JP2020112726A - Image forming apparatus and method for controlling image forming apparatus - Google Patents

Abstract

To prevent a reduction in productivity of an image forming apparatus due to a delay in conveyance of a subsequent recording medium after execution of a re-image forming operation.SOLUTION: An image forming control unit comprises: a re-image formation control unit 209 that, when a conveyance delay occurs where a recording medium is not detected by a detection unit, after the lapse of a registration threshold time in which the time from when formation of a toner image is started by an image forming unit 1 until when conveyance of a recording medium is started so that the leading ends of the toner image and the recording medium match at a secondary transfer position, and within a time in which the time elapsed from when the conveyance of the recording medium is started by a conveying unit 72 is less than a jam threshold time, stops the formation of the toner image, and resumes the formation of the toner image with a second period different from the first period and in which the recording medium is detected as an image formation start period; and an image formation start period changing unit 210 that, after a re-image forming operation executed by the re-image formation control unit, changes the image formation start period in which formation of the toner image is started by the image forming unit to the second period.SELECTED DRAWING: Figure 3

Description

The present invention relates to an image forming apparatus and a control method for the image forming apparatus.

Conventionally, an electrophotographic image forming apparatus transfers a toner image formed on an image carrier or an intermediate transfer belt onto a recording medium that has been conveyed at a predetermined transfer timing.

In such an image forming apparatus, when it is determined that a conveyance delay occurs in which the conveyance of the recording medium is delayed with respect to the transfer timing, in order to suppress a decrease in productivity due to downtime of the image forming apparatus, a certain condition is set. The image formation of the toner image on the image carrier is stopped without interrupting the conveyance of the recording medium, and after the fact that the recording medium is conveyed to a predetermined position is detected, the image formation of the page is restarted. Reimage operation is known.

In addition, after executing the re-imaging operation, in order to suppress the decrease in productivity due to the conveyance delay of the subsequent recording medium, the print start operation is set to the operation mode of the image forming apparatus based on the prediction result of the conveyance delay of the recording medium. An apparatus is disclosed that selects either a print preceding type that is performed before the paper start operation or a paper feeding precedent type that is performed when the paper feed start operation is performed before the print start operation (for example, see Patent Document 1). ..

However, in the apparatus of Patent Document 1, after the re-imaging operation is performed, a conveyance delay occurs in the succeeding recording medium depending on the conveyance path of the recording medium or the type of the recording medium, and the image forming operation is performed again or the jam processing is performed. In some cases, the productivity of the image forming apparatus is reduced due to the necessity of performing the above.

The present invention has been made in view of the above points, and it is an object of the present invention to suppress a decrease in productivity of an image forming apparatus due to a conveyance delay of a subsequent recording medium after executing a reimage operation. To do.

An image forming apparatus according to an aspect of the disclosed technology is an image forming apparatus that forms an image on a recording medium, and an image carrier that conveys the recording medium and an image forming start time is a first time. An image forming unit for forming a toner image on the body, a primary transfer unit for primarily transferring the toner image to an intermediate transfer member, and a toner image primarily transferred on the intermediate transfer member for a predetermined secondary transfer position. A secondary transfer unit for secondary transfer to the recording medium, a detection unit for detecting the recording medium conveyed by the conveying unit, and an image forming control for controlling the formation of the toner image by the image forming unit. The image forming control unit starts the image formation of the toner image by the image forming unit, and the toner image and the recording medium are aligned so that their leading ends are aligned at the secondary transfer position. The time until the start of the conveyance of the recording medium is equal to or longer than a predetermined registration threshold time, and the elapsed time from the time when the conveyance of the recording medium is started by the conveyance unit is less than a jam threshold time. When the conveyance delay occurs in which the recording medium is not detected by the detection unit, the image formation of the toner image is stopped, and a second time different from the first time when the recording medium is detected is set. As an image formation start time, after the re-imaging control unit that restarts the formation of the toner image and the re-imaging operation by the re-imaging control unit are executed, the image formation unit starts the formation of the toner image. And an image forming start time changing unit for changing the image forming start time to the second time.

According to the embodiments of the present invention, it is possible to suppress a decrease in productivity of the image forming apparatus, which is caused by a conveyance delay of a subsequent recording medium after executing the re-imaging operation.

FIG. 1 is a diagram illustrating an example of a configuration of an image forming apparatus according to an exemplary embodiment. 3 is a block diagram illustrating an example of a hardware configuration of a control unit of the image forming apparatus according to the exemplary embodiment. FIG. 3 is a block diagram illustrating an example of a functional configuration of a control unit of the image forming apparatus according to the first exemplary embodiment. FIG. 6 is a flowchart showing an example of a reimage operation by the image forming apparatus according to the first embodiment. 6 is a flowchart illustrating an example of an image forming operation of a succeeding sheet after the image forming operation is performed by the image forming apparatus according to the first exemplary embodiment. FIG. 9 is a diagram illustrating an example of a situation where a conveyance delay occurs in a print request. FIG. 9 is a block diagram illustrating an example of a functional configuration of a control unit of the image forming apparatus according to the second exemplary embodiment. 9 is a flowchart illustrating an example of an image forming operation of a succeeding sheet after the image forming operation is performed by the image forming apparatus according to the second exemplary embodiment. FIG. 11 is a block diagram illustrating an example of a functional configuration of an image forming apparatus according to a modified example of the second embodiment. 9 is a flowchart showing an example of an image forming operation of a succeeding sheet after the image forming operation is executed by the image forming apparatus according to the modified example of the second exemplary embodiment. It is a figure which shows an example of the notification which a display part displays. 9 is a block diagram illustrating an example of a functional configuration of a control unit of the image forming apparatus according to the third exemplary embodiment. FIG. 9 is a flowchart illustrating an example of an image forming operation of a succeeding sheet after the image forming operation is performed by the image forming apparatus according to the third exemplary embodiment. It is a block diagram explaining an example of functional composition of a control part of an image forming device concerning a 4th embodiment.

Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In each drawing, the same reference numerals are given to the same components, and duplicate description may be omitted.

The recording medium in the embodiment is paper, a plastic sheet, or the like. Hereinafter, a case where the recording medium is a sheet will be described as an example. In addition, image forming, printing, and printing in the terms of the embodiments are synonymous.

<Configuration of Image Forming Apparatus According to Embodiment>
An image forming apparatus according to an embodiment will be described with reference to the drawings by taking an electrophotographic image forming apparatus using an intermediate transfer belt called a tandem type as an example.

FIG. 1 is a diagram illustrating an example of the configuration of the image forming apparatus according to the embodiment. As shown in FIG. 1, inside the image forming apparatus 100, four images are formed in order to form images of cyan (C), magenta (M), yellow (Y), and black (K). The units 1C, 1M, 1Y, and 1K (hereinafter referred to as the image forming unit 1 when not distinguished, the same applies to other components). The image forming units 1 have almost the same configuration except that the toner colors are different.

The image forming units 1 each include a drum-shaped image carrier 2. The four image carriers 2 are arranged in parallel inside the image forming apparatus 100 at equal intervals in the moving direction of the intermediate transfer belt 16. Here, the intermediate transfer belt 16 is an example of an “intermediate transfer member”. When the driving force is transmitted from a driving source such as a motor, each of the image carriers 2 has its peripheral surface rotated in the same direction as the conveying direction of the intermediate transfer belt 16 which faces the image carrier 2.

A toner image is formed on the image carrier 2 by an image forming process using laser light inside the image forming unit 1. A transfer unit 15 is provided below the image carrier 2. The transfer section 15 has an endless intermediate transfer belt 16, one end of which is wound around a driven roller 17 and the other end of which is wound around a transfer driving roller 18.

Then, the transfer driving roller 18 driven by the drive source rotates, so that the intermediate transfer belt 16 runs in the direction of arrow A, and the surface of each image carrier 2 comes into contact with the upper surface of the intermediate transfer belt 16. ing. Four primary transfer rollers 19 are provided on the inner peripheral portion of the intermediate transfer belt 16 so as to face each image carrier 2. Here, the primary transfer roller 19 is an example of a “primary transfer portion”.

A belt cleaning unit 21 having a toner image removing function is provided on the outer peripheral portion near the right end portion of the intermediate transfer belt 16. The belt cleaning unit 21 can wipe off unnecessary toner remaining on the surface of the intermediate transfer belt 16 and foreign matter such as paper dust.

On the outer periphery of the intermediate transfer belt 16, a secondary transfer roller 20 that constitutes the transfer unit 15 is provided at a position facing the transfer driving roller 18 with the intermediate transfer belt 16 interposed therebetween. The secondary transfer roller 20 is in contact with the intermediate transfer belt 16 at a position (an example of “secondary transfer position”) facing the transfer driving roller 18 to form a secondary transfer nip. Here, the secondary transfer roller 20 is an example of a “secondary transfer section”.

In the secondary transfer nip, the sheet P, which is a recording medium, passes between the intermediate transfer belt 16 and the secondary transfer roller 20, and a bias is applied to the toner that is imaged and carried on the intermediate transfer belt 16. The image is electrostatically transferred to the paper P.

The paper feed tray 30 accommodates a plurality of sheets P stacked in the internal space thereof. A bottom plate 46 for mounting the sheets P in a stacked state is provided on the bottom surface of the internal space of the paper feed tray 30. One end of the bottom plate 46 in the longitudinal direction is rotatably supported by a support shaft, and the other end of the bottom plate 46 is vertically swingable. The bottom plate 46 is constantly urged upward by a biasing member such as a spring.

A paper feed roller 47 as a rotating member is provided on the paper feed tray 30 on the end side where the bottom plate 46 swings. The paper feed roller 47 comes into contact with the uppermost part of the bundle of papers P placed on the paper feed tray 30 in a stacked state, and the uppermost paper P can be fed out.

The paper feed roller 47 need not be in the form of a roller, as long as it can convey the paper P in a predetermined direction. For example, instead of the paper feed roller 47, an endless rotary belt that spans between two rollers may be used.

A registration sensor 31 (an example of a detection unit) capable of detecting the leading edge of the paper P is provided downstream of the paper feed roller 47 in the transport direction. A registration roller pair 32, which is a medium standby unit that temporarily stops the paper P, is provided downstream of the registration sensor 31 in the transport direction.

The registration roller pair 32 is arranged immediately upstream of the intermediate transfer belt 16 and temporarily stops the paper P in order to accurately align the toner image carried on the intermediate transfer belt 16 and the leading end position of the paper at the transfer portion. To loosen temporarily. The registration roller pair 32 causes the toner image, which is formed and carried on the intermediate transfer belt 16, to be transferred to the paper P at the secondary transfer nip portion immediately before the toner image is transferred to the paper P. To send to the secondary transfer nip. That is, the registration of the secondary transfer nip portion of the paper P is restarted. The sheet feeding tray 30, the sheet feeding roller 47, the pair of registration rollers 32, and the like form a conveying unit 72.

A fixing unit 34 is provided further downstream in the transport direction than the secondary transfer nip portion formed by the secondary transfer roller 20 and the transfer driving roller 18. The fixing unit 34 includes a fixing roller 34a that includes a heat source such as a halogen lamp, and a pressure roller 34b that rotates while contacting the fixing roller 34a with a predetermined pressure. The fixing unit 34 may have an endless rotary belt or may have another structure such as an IH heating system.

<Operation of Image Forming Apparatus According to Embodiment>
Next, the operation of the image forming apparatus 100 will be described. In FIG. 1, when the paper feed roller 47 of the paper feed tray 30 is rotated by a conveyance start signal from the control unit of the image forming apparatus 100, the paper P at the top of the paper P stacked on the bottom plate 46 of the paper feed tray 30. Only the sheet P is sent out separately from the sheet P below the sheet P.

