JP3695271B2 - Image forming apparatus and image forming method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is configured such that a multi-bin unit (multiple bin unit: a multi-stage paper discharge device) capable of sorting and discharging image-formed paper into a plurality of bins is integrated or connected to the multi-bin unit. The present invention relates to an image forming apparatus and an image forming method in the apparatus.
[0002]
[Prior art]
Conventionally, a multi-bin unit having a plurality of bins is incorporated into an image forming apparatus such as a printer, a copying machine, or a facsimile, or multi-bin units are connected and arranged, and the multi-bin unit is used as a sorter. In this case, a plurality of sheets on which images have been formed are distributed to a plurality of units and discharged for each bin of the multi-bin unit. That is, when the image forming command received by the image forming apparatus includes information related to the sorting process, a plurality of pages of the document to be printed are formed, and the number 1 bin, the number 2 bin, etc. Sorted paper bundles are obtained by sequentially sorting and discharging to bins having bin numbers corresponding to the number of copies to be printed.
[0003]
In recent years, this multi-bin unit is also used as a mailbox. In this case, each bin is assigned as an individual output bin. When the image forming command received by the image forming apparatus includes personal destination identification information, more specifically, image data including the output destination bin number in the header is sent from an external device such as a host computer. When the image forming apparatus has received the image, the image forming apparatus discharges the sheet on which the image is formed in the bin having the designated bin number. As a result, the sheet addressed to the individual is not mixed with the sheet addressed to the other person, and the sheet addressed to the user can be easily found. Furthermore, the use of the multi-bin unit as a mailbox is particularly useful when a single network forming network is used to share one image forming apparatus.
[0004]
[Problems to be solved by the invention]
By the way, in order to perform the sorting process and the mail process using the multi-bin unit, it is necessary to reliably detect the discharge of the paper to each bin. Conventionally, a pair of discharge sensors for detecting the discharge of the paper is used. 1 in each bottle. However, in order to provide the discharge sensor in each bin, there is a problem that the interval (bin pitch) between the bins is widened and the size of the multi-bin unit is increased due to the sensor mounting layout. In addition, the same number of discharge sensors as the number of bins is required, which increases the cost of the apparatus.
[0005]
In order to solve such problems, for example, in the invention described in Japanese Patent Laid-Open No. 8-202097, the common conveyance path of each bin is divided into a plurality of sections, and a discharge sensor is provided in each section. The discharge sensor detects the discharge of the paper in each bin every time. Thus, even when one-way folding sorting is performed from the upstream bin to the downstream bin, it is possible to detect the discharge of the sheet with a small number of sensors. Also, during folding sorting, the paper is discharged in advance to the bin on the upstream side of the bin on the downstream side of the common conveyance path. However, since the bins are different from each other, Paper discharge can be reliably detected by the provided sensor.
[0006]
However, even in the above-mentioned proposal example, it is necessary to provide discharge sensors as many as the number of sections, and there is still room for improvement in order to reduce the size and cost of the multi-bin unit.
[0007]
Further, the above proposed example considers only folding sorting and does not consider mail processing at all. In particular, when the multi-bin unit is made to function as a mailbox, the bin number of the discharge destination is not uniquely determined, and the following problems may occur within the same category. The problem will be described below with reference to FIG.
[0008]
FIG. 11 is a schematic diagram illustrating the operation of the proposed multi-bin unit. In this multi-bin unit, a plurality of bins are branched from the common conveyance path 32 at different branch positions, and the sheet conveyed along the common conveyance path 32 is one of the plurality of bins. The bottles can be selectively discharged. Further, among the plurality of bins, for example, bin numbers BIN2 to BIN5 are classified as one section, and a discharge sensor 6 is provided corresponding to this. In the discharge sensor 6, a light projecting unit 61 and a light receiving unit 62 are disposed opposite to each other in the vicinity of the branch position, and the four bins BIN2 to BIN5 are irradiated with the light beam L in a skewered manner. It is detected that the sheet is discharged from the common conveyance path 32 to the bins BIN2 to BIN5.
[0009]
Here, for example, when two sheets P1 and P2 are discharged to the bins BIN2 and BIN4, respectively, after the previous sheet P1 is transported toward the designated bin BIN2, the subsequent sheet P2 is continuously transferred from the bin BIN2. Also consider the case of transporting toward the upstream bin BIN4. In this case, as shown in FIG. 5A, both sheets P1, P2 are conveyed along the common conveyance path 32 in a state of being separated by a predetermined interval. However, when the conveyance distances of both sheets P1, P2 are compared, The transport distance of the subsequent paper P2 is shortened by the amount that the discharge destination (bin BIN4) of the second paper P2 is located upstream from the discharge destination (BIN2) of the previous paper. As a result, as shown in FIG. 5B, the two sheets P1, P2 may overlap on the optical path of the light beam L, and the sheet discharge may not be detected accurately by the discharge sensor 6.
[0010]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an image forming apparatus in which a multi-bin unit capable of sorting and discharging paper into a plurality of bins is integrated or connected to the multi-bin unit. The present invention relates to an image forming method in the apparatus, and an object thereof is to reliably detect discharge of a sheet with a single discharge sensor for all bins.
[0011]
[Means for Solving the Problems]
The present invention has a plurality of bins that are branched at different branch positions with respect to a common conveyance path, and the sheet conveyed along the common conveyance path is one of the plurality of bins. While selectively discharging to the bin, the discharge sensor provided near the plurality of branch positions irradiates the plurality of bins with light beams in a skewered manner, based on transmission / shading of the light beams from the common conveyance path. In order to achieve the above object, the present invention relates to an image forming apparatus in which a multi-bin unit that detects that paper is discharged into a bin is integrated, or connected to the multi-bin unit. The configuration is as follows.
[0012]
An image forming apparatus according to the present invention includes an image forming unit that forms an image on a sheet, a conveying unit that conveys the sheet formed by the image forming unit to the multi-bin unit, and a control that controls the image forming unit. And when the image is formed in a predetermined image forming mode set in advance, when a plurality of sheets overlap on the optical path of the light beam, the control unit changes the image forming mode in the image forming unit. Thus, overlap of sheets on the optical path is avoided.
