging bias voltage to the surface of the photosensitive drum 101. Is charged uniformly.
[0035]
The exposure unit 108 forms an electrostatic latent image on the photosensitive drum 101 by irradiating a laser beam based on image information by a drive circuit (not shown).
[0036]
The developing units 103 (103C, 103Y, 103M, and 103Bk) are adjacent to a toner storage unit that stores toner of each color of black, cyan, magenta, and yellow, and the surface of the photosensitive drum 101, and are rotationally driven by a driving unit (not shown). At the same time, development is performed by applying a developing bias voltage from a developing bias power supply (not shown). The toner storage section stores cyan, yellow, magenta, and black toners in order from the upstream side in the transport direction of the transfer material.
[0037]
In addition, transfer rollers 102C, 102Y, 102M, and 102Bk that are in contact with the transfer / transport belt 11 are provided in parallel with the four photosensitive drums 101C, 101Y, 101M, and 101Bk, respectively, inside the transfer / transport belt 11a. ing. The transfer roller 102 is connected to a transfer bias power supply (not shown), and a positive charge is applied to the transfer material from the transfer roller 102 via the transfer conveyance belt 11a. A negative toner image on the photosensitive drum 101 is sequentially transferred to the transfer material in contact, and a color image is formed.
[0038]
The heat and pressure are applied to the toner image transferred to the transfer material when the toner image passes through a fixing unit 152 including a heating roller that is driven to rotate and a pressure roller that is driven to rotate, so that the toner image is fixed.
[0039]
<Transfer material transport configuration>
After the transfer material is fed from the feeding unit, the transfer material is transported to the image forming area by the transport belt 11a. In the paper feeding unit, a plurality of transfer materials are stored in a paper feed cassette 150, and a half-moon-shaped pickup roller 151 that picks up the transfer materials one by one is rotatably provided near the paper feed cassette 150. Have been. Then, the transfer material picked up by the intermittent rotation of the pickup 151 is fed to the transfer / conveyance belt 11a by the feed roller pair 140.
[0040]
The transfer / conveyance belt 11a as a transfer material carrier constituting the conveyance unit is stretched and supported by four rollers of a drive roller 11b and driven rollers 11c, 11d and 11e, and all the photosensitive drums 101C, 101Y and 101M. , 101Bk. This transfer conveyance belt 11 is usually 10 ¹⁰ -10 ¹⁴ It is composed of an endless film-like member having a thickness of 100 to 150 μm and a volume resistivity of Ω · cm.
[0041]
Then, the transfer conveyance belt 11a is circulated by the drive roller 11b so that the transfer material is electrostatically attracted to the outer peripheral surface facing the photosensitive drum 101 and the transfer material is brought into contact with the photosensitive drum 101. As a result, the transfer material is transported to the transfer position by the transfer transport belt 11a, and the toner image on the photosensitive drum 101 is transferred.
[0042]
At the most upstream position of the transfer / conveyance belt 11a, a suction roller 153 for holding the transfer material with the belt 11a and adsorbing the transfer material to the transfer / conveyance belt 11a is disposed. When the transfer material is conveyed, a bias voltage is applied to the attraction roller 153 to form an electric field between the attraction roller 153 and the opposing grounded attraction roller 153. To generate an electrostatic attraction force between them.
[0043]
<Color image recording / monochrome image recording switching configuration>
The operation when performing color image recording and monochrome image recording in the present embodiment will be described.
[0044]
In the case of performing color image recording, the photosensitive drums 101C, 101Y, 101M, and 101Bk for four colors are moved by the developing separation plate 16 to a position where the developing rollers 103C, 103Y, 103M, and 103Bk are in contact with each other. Visual images are formed on the images formed on the drums 101C, 101Y, 101M, and 101Bk by using the developers transported from the image writing devices 106C, 106Y, 106M, and 106Bk by the developing rollers 103C, 103Y, 103M, and 103Bk. . Thereafter, the image formed on the photosensitive drum 101 is transferred onto a transfer material by the transfer devices 102C, 102Y, 102M, and 102Bk, and a fixing unit 152 fixes a color image.
[0045]
On the other hand, when monochrome image recording using only the black photosensitive drum 101Bk is selected, only the image writing device 106Bk is used in order to reduce the performance deterioration of the image writing devices 106C, 106Y, and 106M unnecessary for image formation. To form an image. Therefore, at the time of monochrome recording, as shown in FIG. 2, the photosensitive drum 101Bk of Bk only and the developing roller 103Bk are moved by the developing separation plate 16 so as to abut on the image formed on the photosensitive drum 101Bk. Then, a visual image is formed using the developer transported from the image writing device 106Bk by the developing roller 103Bk. Thereafter, the image formed on the photosensitive drum 101Bk is transferred onto a transfer material by the transfer device 102Bk, and the Bk monochrome image is fixed by the fixing unit 152.