When the leading edge of the sheet P is detected by the registration sensor 31, the sheet P is fed until the predetermined slack is formed at the secondary transfer nip portion of the registration roller pair 32, triggered by the detected timing, and the leading edge of the sheet P is detected. Skew is corrected.

Next, the image forming operation of the image forming apparatus 100 will be described. The toner image formed on the image carrier 2K is primary-transferred to the surface of the intermediate transfer belt 16 that moves in synchronization with the image carrier 2K by the transfer action of the positively-charged primary transfer roller 19K. It The latent image formation, development, and primary transfer operations by the image forming units 1 are sequentially performed at timings corresponding to the image data in all the image forming units 1, and the operations are performed on the surface of the intermediate transfer belt 16. , Cyan C, magenta M, yellow Y, and black K toner images of four colors are sequentially carried. Here, the start timing of forming the toner image by the image forming unit 1 corresponding to the above-mentioned image data is predetermined according to the image forming speed, productivity, etc., and does not depend on the position of the paper P. Is the timing to start the, and is an example of the “first time”. More specifically, among the operations for forming the toner image by the image forming unit 1, the start timing of the earliest image formation corresponds to the “first time”. When the image forming start timings of the four image forming units 1 are different, the earliest one corresponds to the “first time period”.

The four-color toner image on the intermediate transfer belt 16 is conveyed together with the intermediate transfer belt 16 that moves on the surface in the direction of arrow A. When the toner images of the respective colors are transferred to the intermediate transfer belt 16, the registration roller pair 32 and the paper feed roller 47 start driving, and the paper P is transferred so that the timings of the toner images transferred to the intermediate transfer belt 16 match. It is conveyed toward the secondary transfer roller 20, which is the position. The registration roller pair 32 and the paper feed roller 47 do not have to start driving at the same time.

Further, in addition to the registration roller pair 32 and the paper feed roller 47, there may be a transport roller for transporting the paper P. The secondary transfer roller 20 is positively charged, and the toner image on the intermediate transfer belt 16 is transferred onto the fed paper P by the secondary transfer nip portion of the secondary transfer roller 20.

Residual toner and foreign matter on the surface of the intermediate transfer belt 16 are removed by the belt cleaning unit 21 for the next image forming/transferring process. The sheet P to which the toner image is transferred is transferred to the fixing unit 34 after being transferred. The sheet P sent to the fixing unit 34 is sandwiched between the fixing roller 34a and the pressure roller 34b, and the unfixed toner image is heated and pressed to be fixed on the sheet P.

<Hardware Configuration of Image Forming Apparatus According to Embodiment>
Next, the hardware configuration of the control unit of the image forming apparatus according to the embodiment will be described with reference to FIG.

FIG. 2 is a block diagram illustrating an example of the hardware configuration of the control unit of the image forming apparatus according to the embodiment. As shown in FIG. 2, the control unit 200 included in the image forming apparatus 100 includes a UART (Universal Asynchronous Receiver Transmitter) 57, a CPU (Central Processing Unit) 58, a ROM (Read Only Memory) 59, and a RAM (Random Access). Memory) 60, NVRAM (Non-volatile Random Access Memory) 61, operation panel I/F (Inter/Face) 62, I/O (Input/Output) 65, and image processing IC (Integrated Circuit) 66. Have. Each is mutually connected via the system bus 64. The ROM 59, the RAM 60, and the NVRAM 61 configure a storage unit of the image forming apparatus 100 according to the embodiment.

An operation panel 63 operated by a user is connected to the operation panel I/F 62, and a controller 67 is connected to the image processing IC 66. The I/O 65 includes a registration sensor 31 that detects that the paper P is being conveyed, a conveyance motor 69 that rotationally drives the paper feed roller 47, a transfer motor 70 that rotationally drives the transfer drive roller 18, and a transfer motor 70. The photoconductor motors 71 that rotate and drive the image carrier 2 are connected to each other.

An operation panel 63 is connected to the CPU 58 via an operation panel I/F 62. The operation panel 63 includes a display unit and an input unit, functions as a user interface, and is used for setting an image forming mode of the image forming apparatus.

The operation panel I/F 62 exchanges data between the CPU 58 and the operation panel 63. A controller 67 is connected to the CPU 58 via an image processing IC 66. The CPU 58 acquires printing conditions such as the thickness of the printing paper from the controller 67.

The CPU 58 controls the image forming apparatus 100 according to the embodiment, and generally controls access to various devices connected to the system bus 64 based on a control program stored in the ROM 59. The CPU 58 controls input/output of the registration sensor 31, the conveyance motor 69, the transfer motor 70, and the photoconductor motor 71 which are connected via the I/O 65. That is, the CPU 58 executes the control program of the image forming apparatus 100 stored in the ROM 59.

The CPU 58 performs image forming operations such as measurement of the conveyance time of the paper P, detection of conveyance time delay, re-imaging, re-registration (re-conveyance), etc. according to an instruction composed of a control program, control data, and the like. Perform such control.

The ROM 59 is a read-only non-volatile memory, and stores a control program used by the CPU 58, control data, and the like.

The RAM 60 is a volatile memory capable of reading and writing information at high speed, and is used as a work frame memory used for expanding recording data and storing environmental data.

The NVRAM 61 is a readable/writable non-volatile memory, and stores information regarding the image forming apparatus used by the control program. The UART 57 is an integrated circuit that converts a signal for serial communication and a signal for parallel communication.

<Functional Configuration of Image Forming Apparatus According to First Embodiment>
Next, the functional configuration of the control unit 200 included in the image forming apparatus 100 according to the first embodiment will be described with reference to FIG. FIG. 3 is a block diagram illustrating an example of the functional configuration of the control unit of the image forming apparatus. All or some of the functional blocks shown in FIG. 3 may be functionally or physically dispersed or combined in arbitrary units.

As shown in FIG. 3, the control unit 200 includes an I/F unit 201, a conveyance control unit 202, an image forming control unit 203, a transfer control unit 204, a fixing control unit 205, a monitoring unit 206, and an operation unit. And part 207.