[0013]
In the image forming apparatus configured as described above, when an image is formed in a predetermined image forming mode set in advance, a plurality of sheets are overlapped on the optical path of the light beam. When the discharge cannot be detected, the image forming mode in the image forming unit is changed to avoid the overlap of sheets on the optical path. Therefore, when the light beam is blocked, there is always only one sheet on the light path of the light beam, and the sheet discharge to the bin is reliably detected by the single discharge sensor.
[0014]
Another aspect of the present invention includes a plurality of bins that are branched and provided at different branch positions with respect to the common conveyance path, and a sheet conveyed along the common conveyance path is fed to the plurality of bins. While selectively discharging to one of the bins, the discharge sensors provided in the vicinity of the plurality of branch positions irradiate the plurality of bins with light beams in a skewered manner based on transmission / shielding of the light beams. An image forming method for conveying a sheet on which an image is formed by an image forming unit with respect to a multi-bin unit that detects that a sheet is discharged from a common conveyance path to a bin. Determining whether or not a plurality of sheets overlap each other on the optical path of the light beam when image formation is performed in the predetermined image forming mode, and when determining that the sheets overlap on the optical path, Change the image forming mode in adult means and a step to avoid the overlapping of the sheets in the optical path.
[0015]
In the invention thus configured, first, prior to actual image formation, when image formation is performed in a predetermined image formation mode set in advance, it is determined whether or not a plurality of sheets overlap on the optical path of the light beam. This is nothing but determining whether or not it is possible to detect paper discharge to the bin by the discharge sensor. Then, as a result of the determination, when it is determined that the sheets overlap on the optical path, the image forming mode in the image forming unit is changed, and the overlap of the sheets on the optical path is avoided. Therefore, when the light beam is blocked, there is always only one sheet on the optical path of the light beam, and the sheet discharge to the bin is reliably detected by the single discharge sensor.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an example of an image forming system including an image forming apparatus according to the present invention. The image forming system includes an image forming apparatus 1 according to an embodiment of the present invention, a finisher 2 disposed adjacent to the image forming apparatus 1, and a multi-bin unit 3 disposed above the image forming apparatus 1. , And an optional paper feed cassette 4 disposed below the image forming apparatus 1. Thus, the image forming apparatus 1 is configured to be connectable to the multi-bin unit 3.
[0017]
The image forming apparatus 1 prints a full-color image on a sheet by superposing four color toners of yellow (Y), cyan (C), magenta (M), and black (K), or black (K) toner. A monochrome image is printed on a sheet using only a sheet, and as shown in the figure, a photoconductor unit 12, an exposure unit 13, a transfer unit 14, a fixing unit 15 and a paper supply / discharge unit 16 are provided inside the case 11. Is provided.
[0018]
The photoconductor unit 12 includes a photoconductor 121 that can be rotated counterclockwise on the paper surface of the figure, and further, a charging roller 122 as a charging unit, a developing unit, and the like around the photoconductor 121 along the rotation direction. Developing units 123Y, 123C, 123M, and 123K, and a cleaning unit 124 are disposed. Then, a laser beam is irradiated from the exposure unit 13 toward the outer peripheral surface of the photosensitive member 121 charged by the charging roller 122 to form an electrostatic latent image corresponding to an image forming command given from the outside of the apparatus as will be described later. The
[0019]
The electrostatic latent image thus formed is developed with toner by the developing unit. That is, in this embodiment, the developing unit 123Y for yellow, the developing unit 123C for cyan, the developing unit 123M for magenta, and the developing unit 123K for black are arranged in this order along the photoconductor 121 as the developing unit. ing. These developing units 123Y, 123C, 123M, and 123K are configured so as to be able to come into contact with and separate from the photosensitive member 121, respectively, and the four developing units 123Y, 123, One of the developing devices 123M, 123C, and 123B selectively contacts the photoconductor 121 to reveal the electrostatic latent image on the photoconductor 121. Thus, the photoconductor unit 12 forms a toner image corresponding to the image formation command on the photoconductor 121.
[0020]
The toner image developed by the developing unit is primarily transferred onto the intermediate transfer belt 141 of the transfer unit 14 in a primary transfer region located between the black developing device 123K and the cleaning unit 124.
[0021]
The transfer unit 14 includes a plurality of rollers, an intermediate transfer belt 141 stretched over the rollers, and a secondary transfer roller 142 that secondarily transfers the intermediate toner image transferred to the intermediate transfer belt 141 onto a sheet. I have. In this embodiment, the maximum A3 size toner image can be transferred onto the intermediate transfer belt 141, and two sheets can be transferred simultaneously for the A4 size or four sheets for the postcard size.
[0022]
When a color image is transferred to a sheet, each color toner image formed on the photosensitive member 121 is superimposed on the intermediate transfer belt 141 to form a color image, and the paper supply / discharge unit 16 supplies paper. The unit 161 takes out the paper from the cassette 162, the manual feed tray 163, or the optional paper feed cassette 4 and conveys it to the secondary transfer area. Then, a color image is secondarily transferred onto this paper to obtain a full color image. In addition, when transferring a monochrome image to a sheet, only a black toner image is formed on the intermediate transfer belt 141 on the photosensitive member 121, and the sheet has been conveyed to the secondary transfer area in the same manner as in the case of a color image. To obtain a monochrome image. Thus, in this embodiment, the intermediate transfer belt 141 functions as the “image carrier” of the present invention, and the image forming means for forming an image on the sheet by the photosensitive unit 12, the exposure unit 13, and the transfer unit 14 is configured. Has been.
[0023]
The sheet on which the toner image is transferred by the transfer unit 14 is disposed downstream of the secondary transfer region along a predetermined sheet feeding path (two-dot chain line) by the sheet feeding unit 161 of the sheet feeding / discharging unit 16. The toner image on the conveyed paper is conveyed to the fixing unit 15 and fixed on the paper. Then, the paper is further conveyed to the paper discharge unit 164 along the paper feed path.
