JP2012194405A - Image forming apparatus and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend the life of means for collecting a toner image on a transfer body.SOLUTION: A printing control part 18 separates a first cleaning blade from a direct transfer belt when cumulative contact time of the first cleaning blade exceeds a threshold in toner concentration correction processing during monochrome printing. The printing control part 18 then brings a second cleaning blade in contact with an intermediate transfer belt and allows the direct transfer belt to approach the intermediate transfer belt to transfer a toner pattern image for concentration correction of a color "K" from the direct transfer belt to the intermediate transfer belt. After that, the printing control part 18 allows a second toner pattern concentration detection sensor to detect the toner pattern image for concentration correction of the color "K" to perform toner concentration correction of the color "K" based on the detection result, and allows the second cleaning blade to collect the toner pattern image for concentration correction of the color "K" on the intermediate transfer belt.

Description

  The present invention relates to an image forming apparatus including a facsimile machine, a printer, a copier, and a multifunction machine, and a program comprising a procedure executed by a computer that controls the image forming apparatus.

  Conventionally, it has a plurality of photosensitive drums, and a black (K) image is transferred by a direct transfer method, and an image of each color (Y, M, C) of yellow, magenta, and cyan is transferred by an indirect transfer method. In a full-color image forming apparatus that is composed of a mixture of a transfer method and an indirect transfer method and can separate the intermediate transfer belt and the direct transfer belt, the density of each of the Y, M, and C toners is independent of the printing during monochrome image printing. There has been an image forming apparatus that performs correction (see, for example, Patent Document 1).

  However, in a full-color image forming apparatus that is composed of a mixture of the direct transfer method and the indirect transfer method as described above and can separate the intermediate transfer belt and the direct transfer belt, when monochrome printing continues continuously, the direct transfer method is performed directly at the time of toner density correction. The toner pattern formed on the transfer belt is collected directly by a cleaning blade installed on the transfer belt. At this time, the intermediate transfer belt is separated and is not operating.

  Therefore, compared with the cleaning blade on the intermediate transfer belt side, the cleaning blade of the direct transfer belt has a longer contact time with the direct transfer belt and is liable to deteriorate due to the friction. There was a problem of causing deterioration.

  The present invention has been made in view of the above points, and an object thereof is to extend the life of means for collecting a toner image on a transfer member.

  In order to achieve the above-mentioned object, the present invention transfers the toner image to a first transfer member or transfer paper conveyed by the first transfer member, and transfers the toner image to the second transfer member by the first transfer member. A second transfer means for transferring a toner image different from the toner image; an approach / separation means for approaching and separating the first transfer body and the second transfer body; and the first transfer body and the second transfer body by the approach / separation means. , The secondary transfer means for transferring the toner image of the first transfer body to the second transfer body or transferring the toner image of the second transfer body to the first transfer body, and the toner image of the first transfer body First density detecting means for detecting density, second density detecting means for detecting the density of the toner image on the second transfer body, first collection means for collecting the toner image on the first transfer body, and second transfer body A second collecting means for collecting the toner image and the first transfer A contact / separation means for bringing the first collection means into contact or separation with respect to the second transfer body, and an indicator for estimating the deterioration state of the first collection means. When correcting the density of the first deterioration measuring means for measuring the numerical value and the toner image density transferred to the first transfer member, when the count value of the first deterioration measuring means exceeds the reference value, the approaching / separating means The first transfer body and the second transfer body are brought close to each other, the first collection means is separated from the first transfer body by the contact / separation means, and the second collection means is brought into contact with the second transfer body to detect the second density. Provided is an image forming apparatus provided with a control means for causing a means to detect a toner image for toner density correction from a second transfer member.

In the image forming apparatus as described above, when the toner image is transferred by the first transfer unit or the secondary transfer unit to the transfer paper conveyed by the first transfer body, the control unit is configured to contact the contact point. It is preferable to have means for executing control for separating the first recovery means from the first transfer member by the separation means.
Further, in the image forming apparatus as described above, the control unit is configured to perform the first collection on the first transfer body by the contact / separation unit only when collecting the density correction toner image from the first transfer body. It is preferable to have means for executing control for bringing the means into contact.

  Further, in the image forming apparatus as described above, a second deterioration measurement unit that measures a count value of an index for estimating the deterioration state of the second recovery unit is provided, and the control unit transfers to the first transfer body. When correcting the toner image density and the toner image density transferred to the second transfer member, when the count value of the second deterioration measuring means exceeds the reference value, the approaching / separating means causes the first transfer. The first transfer means is brought into contact with the first transfer body by the contact / separation means, and the second recovery means is moved away from the second transfer body. The one density detecting means may have means for detecting a toner image for toner density correction from the first transfer member.