The I/F unit 201 communicates with a terminal device that requests the image forming apparatus 100 to form an image. The I/F unit 201 transmits the image data transmitted from the terminal device to the image forming control unit 203 and the like, and requests the image forming apparatus 100 to form an image.

The conveyance control unit 202 is electrically connected to the conveyance motor 69, controls the rotation of the conveyance motor 69, and conveys the toner image on the intermediate transfer belt 16 to the paper P at the secondary transfer nip portion. The timing at which the section 72 conveys the paper P is controlled.

The image forming control unit 203 is electrically connected to the image forming unit 1, controls the image forming unit 1 to execute an image forming process, and forms a toner image of each color on the image carrier 2 of each color. You can Further, the image forming control unit 203 includes an image writing control unit 208, a reimage forming control unit 209, an image forming start timing changing unit 210, and a time determination unit 211.

The image writing control unit 208 converts the image data transmitted from the I/F unit 201 into control signals for each color included in the image forming unit 1, and writes a latent image on the image carrier 2 using laser light. To control.

Here, after the image forming unit 1 starts forming a toner image of a predetermined page based on the image data, the conveyance of the paper by the registration rollers is started so that the leading edge of the image and the paper are aligned at the secondary transfer position. The time until the registration is restarted is defined as the registration restart time, and the elapsed time from when the transport unit 72 starts transporting the paper P is defined as the jam determination time. The re-imaging control unit 209 does not detect the leading edge of the sheet P by the registration sensor 31 within a time period in which the registration restart time is equal to or longer than the predetermined registration threshold time and the jam determination time is shorter than the predetermined jam threshold time. When a conveyance delay (hereinafter, simply referred to as a conveyance delay) occurs, the image forming unit 1 stops the toner image formation. Then, the image forming unit 1 resumes the formation of the toner image of the stopped predetermined page so that the leading edge of the paper P becomes later than the timing detected by the registration sensor 31. The reason why the leading edge of the paper P is “delayed” from the timing detected by the registration sensor 31 is that the image formation is caused by the waiting time until the fixing unit 34 becomes ready for fixing or other adjustment operation. This is because there is a possibility that there will be a time when it will not be possible. The re-imaging control unit 209 has a function of executing the re-imaging operation as described above.

The timing at which the leading edge of the paper P is detected by the registration sensor 31 is the timing at which image formation is started based on the position of the paper P, and is an example of the “second time”.

The image forming start timing changing unit 210 determines the timing when the image forming unit 1 starts forming the toner image after the image forming control unit 209 executes the image forming operation, by the registration sensor 31 at the leading edge of the paper P. It has the function of changing to the detected timing. That is, the image forming start time changing unit 210 can change the image forming start time, which is the time when the toner image is formed, from the first time to the second time.

The time determination unit 211 measures the resist restart time and determines whether the resist restart time is equal to or longer than the resist threshold time. The time determination unit 211 also measures the jam determination time and determines whether the jam determination time is less than the jam threshold value. The time determination unit 211 can measure the time by counting the clocks used for the operation of the CPU 58.

The transfer control unit 204 is electrically connected to the transfer unit 15 and controls the transfer unit 15 to primarily transfer the toner image formed on the image carrier 2 to the intermediate transfer belt 16 and to transfer the toner image on the intermediate transfer belt 16. The toner image is secondarily transferred to the paper P. In addition, the transfer control unit 204 can primarily transfer the toner image formed on the image carrier 2 to the intermediate transfer belt 16 when the re-imaging control unit 209 executes the re-imaging operation.

The fixing control unit 205 is electrically connected to the fixing unit 34, and controls the fixing unit 34 to heat and press the unfixed toner image formed on the paper P to fix it on the paper P.

The monitoring unit 206 is electrically connected to the registration sensor 31, monitors the state of the registration sensor 31, and can determine the timing when the leading edge of the paper P is detected by the registration sensor 31. Although the registration sensor 31 is illustrated in the present embodiment, any sensor may be arranged at any position as long as the timing at which the leading edge of the paper P is detected by the registration sensor 31 can be determined.

The operation unit 207 is electrically connected to the operation panel 63, can display the state of the image forming apparatus 100 via the operation panel 63, and can accept an input to the image forming apparatus 100.

<Operation of Image Forming Apparatus According to First Embodiment>
Next, the operation of the image forming apparatus according to the first embodiment will be described.

FIG. 4 is a flowchart showing an example of the re-imaging operation by the image forming apparatus according to this embodiment.

First, in step S41, the image forming unit 1 starts forming a toner image under the control of the image forming control unit 203.

Then, in step S42, the time determination unit 211 starts measuring the registration restart time.

Subsequently, in step S43, the transport unit 72 starts transporting the paper P under the control of the transport control unit 202.

Subsequently, in step S44, the time determination unit 211 starts measuring the jam determination time.

Subsequently, in step S45, the monitoring unit 206 determines whether the registration sensor 31 has detected the leading edge of the paper P.

When it is determined in step S45 that the registration sensor 31 has detected the leading edge of the paper P (step S45, Yes), the transport unit 72 controls the secondary transfer nip portion under control of the transport control unit 202 in step S46. The paper P is conveyed to. That is, the registration of the paper P is restarted.

Subsequently, in step S47, the transfer unit 15 secondarily transfers the toner image on the intermediate transfer belt 16 to the paper P at the secondary transfer nip portion under the control of the transfer control unit 204.

Subsequently, in step S48, the fixing unit 34 fixes the unfixed toner image on the paper P to the paper P under the control of the fixing control unit 205.

Subsequently, in step S49, the transport unit 72, under the control of the transport control unit 202, discharges the paper P on which the toner image is fixed to a discharge tray or the like outside the image forming apparatus.

On the other hand, when it is determined in step S45 that the registration sensor 31 does not detect the leading edge of the sheet P (step S45, No), the time determination unit 211 determines in step S50 whether the jam determination time is less than the jam threshold time. Determine whether.