[0024]
The paper discharge unit 164 has two paper discharge paths 164a and 164b. One paper discharge path 164a extends from the fixing unit 15 to the standard discharge tray, and the other paper discharge path 164b is connected to the paper discharge path 164a. The paper feed section 165 and the multi-bin unit 3 extend substantially in parallel. Three pairs of rollers are provided along these paper discharge paths 164a and 164b, and the fixed paper is discharged toward the standard discharge tray, finisher 2 or multibin unit 3, or the other side thereof. In addition, the sheet is conveyed to the refeed unit 165 side in order to form an image. Thus, the paper discharge unit 164 functions as the “conveying means” of the present invention.
[0025]
As shown in FIG. 1, the refeed unit 165 is configured to feed the sheet reversely conveyed from the sheet discharge unit 164 as described above along the refeed path (two-dot chain line). The pair is conveyed to the pair 166, and is composed of three refeed roller pairs disposed along the refeed path. In this way, by returning the paper conveyed from the paper discharge unit 164 to the gate roller pair 166 along the refeed path, the non-image forming surface of the paper faces the intermediate transfer belt 141 in the paper supply unit 161. The image can be secondarily transferred to the surface.
[0026]
Next, the configuration of the finisher 2 will be briefly described with reference to FIG. A paper feed port (not shown) for receiving the paper discharged from the image forming apparatus 1 is provided on the side surface of the finisher 2. Further, a punch portion 23 is provided in the vicinity of the paper feed port for punching holes in the paper, and punch holes are made in the paper as necessary. Then, the sheet carried into the finisher 2 is conveyed to the non-sorting tray 24 or is conveyed to the intermediate tray 21 by the conveying mechanism 25. The intermediate tray 21 temporarily stores sheets of paper that have been carried in from the image forming apparatus 1. When a predetermined number of sheets are stored, the intermediate tray 21 staples a sheet bundle of these sheets as necessary. After performing the stapling process by 26, the paper is discharged to the main tray 22.
[0027]
FIG. 2 is a diagram schematically showing the configuration of the multi-bin unit. The multi-bin unit 3 has a common conveyance path 32 that conveys the image-formed paper that has been conveyed into the unit by the paper discharge unit (conveying means) 164 of the image forming apparatus 1. The common transport path 32 branches at different branch positions, and ten bins BIN1 to BIN10 are stacked in the vertical direction. In this embodiment, the bin BIN10 is arranged on the upstream side of the common conveyance path 32, and the bins BIN9 to BIN1 are arranged in this order as proceeding to the downstream side (upward side in the drawing).
[0028]
Further, branching claws 33 for switching the paper discharge destinations corresponding to each branching position on a one-to-one basis are provided swingably. A plurality of sheets conveyed along the common conveyance path 32 are positioned by swinging and positioning each of the branching claws 33 by a discharge destination switching control unit 315 (FIG. 4) of the multi-bin unit controller 31 described later. Are selectively discharged into one of the bins BIN1 to BIN10.
[0029]
Each of the bins BIN1 to BIN10 detects a sheet detection sensor S31 that detects whether or not a sheet is stored in the bin, and whether or not the sheet storage amount in the bin has reached a preset upper limit amount. A pair of storage limit detection sensors S32 is provided. Further, a single discharge sensor S33 is provided for detecting the discharge of the paper to each bin BIN1 to BIN10.
[0030]
The discharge sensor S33 includes a light projecting portion S33a disposed at the inner bottom portion of the unit body 34 and a light receiving portion S33b disposed at the inner top portion of the unit body 34. The light projecting portion S33a is in the vicinity of the branch position. Then, all the bins BIN1 to BIN10 are irradiated with the light beam L in a skewered manner, and the light beam L can be received by the light receiving unit S33b disposed opposite to the light projecting unit S33a. For this reason, while the paper is being ejected to the bin while traversing the optical path of the light beam L, the light beam L is shielded. On the other hand, when the paper ejection to the bin is completed, the paper passes through the optical path and the light beam L Is received by the light receiving unit S33b and the transmission of the light beam L is detected. Thus, the paper discharge to the bin is detected by the discharge sensor S33.
[0031]
FIG. 3 is a diagram showing an electrical configuration of the image forming system of FIG. In this image forming system, a main controller 17 and a sub controller 18 are provided in the image forming apparatus 1 as shown in FIG. Among these, the main controller 17 includes a CPU, an image memory, a communication interface, and the like. When receiving an image formation command (a signal indicating a print request content) from the host computer 5, the main controller 17 receives an operation instruction of each unit of the image forming apparatus 1. It is converted into job data (printing information) in a suitable format and given to the sub-controller 18. In particular, as will be described later, the main controller 17 determines whether or not conditions (1) and (2) to be described later are satisfied in the multi-bin unit 3, creates job data according to the determination result, It is given to the controller 18. Thus, the main controller 17 functions as the “control unit” of the present invention.
[0032]
The sub-controller 18 that has received the job data includes a CPU, a ROM, a RAM, a communication interface, and the like, and controls each unit of the image forming apparatus 1 according to the job data. Correspondingly, the sub-controller 18 gives various control signals to the finisher controller 29 by serial communication, gives various control signals to the multi-bin unit controller 31, and further supplies them to the optional paper feed cassette controller 41. By giving various control signals, each part of the finisher 2, the multi-bin unit 3 and the optional paper feed cassette 4 is controlled to execute a printing process corresponding to the image formation command.
[0033]
FIG. 4 is a diagram showing an electrical configuration of a multi-bin unit controller provided in the multi-bin unit main body in order to control the multi-bin unit shown in FIG. In the multi-bin unit controller 31, various information is given to the CPU 312 from the sub-controller 18 of the image forming apparatus 1 through the communication interface 311 together with detection signals from the sensor groups S 31 to S 34 provided in the multi-bin unit 3. It is configured. The CPU 312 controls each part of the multi-bin unit according to a program stored in advance in the ROM 313 based on these signals and information. Reference numeral S34 denotes a carry-in detection sensor that is disposed in the vicinity of the paper carry-in port 341 of the multi-bin unit 3 and detects paper carry-in.