[0046]
<Image forming operation>
[Example 1]
The operation of the above-described image forming apparatus when an image forming request is issued from an external device will be described with reference to a flowchart shown in FIG.
When an image forming request is issued from the external device, first, the total number of image forming transfer materials in one print job and the number of transfer materials for which only monochrome data exists and which can be used for monochrome image formation are acquired from the external device (S601).
[0047]
From the respective data, when the total number of image forming transfer materials is α0, the monochrome (single color) image forming transfer material number is β0, and the ratio of the monochrome image forming transfer material number to the total image forming transfer material is γ0,
γ0 = β0 / α0
The ratio γ of the number of monochrome image forming transfer materials to the total number of image forming transfer materials is determined (S602).
[0048]
Then, the calculation result γ0 of the ratio of the number of monochrome image forming transfer materials to the total number of image forming transfer materials is compared with a predetermined value M0 previously determined and written in the ROM (S603), and when M0 <= γ0 In step S604, the image forming operation is performed while switching between the color image forming mode for the transfer material having the color (multiple color) image and the monochrome image forming mode for the transfer material having only the monochrome image during the job operation. ).
[0049]
If the comparison result is M0> γ0, the image forming operation in the color image forming mode is performed on all the image forming transfer materials (S605).
[0050]
According to the present exemplary embodiment, the operation time of the photosensitive drum and the developing roller is not separated or abutted for the image forming operation during one print job operation, so that the operation time is shortened and the image forming operation with high productivity is performed. Equipment can be provided.
[0051]
[Example 2]
A second embodiment in the case where an image forming request is issued from an external device in the apparatus described in the first embodiment will be described with reference to a flowchart shown in FIG.
[0052]
When an image forming request is issued from an external device, first, the number of transfer materials for which color data exists in one job and color image formation is required from the external device, and the number of transfer materials for which monochrome data only exists and monochrome image formation is sufficient. It is acquired (S611).
[0053]
From the respective data, when the number of color (multiple color) image forming transfer materials is α1, the number of monochrome image forming transfer materials is β1, and the ratio of the number of monochrome image forming transfer materials to the number of color image forming transfer materials is γ1,
γ1 = β1 / α1
The ratio γ1 of the number of monochrome image forming transfer materials to the number of color image forming transfer materials is determined (S612).
[0054]
Then, the calculation result γ1 of the ratio of the number of monochrome image forming transfer materials to the number of color image forming transfer materials is compared with a predetermined value M1 previously determined and written in the ROM, and when M1 = <γ1, The image forming operation is performed while switching between the color image forming mode for the transfer material having a color image and the monochrome image forming mode for the transfer material having only a monochrome image during the job operation (S614).
[0055]
When the comparison result is M1> γ1, the image forming operation in the color image forming mode is performed on all the image forming and transferring materials (S615).
[0056]
According to the present exemplary embodiment, the operation time of the photosensitive drum and the developing roller is not separated or abutted for the image forming operation during one job operation, so that the operation time is reduced and the image forming apparatus with high productivity is achieved. Can be provided.
[0057]
[Example 3]
Third Embodiment A description will be given of a third embodiment in which an image forming request is issued from an external device in the apparatus described in the first embodiment with reference to a flowchart illustrated in FIG.
[0058]
When an image forming request is issued from an external device, first, the number of transfer materials for which color data exists in one job and color image formation is required from the external device, the number of transfer materials for which only monochrome data exists and monochrome image formation is sufficient, A predetermined value M2 to be compared with the calculated value of the ratio of the number of monochrome image forming transfer materials to the number of color image forming transfer materials for acquiring the color image forming operation or the monochrome image forming operation is acquired (S621).
[0059]
From the respective data, when the number of color image forming and transferring materials is α2, the number of monochrome image forming and transferring materials is β2, and the ratio of the number of monochrome image forming and transferring materials to the number of color image forming and transferring materials is γ2,
γ2 = β2 / α2
Then, the ratio γ2 of the number of monochrome image forming transfer materials to the number of color image forming transfer materials is determined (S622).
[0060]
Then, the calculation result γ2 of the ratio of the number of monochrome image forming transfer materials to the number of color image forming transfer materials is compared with the obtained predetermined value M2 (S623). If M2 = <γ2, a color image exists. The image forming operation is performed while switching between the color image forming mode for the transfer material and the monochrome image forming mode for the monochrome image-only transfer material during the job operation (S624).
[0061]
If the comparison result is M2> γ2, the image forming operation in the color image forming mode is performed on all the image forming and transferring materials (S625).