When it is determined in step S50 that the time is not less than the jam threshold time (step S50, No), the control unit 200 causes the image forming apparatus 100 to interrupt the image forming operation in step S51.

On the other hand, when it is determined in step S50 that the time is less than the jam threshold time (step S50, Yes), in step S52, the time determination unit 211 determines whether the registration restart time is equal to or longer than the registration threshold time.

When it is determined in step S52 that it is not longer than the registration threshold time (step S52, No), the process returns to step S45, and step S45 and subsequent steps are repeated. On the other hand, when it is determined in step S52 that the time is equal to or longer than the registration threshold time (step S52, Yes), the image forming unit 1 forms a toner image under the control of the image forming control unit 209 in step S53. Discontinue.

Subsequently, in step S54, the monitoring unit 206 determines whether the registration sensor 31 has detected the leading edge of the paper P.

When it is determined in step S54 that the registration sensor 31 does not detect the leading edge of the paper P (step S54, No), the time determination unit 211 determines in step S55 whether the jam determination time is less than the jam threshold time. judge.

When it is determined in step S55 that the time is not less than the jam threshold time (step S55, No), the control unit 200 causes the image forming apparatus 100 to suspend the image forming operation. On the other hand, when it is determined that the time is less than the jam threshold time (Yes in step S55), the process returns to step S53, and step S53 and subsequent steps are repeated.

On the other hand, when it is determined in step S54 that the registration sensor 31 has detected the leading edge of the paper P (Yes in step S54), the image forming unit 1 is controlled by the re-image forming control unit 209 in step S57. Resume the stopped toner image formation. More specifically, the cleaning unit (not shown) of the image carrier 2 removes the toner image formed on the image carrier 2, and the toner image formed halfway on the intermediate transfer belt 16 is cleaned by the belt cleaning unit. 21 is removed, and the image forming unit 1 performs each operation for forming the stopped toner image again from the beginning. Then, the process proceeds to step S46, and steps S46 and thereafter are executed.

In this way, the re-imaging operation can be executed when a conveyance delay occurs in which the paper P is not detected by the registration sensor 31 during a time that is equal to or greater than the predetermined registration time threshold and less than the jam threshold time.

Next, FIG. 5 is a flowchart showing an example of the image forming operation of the succeeding sheet after the image forming operation is executed by the image forming apparatus according to the present embodiment.

After executing the re-imaging operation, first, in step S51, the image formation start time changing unit 210 changes the image formation start time from the first time to the second time.

Subsequently, in step S52, the transport unit 72 continues to transport the paper P under the control of the transport control unit 202.

Then, in step S53, the time determination unit 211 starts measuring the jam determination time.

Subsequently, in step S54, the monitoring unit 206 determines whether the registration sensor 31 has detected the leading edge of the paper P.

When it is determined in step S54 that the registration sensor 31 has detected the leading edge of the sheet P (step S54, Yes), the image forming unit 1 forms a toner image under the control of the image forming control unit 203 in step S55. Start.

Subsequently, in step S56, the transport unit 72 restarts the registration of the paper P under the control of the transport control unit 202.

Subsequently, in step S57, the transfer unit 15 secondarily transfers the toner image on the intermediate transfer belt 16 to the sheet P at the secondary transfer nip portion under the control of the transfer control unit 204.

Subsequently, in step S58, the fixing unit 34 fixes the unfixed toner image on the paper P to the paper P under the control of the fixing control unit 205.

Subsequently, in step S59, the transport unit 72, under the control of the transport control unit 202, discharges the sheet P on which the toner image has been fixed onto a discharge tray or the like outside the image forming apparatus.

On the other hand, when it is determined in step S54 that the registration sensor 31 does not detect the leading edge of the paper P (step S54, No), the time determination unit 211 determines in step S60 whether the jam determination time is less than the jam threshold time. Determine whether.

When it is determined in step S60 that the time is not less than the jam threshold time (step S60, No), the control unit 200 causes the image forming apparatus 100 to interrupt the image forming operation in step S61.

On the other hand, when it is determined in step S60 that the time is less than the jam threshold time (step S60, No), the process returns to step S54, and step S54 and subsequent steps are repeated.

In this way, it is possible to change the image formation start time to the second time and execute the image formation of the succeeding sheet after the re-imaging operation.

<Effect>
A plurality of transport rollers including a paper feed roller 47 and a registration roller pair 32 are used to transport the paper P from the paper feed tray to the secondary transfer nip portion. If the sheet P is present, slippage occurs between the conveying roller and the sheet P, so that the sheet P cannot be conveyed in time at the secondary transfer timing, and a jam error is likely to occur.

When a jam error occurs, the user needs to perform a jam clearance operation for removing the paper P from the image forming apparatus 100, and downtime of the image forming apparatus 100 may reduce productivity.

In the present embodiment, the toner image re-forming operation described above is executed to suppress a jam error, and downtime of the image forming apparatus 100 for clearing the jam is reduced, thereby suppressing a decrease in productivity. it can.

Further, depending on the conveyance path of the recording medium such as the paper P or the type of the recording medium, slippage is likely to occur between the conveyance roller and the paper P, and after the re-imaging operation is performed, the conveyance delay also occurs in the succeeding recording medium. May occur.

In the present embodiment, after the toner image re-imaging operation is executed, the image formation start time is set so that the toner image formation is started at the second time when the registration sensor 31 detects the leading edge of the paper P. The changing unit 210 changes the image formation start time. Since the toner image formation is not started until the registration sensor 31 detects the leading edge of the paper P, even if a conveyance delay occurs in the succeeding paper due to the slip between the conveyance roller and the paper P, a jam error does not occur, The downtime of the image forming apparatus 100 can be reduced.

[Second Embodiment]
Next, an image forming apparatus according to the second embodiment will be described. Note that the description of the same components as those of the above-described embodiment will be omitted.