[0034]
In order to control each part of the multi-bin unit 3, the following control unit is electrically connected to the CPU 312.
[0035]
(a) Main motor drive control unit 314: Drives and controls a main motor (not shown) that is a drive source of each part of the multi-bin unit 3.
[0036]
(b) Discharge destination switching control unit 315: The branch claw 33 is driven to swing to select a paper discharge destination from a plurality of bins BIN1 to BIN10.
[0037]
The multi-bin unit controller 31 changes the AC power supplied through the AC input unit 316 to a direct current having a predetermined voltage by the power source unit 317 and serves as a power source in the multi-bin unit 3. In particular, in this embodiment, power supply from the AC input unit 316 is image-formed by controlling conduction / non-conduction of the AC relay 317a provided in the power supply unit 317 based on a relay control signal from the image forming apparatus 1. The apparatus 1 is configured to be remotely controlled.
[0038]
Note that reference numeral 318 in the figure is a RAM for temporarily storing control data for controlling each part of the multi-bin unit 3 and a calculation result in the CPU 312.
[0039]
Next, an image forming operation in the image forming system configured as described above will be described with reference to FIGS. FIG. 5 is a flowchart showing the image forming operation. FIGS. 6 and 7 are diagrams schematically showing the image forming operation executed according to the flowchart of FIG. 5 and the sheet discharging operation in the multi-bin unit. It is.
[0040]
In this image forming apparatus 1, when receiving an image formation command (a signal indicating a print request content) from the host computer 5, the main controller 17 prints the print request content included in the image formation command, for example, paper size, monochrome / color, single-sided / It is determined whether or not continuous discharge to the multi-bin is performed based on both sides and the discharge destination bin number (step ST1). As a result of the determination, when the sheets are not continuously discharged to the multi-bin unit 3, the above-described problem does not occur, and an image is formed in a preset image forming mode (step ST2).
[0041]
If it is determined that continuous discharge to the multi-bin unit 3 is performed based on the determination result (step ST1), the discharge destination (bin number) of each sheet is further checked based on the contents of the print request (step ST3), and similarly to step ST2. It is examined whether or not a plurality of sheets overlap each other on the optical path of the light beam L when image formation is performed in a predetermined image formation mode set in advance (step ST4). More specifically, the main controller 17 has the following two conditions:
(1) The bin from which the second sheet is discharged out of the two sheets that are continuously discharged back and forth is positioned upstream of the bin from which the previous sheet is discharged in the common conveyance path 32. And the condition
(2) A condition that the bin from which the first sheet is discharged and the bin from which the second sheet is discharged are separated by two bins or more
If both are satisfied, it is determined that a plurality of sheets overlap on the optical path. On the other hand, if at least one of the conditions is not satisfied, it is determined that the plurality of sheets do not overlap on the optical path.
[0042]
In this embodiment, the condition (2) is defined as described above based on the bin pitch of the multi-bin unit 3. However, when the bin pitch is set to be narrower, the number of separated bins in the condition (2) is further increased. May be set as “2”, or may be set to “3” or more depending on the bin pitch. In short, the number of separation bins can be set to a predetermined value of “2” or more according to the configuration of the multi-bin unit 3. Further, the image forming mode can be set in advance so that the interval between consecutive sheets for each sheet size is different from each other. For example, the paper interval when the B5 size paper is continuously conveyed to the multi-bin unit 3 can be set wider than the paper interval of the A4 size. In this case, the condition (2 ) May be changed. Further, the condition (2) may be determined based on the distance between the bin from which the previous sheet is discharged and the bin from which the subsequent sheet is discharged, instead of the number of separation bins.
[0043]
If it is determined in step ST4 that the sheets do not overlap, the process proceeds to step ST2 to form an image in a preset image forming mode as shown in the specific example of FIG. On the other hand, if it is determined that a plurality of sheets are overlapped on the optical path of the light beam L, the process proceeds to step ST5, and a subsequent image is formed while being shifted backward from the normal formation position as shown in the specific example of FIG. In this manner, the overlapping of sheets on the optical path is avoided by changing the image forming position from the image forming position in the preset image forming mode.
[0044]
Here, the determination step (step ST4) and the image forming mode according to the determination result will be described in detail with specific examples. In order to facilitate the understanding of the contents of this embodiment, a single-sided monochrome document of A4 size is continuously discharged one by one into bin BIN1 located at the most downstream and bin BIN10 located at the most upstream. It is taken up. The bin from which the second sheet is discharged out of the two sheets that are continuously discharged back and forth is located on the downstream side in the common conveyance path with respect to the bin from which the first sheet is discharged (A). A specific example (FIG. 6) and (B) a specific example (FIG. 7) located upstream in the common conveyance path from the bin where the first sheet is discharged will be described.
[0045]
<Specific example (A)>
FIG. 6 is a diagram schematically illustrating the operation of the image forming apparatus and the multi-bin unit when the subsequent paper discharge destination is located downstream of the bin from which the previous paper is discharged in the common transport path. It is. In this specific example (A), as shown in FIG. 6A, an image formation command for requesting printing of a monochrome image I1 on A4 size paper and discharging it to the bin BIN10, and a monochrome image I2 as A4. An image forming command is issued from the host computer 5 to the image forming apparatus 1 in this order in order to print the size paper and discharge it to the bin BIN1.
[0046]
When continuous discharge to the multi-bin is requested in this way, in the image forming apparatus 1, the main controller 17 checks the discharge destination (bin number) of each sheet based on the print request contents (step ST3). Then, it is determined whether or not both of the two conditions (1) and (2) are satisfied. In this specific example (A), although the condition (2) is satisfied, the condition (1) Is not satisfied, it is determined that the plurality of sheets do not overlap on the optical path of the light beam L.