[0062]
According to the present exemplary embodiment, the operation time of the photosensitive drum and the developing roller is not separated or abutted for the image forming operation during one job operation, so that the operation time is reduced and the image forming apparatus with high productivity is achieved. Can be provided.
[0063]
【The invention's effect】
As described above, according to the present invention, in the multi-color image forming mode, the first image forming means for forming an image by controlling the developing roller of the developing means and the image carrier to be in contact with each other; In the mode, the second image forming means for forming an image by controlling the developing roller of the developing means and the image carrier to be separated from each other, and at the start of one print job, the total number of image forming transfer materials in the print job; Acquiring means for acquiring the number of multi-color image forming transfer materials to be image-formed in the multi-color image forming mode and the number of single-color image forming and transferring materials to be image-formed in the single-color image forming mode; Since there are first calculating means for calculating the ratio of the number of image forming transfer materials and second calculating means for calculating the ratio of the number of single-color image forming transfer materials to the number of multi-color image forming transfer materials, a multi-color image By performing only the multi-color image forming operation in accordance with the ratio of the single-color image forming within one job in which the forming and the single-color image forming are mixed, the operation time due to the elimination of the need to switch between the multi-color image forming and the single-color image forming And an image forming apparatus with high productivity can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic side sectional view of an image forming apparatus according to the present invention, and is an explanatory diagram illustrating a state in which color printing is performed.
FIG. 2 is a schematic side sectional view of the image forming apparatus according to the present invention, illustrating a state in which monochrome recording is performed.
FIGS. 3A and 3B are schematic diagrams illustrating a developing separation state of the image forming apparatus, wherein FIG. 3A illustrates a contact operation of the developing apparatus and FIG.
FIGS. 4A and 4B are schematic diagrams of a tandem type color image forming apparatus provided with a developing / separating mechanism. FIG. 4A shows a case where a color image is formed, FIG. 4B shows a case where a monochrome image is formed, and FIG. FIG. 5 is a diagram illustrating a state in which a drum and a developing roller are all separated.
FIG. 5 is a diagram illustrating a flowchart for explaining the first embodiment when an image forming request is issued from an external device.
FIG. 6 is a flowchart illustrating a second embodiment when an image forming request is issued from an external device.
FIG. 7 is a flowchart illustrating a third embodiment when an image forming request is issued from an external device.
[Explanation of symbols]
11 Transfer material transport section
11a Transfer conveyor belt
11b Transfer transport belt drive roller
11c, 11d, 11e Transfer conveyor belt driven roller
16 Developing separation plate
101C, 101Y, 101M, 101Bk Photoconductor drum
102C, 102Y, 102M, 102Bk transfer device
103C, 103Y, 103M, 103Bk developing roller
104C, 104Y, 104M, 104Bk charging roller
106C, 106Y, 106M, 106Bk Image Writing Apparatus
108C, 108Y, 108M, 108Bk scanner unit
140 feed roller pair
150 Paper feed unit
151 Pickup roller
152 fixing unit
153 Suction roller

Claims (11)

At least one or more image carriers that are rotationally driven, a latent image unit that forms an electrostatic latent image on the image carrier, and a developing roller that supplies toner that is a developer to the electrostatic latent image Developing means for adhering toner to the image carrier to form a toner image, transferring means for transferring the toner image to a transfer material, and separating or abutting the developing roller of the developing means and the image carrier. Developing separation means for carrying out, a transfer material suction means for suctioning the recording paper carried on the transfer material onto a conveyance belt, and a conveyance means for conveying the transfer material sucked by the transfer material suction means in a predetermined direction. An image forming apparatus that forms a toner image by a fixing unit that thermally fixes the toner transferred by the transfer unit to the transfer material conveyed by the conveyance unit;
A first image forming unit configured to control the developing roller of the developing unit and the image carrier in a contact state to form an image during a multi-color image forming mode;
A second image forming unit configured to form an image by controlling the developing roller of the developing unit and the image carrier to be separated from each other during a single-color image forming mode;
At the start of one print job, the total number of image forming transfer materials in the print job, the number of multi-color image forming transfer materials to be formed in the multi-color image forming mode, and the single color to be formed in the single-color image forming mode Acquiring means for acquiring the number of image forming transfer materials,
First calculating means for calculating a ratio of the number of the monochrome image forming transfer materials to the total number of image forming transfer materials,