First, FIG. 6 is a diagram illustrating an example of a situation in which a conveyance delay occurs in a print request. In FIG. 6, the horizontal axis represents time. In FIG. 6, a print request is transmitted from the terminal device to the control unit of the image forming apparatus, and among the image data of four pages included in the print request, when the image forming of the second page surrounded by the broken line circle 81 is performed, the paper This indicates that a conveyance delay has occurred. Here, the “print request” refers to a print group recognized by the control unit of the image forming apparatus and continuously printed. This "print request" is different from a general "print job". For example, when the user A sends a print job for printing two sheets to the image forming apparatus and the user B sends a print job for printing three sheets to the image forming apparatus, and when five sheets are continuously printed, The control unit of the image forming apparatus recognizes the "print request" as a print group including five prints. Further, when the user sends a print job for printing 100 sheets to the image forming apparatus, if the 31st sheet and the 32nd sheet are not available and continuous printing is not performed due to communication delay of the Internet, etc. The control unit recognizes two "print requests", that is, "print request" for printing 31 sheets and "print request" for printing 69 sheets.

In the image forming apparatus 100a according to the present embodiment, the re-imaging operation is executed in the image formation of the second page in which the sheet conveyance delay has occurred. Then, after the image formation start time of the subsequent 3rd to 4th pages is changed to the second time and the toner image is formed, that is, after the print request is completed, the image formation start time is set to the first time. It is characterized by returning to.

FIG. 7 is a diagram illustrating an example of the functional configuration of the control unit of the image forming apparatus according to the present exemplary embodiment. The control unit 200a of the image forming apparatus 100a has an image forming control unit 203a, and the image forming control unit 203a has an image forming start timing changing unit 210a. Further, the image formation start time changing unit 210a has a print request end determination unit 212.

The print request end determination unit 212 counts the number of sheets of paper on which an image is formed and compares the count with the number of pages of the image data included in the print request, so that the print request for the image started when the conveyance delay occurs. Can be determined whether or not all have been completed.

The image forming start time changing unit 210a changes the image forming start time to the second time when the conveyance delay of the paper P occurs. Then, when the print request end determination unit 212 determines that the print request is completed after the image formation is performed on the succeeding sheet with the second time as the image formation start time, the image formation start time is set to the first image formation start time. Can be changed at any time.

FIG. 8 is a flowchart showing an example of the image forming operation of the succeeding sheet after the image forming operation is executed by the image forming apparatus according to the present embodiment.

Steps S81 to S89 are the same as steps S51 to S59 in FIG. 5, and steps S92 and S93 are the same as steps S60 and S61 in FIG. 5, so description thereof will be omitted.

In step S90, the print request end determination unit 212 determines whether the print request has ended.

When it is determined in step S90 that the print request is completed (step S90, Yes), the image forming start timing changing unit 210a changes the image forming start timing from the second timing to the first timing in step S91. change. On the other hand, if it is determined in step S90 that the print request has not ended (No in step S90), the process returns to step S82, and steps S82 and subsequent steps are repeated.

In this way, after the image formation start time is changed to the second time, when all the image print requests that were started when the conveyance delay occurred, the image formation start time is changed to the first time. can do.

In one print request, the image of each page is formed on the same type of paper. Therefore, if there is a page in which a paper conveyance delay occurs in the print request, the conveyance delay will be similarly applied to other pages. May occur. In the present embodiment, when a sheet conveyance delay occurs, image formation is performed with the image formation start time as the second timing, and after all the image print requests that were started when the conveyance delay occurred, The image formation start time is returned to the first time. Thus, during the execution of the print request, the image formation is performed with the second timing as the image formation start time, so that the conveyance delay can be surely prevented in the succeeding paper after the re-imaging operation.

The effects other than those described above are the same as those described in the first embodiment.

<Modification>
FIG. 9 is a diagram illustrating an example of a functional configuration of the image forming apparatus according to the modified example of the second embodiment. The control unit 200b of the image forming apparatus 100b includes an image forming control unit 203b, and the image forming control unit 203b includes an image forming start timing changing unit 210b. The image formation start time changing unit 210b has a number-of-times determining unit 213, and the operation panel 63b has a display unit 631.

The number-of-times determining unit 213 can determine whether the number of occurrences of the conveyance delay is equal to or greater than a predetermined number, and whether all the image print requests started when the conveyance delay occurs are completed. it can. The number-of-times determination unit 213 also outputs the determination result to the notification display control unit 214.

The image forming start time changing unit 210b changes the image forming start time to the second time when the conveyance delay of the paper P occurs. Further, the image forming start time changing unit 210b is configured to change the image forming start time to the second time, and when the number of occurrences of the conveyance delay is equal to or more than a predetermined number of times and the print request is completed. The image formation start time can be changed to the first time.

The display unit 631 displays a notification such as a warning based on the determination result input from the frequency determination unit 213 via the operation unit 207.

FIG. 10 is a flowchart showing an example of the image forming operation of the succeeding sheet after the image forming operation is executed by the image forming apparatus according to the present embodiment.

Steps S101 to S109 are the same as steps S51 to S59 in FIG. 5, and S113 and S114 are the same as steps S60 and S61 in FIG. 5, so description thereof will be omitted.

In step S110, the number-of-times determination unit 213 determines whether or not the number of occurrences of the conveyance delay is equal to or greater than a predetermined number, and whether all the image print requests started when the conveyance delay occurs are completed. judge.

If it is determined in step S110 that the number of times of occurrence of the conveyance delay is equal to or greater than a predetermined number of times and all the print requests for the image started when the conveyance delay occurs (step S110, Yes) In step S111, the image forming start time changing unit 210b changes the image forming start time from the second time to the first time.

Subsequently, in step S112, the display unit 631 displays a notification such as a warning based on the determination result input from the frequency determination unit 213 via the operation unit 207. Here, FIG. 11 is a diagram illustrating an example of the notification displayed by the display unit 631.

Returning to FIG. 10, if it is determined in step S110 that the print request is not completed (No in step S110), the process returns to step S102, and step S102 and subsequent steps are repeated.