[0047]
Based on the determination result, the main controller 17 uses two image formation commands in a format suitable for the operation instruction of each part of the apparatus in order to perform image formation according to a preset image formation mode. More specifically, the image I1 and the image I2 are converted into job data for transferring to A4 size paper, respectively.
[0048]
Upon receiving this job data, the sub controller 18 continuously forms images I1 and I2 corresponding to the respective documents on the intermediate transfer belt 41 as shown in FIG. It is transferred and fixed to I1) and P (I2) and further conveyed to the multi-bin unit 3.
[0049]
An image I1 is formed on the sheet P (I1) conveyed first to the multi-bin unit 3. When the sheet P (I1) is carried into the multi-bin unit 3, the bin BIN10 located on the most upstream side is formed. Immediately discharged. On the other hand, the sheet P (I2) (in which the image I2 is formed) carried into the multi-bin unit 3 with a slight delay from the sheet P (I1) is the previous sheet P as shown in FIG. Even after (I1) is discharged to the bin BIN10, it moves along the common transport path 32. After a further time has passed, the light beam L crosses the optical path for the first time and is discharged to the bin BIN1. Therefore, the sheets P (I1) and P (I2) are discharged to the corresponding bins without overlapping the sheets P (I1) and P (I2) on the optical path of the light beam L, and therefore reliably discharged by the discharge sensor S33. Paper discharge can be detected.
[0050]
Here, the case where the discharge destination of the previous paper P (I1) and the discharge destination of the subsequent paper P (I2) are illustrated is described as an example, but both discharge destinations are the same or close to each other Even in this case, the condition (1) is not always satisfied, and the discharge of the sheet can be reliably detected by the discharge sensor S33 in the same manner as in the specific example (A).
[0051]
<Specific example (B)>
FIG. 7 is a diagram schematically illustrating the operation of the image forming apparatus and the multi-bin unit when the discharge destination of the subsequent sheet is positioned on the upstream side in the common conveyance path with respect to the bin from which the previous sheet is discharged. It is. In this specific example (B), as shown in FIG. 6A, an image formation command for requesting printing of monochrome image I1 on A4 size paper and discharging to bin BIN1, and monochrome image I2 for A4 An image forming command is issued from the host computer 5 to the image forming apparatus 1 in this order in order to print the size paper and discharge it to the bin BIN10.
[0052]
When continuous discharge to the multi-bin is requested in this way, in the image forming apparatus 1, the main controller 17 checks the discharge destination (bin number) of each sheet based on the print request contents (step ST3). Then, it is determined whether or not both of the above two conditions (1) and (2) are satisfied. In this specific example (B), both conditions (1) and (2) are satisfied, When an image is formed in a preset image forming manner as in the specific example (A), it is determined that a plurality of sheets overlap on the optical path of the light beam L.
[0053]
Based on the determination result, the main controller 17 uses two image formation commands in a format suitable for the operation instructions of each part of the apparatus in order to avoid the overlap of sheets on the optical path. More specifically, the conversion is divided into job data for transferring the image I1 to A4 size paper and job data for transferring the image I2 to A4 size paper.
[0054]
Then, the sub-controller 18 that has received the first job data transfers and fixes it onto the paper P (I1) while forming only the image I1 on the intermediate transfer belt 41 as shown in FIG. Transport to the bin unit 3. When the next job data is received, the sub-controller 18 intermediates the image I2 so as to be positioned behind the image forming position (formation position of the image I2 in FIG. 6) in the preset image forming mode. While being formed on the transfer belt 41, it is transferred and fixed onto the paper P (I 2) and further conveyed to the multi-bin unit 3. By changing the image formation position in this way, the interval between the previous paper P (I1) and the subsequent paper P (I2) is increased.
[0055]
An image I1 is formed on the paper P (I1) that has been transported to the multi-bin unit 3 first, and the paper P (I1) is transported along the common transport path 32 when it is transported to the multi-bin unit 3. After that, it is discharged to the bin BIN1 located on the most downstream side. Thus, in order to transport the paper P (I1) to the downstream side, a relatively long transport time is required. In this embodiment, the image forming mode is controlled by changing the image forming position. Since the interval between the paper P (I1) and the subsequent paper P (I2) is widened, the subsequent paper P (I2) is on the optical path of the light beam L until the previous paper P (I1) is discharged to the bin BIN1. Never cross.
[0056]
Then, as shown in FIG. 9C, after the previous paper P (I1) is completely discharged to the bin BIN1, the subsequent paper P (I2) is discharged toward the bin BIN10 on the most upstream side. . Therefore, the sheets P (I1) and P (I2) are discharged to the corresponding bins without overlapping the sheets P (I1) and P (I2) on the optical path of the light beam L, and therefore reliably discharged by the discharge sensor S33. Paper discharge can be detected.
[0057]
Here, the case where the discharge destination of the previous paper P (I1) and the discharge destination of the subsequent paper P (I2) are illustrated is described as an example, but there are two or more paper discharge destinations. If they are separated, the image forming mode is changed in the same manner as in the specific example (B). However, if both paper discharge destinations are adjacent or the same, Condition (2) is not satisfied, and even if images are formed in the normal image formation mode, the sheets overlap on the optical path. Therefore, step ST2 is executed.
[0058]
As described above, according to this embodiment, when image formation is performed in a predetermined image forming mode set in advance, a plurality of sheets overlap on the optical path of the light beam L, and as a result, the sheet to the bin is discharged by the discharge sensor S33. When discharge cannot be detected, the image forming mode of the image forming unit is changed to avoid overlap of sheets on the optical path. Therefore, when the light beam L is shielded, there is always only one sheet on the optical path of the light beam L, and the sheet discharge to the bin can be reliably detected by the single discharge sensor S33.