And a second calculating means for calculating a ratio of the number of the single-color image forming transfer materials to the number of the multi-color image forming transfer materials. When the calculation result of the ratio of the number of the single-color image forming transfer materials to the total number of the image forming transfer materials by the first calculating unit is equal to or less than a predetermined value, the image forming on the transfer material in one print job is performed. 2. The image forming apparatus according to claim 1, wherein the first image forming unit that forms an image in the multi-color image forming mode forms an image. If the calculation result of the ratio of the number of the single-color image forming transfer materials to the total number of the image forming transfer materials by the first calculating unit is equal to or larger than a predetermined value, the image for the transfer material in one print job is determined. Forming is performed by a first image forming unit that forms an image in the multi-color image forming mode and a second image forming unit that forms an image in the single-color image forming mode in accordance with an image forming mode designated for each transfer material. The image forming apparatus according to claim 1, wherein image formation is performed by switching between the image forming unit and the image forming unit. When the calculation result of the ratio of the number of the single-color image forming transfer materials to the number of the multi-color image forming transfer materials by the second calculating unit is equal to or smaller than a predetermined value, the transfer within one print job is performed. 2. The image forming apparatus according to claim 1, wherein the image forming is performed by the first image forming unit that forms an image in the multi-color image mode. If the calculation result of the ratio of the number of the single-color image forming transfer materials to the number of the multi-color image forming transfer materials by the second calculating unit is equal to or larger than a predetermined value, the transfer within one print job is performed. The first image forming unit forms an image in the multi-color image forming mode in accordance with an image forming mode designated for each transfer material, and forms an image in the single-color image forming mode. The image forming apparatus according to claim 1, wherein image formation is performed by switching between the image forming unit and the second image forming unit. 2. The image forming apparatus according to claim 1, wherein a predetermined value to be compared with a calculation result of the ratio of the number of transfer sheets for monochrome image formation by the first and second calculation units can be set from the outside. 3. In an image forming method for forming an image by transferring an image formed by an image forming unit including a plurality of image carriers to a transfer material,
When an image forming request is issued from an external device, first, an obtaining step of obtaining the total number of image forming transfer materials and the number of monochromatic image forming transfer materials in one print job from the external device;
A calculating step of calculating a ratio of the number of the single-color image forming transfer materials to the total number of the image forming transfer materials,
A comparison step of comparing the calculation result γ0 of the ratio of the number of monochrome image forming transfer materials with a predetermined value M0;
If the comparison result in the comparison step is M0 <= γ0, the multi-color image forming mode is set for a transfer material having a multi-color image, the mono-color image formation mode is set for a transfer material having only a single color image, A first image forming step of performing an image forming operation while switching during operation;
A second image forming step of performing an image forming operation in a multi-color image forming mode on all the image forming and transferring materials when the comparison result in the comparing step is M0> γ0. Image forming method. In an image forming method for forming an image by transferring an image formed by an image forming unit including a plurality of image carriers to a transfer material,
When an image forming request is issued from the external device, first, an obtaining step of obtaining the number of multi-color image forming transfer materials and the number of single-color image forming transfer materials in one job from the external device;
Calculating a ratio of the number of single-color image forming transfer materials to the number of multi-color image forming transfer materials;
A comparison step of comparing a calculation result γ1 of a ratio of the number of the single-color image forming transfer materials to the number of the multi-color image forming transfer materials with a predetermined value M1;
If the comparison result in the comparison step is M1 = <γ1, the multi-color image forming mode is set for the transfer material having the multi-color image, the single-color image formation mode is set for the transfer material having only the single-color image, A first image forming step of performing an image forming operation while switching during operation;
A second image forming step of performing an image forming operation in a multi-color image forming mode on all the image forming and transferring materials when the comparison result in the comparing step is M1> γ1. Image forming method. In an image forming method for forming an image by transferring an image formed by an image forming unit including a plurality of image carriers to a transfer material,
When an image forming request is issued from an external device, first, the number of multi-color image forming transfer materials and the number of single-color image forming transfer materials in one job from the external device, and whether the multi-color image forming operation or the single-color image forming operation is performed. An acquiring step of acquiring a predetermined value M2 to be compared with a calculated value of a ratio of the number of the single-color image forming transfer materials to the number of the multi-color image forming transfer materials,
Calculating a ratio of the number of the single-color image forming transfer material to the number of the multi-color image forming transfer material;
A comparison step of comparing a calculation result γ2 of a ratio of the number of the single-color image formation transfer materials to the number of the plurality of image formation transfer materials with the predetermined value M2;
If the comparison result in the comparison step is M2 = <γ2, the multi-color image forming mode is set for a transfer material having a plurality of color images, the single-color image formation mode is set for a transfer material having only a single color image, A first image forming step of performing an image forming operation while switching during operation;
A second image forming step of performing an image forming operation in a multi-color image forming mode on all of the image forming and transferring materials when the comparison result in the comparing step is M2> γ2. Image forming method. 10. A program for executing each step according to claim 7, 8 or 9 using a computer. A computer-readable recording medium on which a program for executing each step according to claim 7, 8 or 9 is recorded.

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