In this way, after the image formation start time is changed to the second time, the number of occurrences of the conveyance delay is equal to or greater than a predetermined number of times, and the printing of the image started when the conveyance delay occurs When all the requests are completed, the image formation start time can be changed to the first time.

In one print request, the image of each page is formed on the same type of paper. Therefore, if there is a page in which a paper conveyance delay occurs in the print request, the conveyance delay will be similarly applied to other pages. May occur. Further, when the number of occurrences of the conveyance delay becomes larger than the predetermined number, the possibility of causing the conveyance delay also increases in other pages.

In the present embodiment, when a sheet conveyance delay occurs, image formation is performed with the image formation start timing as the second timing, the number of conveyance delay occurrences is equal to or greater than a predetermined number, and the conveyance delay occurs. When all the image print requests that have been started at the end are completed, the image formation start time is returned to the first time. Thus, during the execution of the print request, the image formation is performed with the second timing as the image formation start timing, so that the conveyance delay can be reliably prevented in the succeeding paper after the paper conveyance delay occurs.

Further, it is possible to notify the user that slippage has occurred between the transport roller and the paper, and to give an opportunity to review the paper.

The effects other than those described above are the same as those already described.

[Third Embodiment]
Next, an image forming apparatus according to the third exemplary embodiment will be described.

FIG. 12 is a diagram illustrating an example of the functional configuration of the control unit of the image forming apparatus according to the third embodiment. The control unit 200c of the image forming apparatus 100c includes an image forming control unit 203c and a number setting unit 113, and the image forming control unit 203c includes an image forming start timing changing unit 210c. Further, the image formation start timing changing unit 210c has a number-of-sheets determining unit 215.

The number-of-sheets determination unit 215 can determine whether or not a predetermined number of images have been formed. Further, the number-of-sheets setting unit 113 can output a predetermined number of pieces of data input via the operation panel 63 or the like to the number-of-sheets determination unit 215. The number determination unit 215 can use the input number data as predetermined number data.

The image forming start time changing unit 210c changes the image forming start time to the second time when the conveyance delay of the paper P occurs. Further, the image forming start time changing unit 210c can change the image forming start time to the first time when a predetermined number of images are formed after changing the image forming start time to the second time. ..

FIG. 13 is a flowchart showing an example of the image forming operation of the succeeding sheet after the image forming operation is executed by the image forming apparatus according to the present embodiment.

Steps S131 to S139 are the same as steps S51 to S59 in FIG. 5, and S142 and S143 are the same as steps S60 and S61 in FIG. 5, so description thereof will be omitted.

In step S140, the number determination unit 215 determines whether or not a predetermined number of images have been formed.

When it is determined in step S140 that the predetermined number of images have been formed (Yes in step S140), in step S141, the image formation start timing changing unit 210c sets the image formation start timing to the second timing. From the first time.

In this way, when the predetermined number of images are formed after the image formation start time is changed to the second time, the image formation start time can be changed to the first time.

In the case of paper with a large amount of slippage, if the image formation start time is immediately returned to the first time, there is a possibility that a conveyance delay will occur in the subsequent paper.

In the present embodiment, when the conveyance delay of the sheet occurs, the image forming start time is set to the second time, the image formation is performed, and after the predetermined number of images are formed, the image forming start time is set to the first time. Return to the time. As a result, even if the paper has a large slip, it is possible to reliably prevent a conveyance delay in the succeeding paper.

The effects other than those described above are the same as those already described.

[Fourth Embodiment]
Next, an image forming apparatus according to the fourth exemplary embodiment will be described.

FIG. 14 is a diagram illustrating an example of a functional configuration of a control unit of the image forming apparatus according to the fourth embodiment. The control unit 200d of the image forming apparatus 100d includes an image forming control unit 203d, and the image forming control unit 203d includes an image forming start timing changing unit 210d. In addition, the image formation start time changing unit 210d includes a factor determining unit 216.

The factor determination unit 216 can determine whether the formation of the toner image is interrupted due to a factor other than the conveyance delay. Here, the factors other than the conveyance delay include an abnormality such as a jam when the paper feed tray of the image forming apparatus 100d runs out of paper, the cover (door) of the image forming apparatus 100d is in an open state, and the like. Is the case when occurs.

The image forming start time changing unit 210d changes the image forming start time to the second time when the conveyance delay of the paper P occurs. Further, when the image forming start time changing unit 210d changes the image forming start time to the second time and then the toner image forming is interrupted due to a factor other than the conveyance delay, the image forming start changing unit 210d may stop the toner image forming after the interruption. The image formation start time can be changed from the second time to the first time.

When the image formation start of the toner image is interrupted after the image formation start time is changed to the second time, the conveyance delay due to the slip of the paper may be eliminated. On the other hand, in the second time, the image formation start time is later than in the first time, and therefore, if the image formation start time is set to the second time, the productivity of the image forming apparatus may decrease.

In the present embodiment, after the image formation start time is changed to the second time, if the toner image formation is interrupted due to a factor other than the conveyance delay, the image formation start time is set after the toner image formation is interrupted. Return to the first time. As a result, it is possible to quickly eliminate the decrease in productivity of the image forming apparatus.

The effects other than those described above are the same as those already described.

Although the image forming apparatus according to the embodiment has been described above, the present invention is not limited to the above embodiment, and various modifications and improvements can be made within the scope of the present invention.