[0059]
FIG. 8 is a flowchart showing another embodiment of the image forming apparatus according to the present invention. This embodiment is greatly different from the previous embodiment in the method of avoiding overlap when it is determined in step ST4 that a plurality of sheets are overlapped on the optical path of the light beam L. That is, in the previous embodiment, the image formation position is changed from the image formation position in the preset image formation mode to avoid the overlap of the sheets on the optical path. By changing the order of formation, paper overlap on the optical path is avoided.
[0060]
Next, the features of the present embodiment will be clarified with reference to specific examples of FIGS. 6 and 9. Again, in order to facilitate understanding of the contents of the embodiment, a case where an A4 size single-sided monochrome document is continuously discharged one by one into bin BIN1 located at the most downstream and bin BIN10 located at the most upstream. It is taken up. Of the two sheets that are continuously discharged back and forth, the bin from which the subsequent sheet is discharged is located on the downstream side in the common conveyance path with respect to the bin from which (C) the previous sheet is discharged. A specific example (FIG. 6) and (D) a specific example (FIG. 9) located on the upstream side of the common transport path from the bin where the first sheet is discharged will be described separately.
[0061]
<Specific example (C)>
In this specific example (C), similar to the specific example (A), an image formation command for requesting printing of the monochrome image I1 on A4 size paper and discharging it to the bin BIN10, and the monochrome image I2 in A4 size are provided. An image forming command is issued from the host computer 5 to the image forming apparatus 1 in this order as a print request for printing on paper and discharging to the bin BIN1.
[0062]
When continuous discharge to the multi-bin is requested in this way, in the image forming apparatus 1, the main controller 17 checks the discharge destination (bin number) of each sheet based on the print request contents (step ST3). Then, it is determined whether or not both of the two conditions (1) and (2) are satisfied. In this specific example (C), although the condition (2) is satisfied, the condition (1) Is not satisfied, it is determined that the plurality of sheets do not overlap on the optical path of the light beam L.
[0063]
Based on the determination result, the main controller 17 uses two image formation commands in a format suitable for the operation instruction of each part of the apparatus in order to perform image formation according to a preset image formation mode. More specifically, the image I1 and the image I2 are converted into job data for transferring to A4 size paper, respectively.
[0064]
Upon receiving this job data, the sub-controller 18 continuously forms images I1 and I2 corresponding to the respective documents on the intermediate transfer belt 41 in the order of print requests, as shown in FIG. 6B. Then, it is transferred and fixed to the respective sheets P (I1) and P (I2), and further conveyed to the multi-bin unit 3 (step ST6).
[0065]
For the papers P (I1) and P (I2) conveyed to the multi-bin unit 3, the papers P (I1) and P (P (I) on the optical path of the light beam L are similar to the specific example (A) described above. Since the sheets P (I1) and P (I2) are discharged to the corresponding bins without overlapping I2), the discharge sensor S33 can reliably detect the discharge of the sheets.
[0066]
Here, the case where the discharge destination of the previous paper P (I1) and the discharge destination of the subsequent paper P (I2) are illustrated is described as an example, but both discharge destinations are the same or close to each other Even in this case, the condition (1) is not always satisfied, and the discharge of the sheet can be reliably detected by the discharge sensor S33 in exactly the same manner as in the specific example (C).
[0067]
<Specific example (D)>
FIG. 9 is a diagram schematically illustrating the operation of the image forming apparatus and the multi-bin unit when the subsequent paper discharge destination is located upstream of the bin from which the previous paper is discharged in the common conveyance path. It is. In this specific example (D), as shown in FIG. 4A, an image formation command for requesting printing of monochrome image I1 on A4 size paper and discharging to bin BIN1, and monochrome image I2 for A4 An image forming command is issued from the host computer 5 to the image forming apparatus 1 in this order in order to print the size paper and discharge it to the bin BIN10.
[0068]
When continuous discharge to the multi-bin is requested in this way, in the image forming apparatus 1, the main controller 17 checks the discharge destination (bin number) of each sheet based on the print request contents (step ST3). Then, it is determined whether or not both of the above two conditions (1) and (2) are satisfied. In this specific example (D), both conditions (1) and (2) are satisfied, When an image is formed in a preset image forming manner as in the above specific example (C), it is determined that a plurality of sheets overlap on the optical path of the light beam L.
[0069]
Based on the determination result, the main controller 17 uses two image formation commands in a format suitable for the operation instructions of each part of the apparatus in order to avoid the overlap of sheets on the optical path. More specifically, images are formed in an order in which the order of print requests is reversed, and converted into job data for transferring them to A4 size paper.
[0070]
Upon receiving this job data, the sub controller 18 forms the images I2 and I1 on the intermediate transfer belt 41 in this order while forming the sheets P (I2) and P1 as shown in FIG. The image is transferred and fixed on (I1), and further conveyed to the multi-bin unit 3.
[0071]
An image I2 is formed on the paper P (I2) conveyed first to the multi-bin unit 3, and when this paper P (I2) is carried into the multi-bin unit 3, it is the same as in the specific example (A). Then, it is immediately discharged to the bin BIN10 located on the most upstream side. On the other hand, the paper P (I1) carried into the multi-bin unit 3 with a slight delay from the paper P (I2) is discharged to the bin BIN10 as shown in FIG. After that, it has moved along the common conveyance path 32, and after a further time has passed, the light L crosses the optical path for the first time and is discharged into the bin BIN1. Therefore, the sheets P (I1) and P (I2) are discharged to the corresponding bins without overlapping the sheets P (I1) and P (I2) on the optical path of the light beam L, and therefore reliably discharged by the discharge sensor S33. Paper discharge can be detected.
[0072]
In this embodiment, since the image forming mode is controlled by the image forming order, an excellent effect that is not found in the previous embodiment can be obtained. When controlling the image forming position as in the previous embodiment, if both of the conditions (1) and (2) are satisfied, the subsequent image forming position is set to the subsequent image in the preset image forming mode. Since the image interval is increased by changing to the rear side from the formation position, the throughput is reduced. On the other hand, in the present embodiment, only the image forming order is changed, and the image forming interval is not changed. Therefore, it is possible to prevent a decrease in throughput.