The embodiment also includes a method of controlling the image forming apparatus. For example, a control method of an image forming apparatus is a method of controlling an image forming apparatus that forms an image on a recording medium, and includes a carrying step of carrying the recording medium, and an image carrying operation with a first timing as an image forming start timing. An image forming step of forming a toner image on the body, a primary transfer step of primarily transferring the toner image to an intermediate transfer body, and a toner image primarily transferred on the intermediate transfer body at a predetermined secondary transfer position. A secondary transfer step of secondarily transferring to the recording medium, a detection step of detecting the recording medium conveyed by the conveying step, and an image forming control for controlling the formation of the toner image by the image forming step. The image forming control step starts the image formation of the toner image by the image forming step, and the toner image and the recording medium have their leading ends aligned at the secondary transfer position. The time to start the conveyance of the recording medium is equal to or more than a predetermined resist threshold, and the elapsed time from the time when the conveyance of the recording medium by the conveying step is started is less than a jam threshold time, When a conveyance delay occurs in which the recording medium is not detected in the detecting step, the image formation of the toner image is stopped, and a second time different from the first time when the recording medium is detected is formed. As a start timing, a re-imaging control step of restarting the formation of the toner image, and an image-forming start timing at which the toner image is formed by the image-forming step after the re-imaging control step is executed. And changing the image formation start time to the second time.

With such a method of controlling the image forming apparatus, it is possible to obtain the same effects as those of the image forming apparatus described above.

1 image forming unit 2 image carrier 15 transfer unit 16 intermediate transfer belt 17 driven roller 18 transfer drive roller 19 primary transfer roller 20 secondary transfer roller 21 belt cleaning unit 30 paper feed tray 31 registration sensor (an example of a detection unit)
32 registration roller pair 34 fixing unit 46 bottom plate 47 paper feed rollers 63, 63b operation panel 631 display unit 72 conveying units 100, 100a, 100b, 100c, 100d image forming apparatus 113 number setting unit 200, 200a, 200b, 200c, 200d control Unit 201 I/F unit 202 Conveyance control unit 203 Image forming control unit 204 Transfer control unit 205 Fixing control unit 206 Monitoring unit 207 Operating unit 208 Image writing control unit 209 Re-imaging control unit 210, 210a, 210b, 210c, 210d Image formation start timing changing unit 211 Time determination unit 212 Print request end determination unit 213 Number of times determination unit 214 Notification display control unit 215 Number of sheets determination unit 216 Factor determination unit

JP, 2010-60966, A

Claims (8)

An image forming apparatus for forming an image on a recording medium, comprising:
A transport unit for transporting the recording medium,
An image forming unit that forms a toner image on the image carrier with the first time as an image formation start time,
A primary transfer portion that primarily transfers the toner image onto an intermediate transfer member;
A secondary transfer portion that secondarily transfers the toner image primarily transferred onto the intermediate transfer member to the recording medium at a predetermined secondary transfer position;
A detection unit that detects the recording medium conveyed by the conveyance unit,
An image forming control unit that controls the formation of the toner image by the image forming unit,
The image forming control unit,
The time from the start of the formation of the toner image by the image forming unit to the start of the conveyance of the recording medium in advance so that the leading edge of the toner image and the recording medium are aligned at the secondary transfer position. Within a predetermined registration threshold time or more, the time elapsed from the time when the conveyance of the recording medium by the conveyance unit is started is less than a jam threshold time, and the conveyance delay that the recording medium is not detected by the detection unit is delayed. When it occurs, the formation of the toner image is stopped, and the formation of the toner image is restarted with the image formation start time being the second time different from the first time when the recording medium is detected. A re-imaging control unit to
After performing the re-imaging operation by the re-imaging control unit, the image forming start time at which the toner image is formed by the image forming unit is changed to the second time. And an image forming apparatus having a unit. The image forming start time changing unit has a print request end judging unit that judges whether or not all the print requests started when the conveyance delay has occurred are completed, and the image forming start time is set to the second image forming start time. The image forming apparatus according to claim 1, wherein the image forming start time is changed to the first time when the print request is completed after the change to the time. The image forming start timing changing unit determines whether the number of occurrences of the conveyance delay is equal to or greater than a predetermined number, and whether all the image print requests started when the conveyance delay occurs are completed. When the number of occurrences of the conveyance delay is equal to or greater than a predetermined number after the image formation start time is changed to the second time, the print request ends. The image forming apparatus according to claim 1, wherein the image forming start time is changed to the first time when the image forming operation is performed. The image forming apparatus according to claim 3, further comprising a display unit that displays a predetermined notification when the number of occurrences of the conveyance delay is a predetermined number of times or more. The image forming start timing changing unit has a number determining unit that determines whether or not a predetermined number of images have been formed, and after changing the image forming start time to the second period, the predetermined number is set. The image forming apparatus according to claim 1, wherein the image formation start time is changed to the first time when the number of images is formed. The image forming apparatus according to claim 5, further comprising a number setting unit that sets the predetermined number according to an input. The image forming start timing changing unit has a factor determining unit that determines whether or not the image formation of the toner image is interrupted due to a factor other than the conveyance delay, and sets the image forming start timing to the second period. After the change, when the formation of the toner image is interrupted due to a factor other than the conveyance delay, the image formation start time is changed to the first time after the interruption of the image formation of the toner image is completed. The image forming apparatus according to any one of 1 to 6. A method of controlling an image forming apparatus for forming an image on a recording medium, comprising:
A carrying step of carrying the recording medium,
An image forming step of forming a toner image on the image carrier with the first time as an image forming start time;
A primary transfer step of primarily transferring the toner image onto an intermediate transfer member,
A secondary transfer step of secondary-transferring the toner image primarily transferred onto the intermediate transfer member to the recording medium at a predetermined secondary transfer position;
A detecting step of detecting the recording medium conveyed by the conveying step,
An image forming control step of controlling the image formation of the toner image by the image forming step,
The image forming control step,
The time from the start of the formation of the toner image in the image formation step to the start of the conveyance of the recording medium in advance so that the leading edge of the toner image and the recording medium are aligned at the secondary transfer position. A conveyance delay occurs in which the recording medium is not detected by the detection step within a time that is equal to or more than a predetermined resist threshold and is less than a jam threshold time after the conveyance of the recording medium by the conveyance step is started. In this case, the formation of the toner image is stopped, and the formation of the toner image is restarted with the image formation start time being the second time different from the first time when the recording medium is detected. Re-imaging control process,
An image forming start time changing step of changing the image forming start time when the image forming of the toner image is started by the image forming step to a second time after the image forming step is executed. Device control method.

Images