[0073]
The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above description, a case has been described in which two sheets of image-formed paper are continuously conveyed to the multi-bin unit 3 and discharged to different bins. However, three or more sheets are conveyed to the multi-bin unit 3. When the predetermined conditions (1) and (2) are satisfied in the same manner as described above, the image forming mode is changed to avoid the overlap of sheets on the optical path, and the single discharge sensor S33 is used. It is possible to reliably detect paper discharge. Further, the present invention can be applied not only when an image is formed on one side but also when an image is formed on both sides. For example, as shown in FIG. 10, the present invention can also be applied to a specific example (E) in which three-sided monochrome printing is performed.
[0074]
<Specific example (E)>
FIG. 10 is a diagram schematically illustrating operations of the image forming apparatus and the multi-bin unit when three sheets are sequentially discharged from the downstream bin to the upstream bin. In this specific example (E), as shown in FIG. 5A, a print request is made to print a monochrome double-sided image I1 (image I1F on the front side and image I1B on the back side) on A4 size paper and discharge it to bin BIN1 An image formation command that prints a monochrome double-sided image I2 (image I2F on the front side, image I2B on the back side) on A4 size paper and discharges it to bin BIN5, and A4 size paper An image forming command for printing a monochrome double-sided image I3 (image I3F on the front side and image I3B on the back side) and discharging it to the bin BIN10 is given in this order from the host computer 5 to the image forming apparatus 1. Yes.
[0075]
When continuous discharge to the multi-bin is requested in this way, in the image forming apparatus 1, the main controller 17 checks the discharge destination (bin number) of each sheet based on the print request contents (step ST3). Then, it is determined whether or not both of the two conditions (1) and (2) are satisfied. In this specific example (E), both conditions (1) and (2) are satisfied. When an image is formed in a preset image forming mode, it is determined that a plurality of sheets overlap on the optical path of the light beam L.
[0076]
Based on the determination result, the main controller 17 converts the three image formation commands into the following five job data in order to avoid the overlap of sheets on the optical path.
[0077]
(1) A job for printing the third back image I3B on the back surface of the paper P (I3);
(2) A job for printing the second and first back images I2B and I1B on the back of each of the sheets P (I2) and P (I1);
(3) A job for printing the third surface image I3F on the surface of the paper P (I3);
(4) A job for printing the second and first surface images I2F and I1F on the respective surfaces of the sheets P (I2) and P (I1);
Then, the sub-controller 18 that has received the job data forms the images I3 to I1 on the intermediate transfer belt 41 in this order, as shown in FIG. 5B, while the sheets P (I3) to P (I1). Then, the image is transferred and fixed to the multi-bin unit 3.
[0078]
A double-sided image I3 is formed on the paper P (I3) conveyed first to the multi-bin unit 3. When this paper P (I3) is carried into the multi-bin unit 3, a specific example (A) and Similarly, it is immediately discharged to the bin BIN10 located on the most upstream side. The paper P (I2) carried into the multibin unit 3 with a slight delay from the paper P (I3) is discharged to the bin BIN10 as shown in FIG. After that, it has moved along the common transport path 32, and after a further time has passed, the light L crosses the optical path for the first time and is discharged into the bin BIN5. Further, the sheet P (I1) carried into the multi-bin unit 3 with a slight delay from the sheet P (I2) follows the common conveyance path 32 even after the previous sheet P (I2) is discharged to the bin BIN5. After that, the light L crosses the optical path and is discharged to the bin BIN1. Accordingly, the sheets P (I1) to P (I3) are discharged to the corresponding bins without overlapping the sheets P (I1) to P (I3) on the optical path of the light beam L. Paper discharge can be detected.
[0079]
Instead of changing the image forming order by changing the image forming order, the image forming aspect may be changed by shifting the image forming position as shown in the specific example (B).
[0080]
In the above specific examples (A) to (E), the case where a monochrome image is formed on A4 size paper has been described. However, the application target of the present invention is not limited to monochrome printing, and is also applied to color printing. can do.
[0081]
In the above embodiment, the image forming system in which the image forming apparatus 1 and the multi-bin unit 3 are connected has been described. However, the present invention is also applied to an image forming system in which the multi-bin unit is incorporated in the image forming apparatus 1. The same effects as those of the above embodiment can be obtained by applying the present invention. Further, this image forming system may be configured such that the entire image forming system is controlled by the sub-controller without providing the multi-bin unit controller.
[0082]
In the above embodiment, the toner image on the photosensitive member 121 is transferred to the intermediate transfer belt 141. However, a transfer medium other than the intermediate transfer belt (transfer drum, transfer belt, transfer sheet, intermediate transfer drum, intermediate transfer sheet). The present invention can also be applied to an image forming apparatus that transfers a toner image to a reflective recording sheet or a transmissive storage sheet. The present invention can also be applied to an image forming apparatus that employs a so-called tandem system as an image forming system. The image forming apparatus 1 is a printer, and examples of the image forming apparatus include image forming apparatuses such as copying machines and facsimile machines. Furthermore, the present invention can also be applied to an image forming apparatus that forms an image by an image forming system other than the electrophotographic system, such as an ink jet system or a thermal transfer system.
[0083]
In the above embodiment, the intermediate transfer belt 141 is the image carrier of the present invention, and the image formation mode is controlled by changing the image formation position, the image formation order, and the like on the intermediate transfer belt 141. However, the image forming mode may be controlled by changing the image forming position or the image forming order on the photosensitive member 121. In particular, in an image forming apparatus that directly transfers an image on a photoconductor to a sheet without using an intermediate transfer medium, the image forming mode is controlled by changing the image forming position, interval, and forming order on the photoconductor. There is a need to.
[0084]
【The invention's effect】
As described above, according to the image forming apparatus and the image forming method of the present invention, when image formation is performed in a predetermined image forming mode set in advance, when a plurality of sheets overlap on the optical path of the light beam, the image forming means Since the image forming mode is changed so as to avoid the overlap of sheets on the optical path, when the light from the discharge sensor is blocked, one sheet is always on the optical path of the light. However, it is possible to reliably detect the discharge of the paper with a single discharge sensor for all the bins.
[0085]
Here, in order to avoid the overlap of the sheets on the optical path, it is possible to change the image forming mode by adjusting the image forming position, for example, but in this case, the interval between the images on the image carrier is widened. It may be disadvantageous in terms of throughput. On the other hand, when the image forming mode is changed by adjusting the image forming order, the processing can be performed with the same throughput as before the change of the image forming mode, which is preferable to the case where the image forming position is changed.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of an image forming system including an image forming apparatus according to the present invention.
2 is a diagram schematically showing a configuration of a multi-bin unit connected to an image forming apparatus in the image forming system of FIG.
FIG. 3 is a diagram illustrating an electrical configuration of the image forming system in FIG. 1;
4 is a diagram showing an electrical configuration of the multi-bin unit controller of FIG. 2; FIG.
FIG. 5 is a flowchart showing an embodiment of an image forming apparatus according to the present invention.
6 is a diagram schematically illustrating an image forming operation and a sheet discharging operation in a multi-bin unit executed according to the flowchart of FIG.
7 is a diagram schematically illustrating an image forming operation and a sheet discharging operation in a multi-bin unit executed according to the flowchart of FIG.
FIG. 8 is a flowchart showing another embodiment of the image forming apparatus according to the present invention.
9 is a diagram schematically showing an image forming operation and a sheet discharging operation in the multi-bin unit executed in accordance with the flowchart of FIG. 9. FIG.
10 is a diagram schematically showing an image forming operation and a sheet discharging operation in the multi-bin unit executed in accordance with the flowchart of FIG. 9. FIG.
FIG. 11 is a schematic diagram illustrating the operation of the proposed multi-bin unit.
[Explanation of symbols]
1. Image forming apparatus
3. Multi-bin unit
12 ... Photoconductor unit
13 ... Exposure unit
14 ... Transcription unit
16: Paper supply / discharge unit (conveying means)
17 ... Main controller (control means)
32 ... Common transport path
121: Photoconductor (image carrier)
141: Intermediate transfer belt (image carrier)
164 ... Paper discharge unit (conveying means)
L ... Ray
S33a: Projector
S33b ... Light receiving part
S33: Discharge sensor

Claims (8)

A plurality of bins that are branched from the common conveyance path at different branch positions, and the paper conveyed along the common conveyance path is selectively selected as one of the plurality of bins The paper is discharged from the common conveyance path to the bin based on transmission / shielding of the light beam while irradiating the plurality of bins with light beams in a skewered manner by discharge sensors provided in the vicinity of the plurality of branch positions. An image forming apparatus configured to be connectable to a multi-bin unit that detects discharge.
Image forming means for forming an image on paper;
A transport unit configured to transport the paper image formed by the image forming unit to the multi-bin unit;
Control means for controlling the image forming means,
When the control unit performs image formation in a predetermined image forming mode set in advance, when a plurality of sheets overlap on the optical path of the light beam, the control unit changes the image forming mode in the image forming unit on the optical path. An image forming apparatus characterized by avoiding overlapping of sheets. A plurality of bins that are branched from the common conveyance path at different branch positions, and the paper conveyed along the common conveyance path is selectively selected as one of the plurality of bins A multi-bin unit that discharges to
A discharge sensor for irradiating the plurality of bins with light beams in the vicinity of the plurality of branch positions and detecting discharge of paper from the common conveyance path to the bins based on transmission / shading of the light beams; ,
Image forming means for forming an image on paper;
A transport unit configured to transport the paper image formed by the image forming unit to the multi-bin unit;
Control means for controlling the image forming means,
When the control unit performs image formation in a predetermined image forming mode set in advance, when a plurality of sheets overlap on the optical path of the light beam, the control unit changes the image forming mode in the image forming unit on the optical path. An image forming apparatus characterized by avoiding overlapping of sheets. The control means has the following two conditions:
(1) Out of two sheets that are continuously discharged back and forth, the bin from which the subsequent sheet is discharged is positioned upstream of the bin from which the previous sheet is discharged in the common conveyance path. And the condition
(2) When a condition that the bin from which the preceding sheet is discharged and the bin from which the subsequent sheet is discharged is more than a predetermined interval is satisfied, The image forming apparatus according to claim 1, wherein the sheets are determined to overlap. The image forming means is configured to form an image to be formed on a sheet on an image carrier, and
The image forming apparatus according to claim 1, wherein the control unit controls an image forming mode by changing an image forming position on the image carrier. The image forming apparatus according to claim 4, wherein the image forming unit is configured to form an image corresponding to the image forming command on a photosensitive member functioning as the image carrier. The image forming means transfers a toner image corresponding to an image to be formed on a sheet on a photosensitive member and a toner image on the photosensitive member on an intermediate transfer medium functioning as the image carrier. The image forming apparatus according to claim 4, further comprising: a transfer unit that forms the image on the intermediate transfer medium. The image forming apparatus according to claim 1, wherein the control unit controls an image forming mode by changing an image forming order. A plurality of bins that are branched from the common conveyance path at different branch positions, and the paper conveyed along the common conveyance path is selectively selected as one of the plurality of bins The paper is discharged from the common conveyance path to the bin based on transmission / shielding of the light beam while irradiating the plurality of bins with light beams in a skewered manner by discharge sensors provided in the vicinity of the plurality of branch positions. An image forming method for conveying a sheet on which an image has been formed by an image forming unit with respect to a multi-bin unit that detects being discharged,
Determining whether or not a plurality of sheets overlap on the optical path of the light beam when performing image formation in a predetermined image forming mode set in advance;
An image forming method comprising: a step of changing an image forming mode in the image forming unit to avoid overlap of sheets on the optical path when it is determined that sheets overlap on the optical path.

Images