  Further, the first transfer means, the second transfer means, the approaching / separating means, the secondary transfer means, the first density detecting means, the second density detecting means, the first collecting means, and the second collecting means as described above are brought into contact with and separated from each other. Means, first deterioration measuring means, second deterioration measuring means, and (a) when correcting the density of the toner image transferred to the first transfer member, (a-1) the count value of the first deterioration measuring means is the second deterioration. When it is determined that the count value of the measuring means is exceeded, the first transfer body and the second transfer body are brought closer to each other by the approaching / separating means, and the first recovery means is separated from the first transfer body by the contact / separation means. (A-2) first deterioration measuring means, wherein the second transfer means is brought into contact with the second transfer body, and the second density detecting means is controlled to detect a toner image for toner density correction from the second transfer body. It was determined that the count value of the sample did not exceed the count value of the second deterioration measuring means In this case, the first transfer member and the second transfer member are separated from each other by the approaching / separating unit, the first collecting unit is brought into contact with the first transfer member by the contact / separating unit, and the second collecting unit is moved from the second transfer unit to the second collecting unit. And controlling the first density detecting means to detect the toner image for correcting the toner density from the first transfer body, and (b) controlling the toner image density transferred to the first transfer body and the second transfer body. When correcting the toner image density to be transferred, (b-1) when it is determined that the count value of the first deterioration measuring means exceeds the count value of the second deterioration measuring means, the approaching / separating means causes the first transfer body to The first transfer means is moved away from the first transfer body by the contact / separation means, the second recovery means is brought into contact with the second transfer body, and the first transfer is made to the second density detection means. Detect toner image for toner density correction from body (B-2) When it is determined that the count value of the first deterioration measuring means does not exceed the count value of the second deterioration measuring means, the approaching / separating means causes the first transfer body and the second transfer body to The first recovery unit is brought into contact with the first transfer member by the contact / separation unit and the second recovery unit is separated from the second transfer member, and the toner density correction from the first transfer member to the first density detection unit is performed. An image forming apparatus including a control unit that executes control for detecting a toner image for use is provided.

  In the image forming apparatus as described above, setting means for setting whether or not to enable the control means may be provided.

  Further, the first transfer means, the second transfer means, the approaching / separating means, the secondary transfer means, the first density detecting means, the second density detecting means, the first collecting means, and the second collecting means as described above are brought into contact with and separated from each other. A program comprising a procedure for causing a computer that controls the image forming apparatus including the means, the first deterioration measuring means, the second deterioration measuring means, and the control means to function as the image forming apparatus as described above is provided.

The image forming apparatus according to the present invention can extend the life of the means for collecting the toner image on the transfer member.
In addition, the program according to the present invention can cause a computer that controls the image forming apparatus to realize a function for extending the life of the means for collecting the toner image on the transfer body.

FIG. 2 is a block diagram illustrating a functional configuration of a printer unit in the image forming apparatus according to the embodiment of the present invention. FIG. 2 is a block diagram illustrating a hardware configuration of a printer unit in the image forming apparatus according to the embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of main parts related to transfer of the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a diagram illustrating a configuration of main parts related to transfer of the image forming apparatus according to the embodiment. FIG. 4 is a diagram illustrating a configuration of main parts related to transfer of the image forming apparatus according to the embodiment.

FIG. 6 is an explanatory diagram regarding toner image transfer using a secondary transfer bias unit. FIG. 2 is a flowchart showing toner density correction processing during printing in the print control unit shown in FIG. 1.

FIG. 8 is an explanatory diagram for explaining an operation of a main part related to transfer in the toner density correction process shown in FIG. 7. FIG. 8 is an explanatory diagram for explaining an operation of a main part related to transfer in the toner density correction process shown in FIG. 7.

FIG. 10 is a flowchart showing another toner density correction process during printing in the print control unit shown in FIG. 1. FIG. 11 is an explanatory diagram for explaining an operation of a main part related to transfer in the toner density correction processing shown in FIG. 10.

FIG. 11 is an explanatory diagram for explaining an operation of a main part related to transfer in the toner density correction process shown in FIG. 10. FIG. 10 is a flowchart showing another toner density correction process at the time of printing in the print control unit shown in FIG. 1.

FIG. 10 is a diagram illustrating an example of a setting screen for setting whether or not toner density correction processing is performed during printing and a threshold value for cumulative contact time in an image forming apparatus according to an embodiment.

Hereinafter, embodiments for carrying out the present invention will be specifically described with reference to the drawings.
FIG. 1 is a block diagram illustrating a functional configuration of a printer unit in an image forming apparatus according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a hardware configuration of the printer unit in the image forming apparatus according to the embodiment of the present invention.
3 to 5 are diagrams showing the configuration of the main part related to the transfer of the image forming apparatus according to the embodiment of the present invention.

  The image forming apparatus according to the embodiment is an image forming apparatus including a facsimile apparatus, a printer (printing apparatus), a copying machine, and a multifunction peripheral that print full-color and monochrome images on paper (transfer paper). The portions related to transfer and toner image collection are shown and described, and the well-known portions not directly related to the invention are not shown and described.

  As shown in FIG. 2, the main part of the hardware configuration of the image forming apparatus according to the embodiment includes a printer unit 1, a controller 20, a motor 21, a motor 22, and load units 23. The control system includes a CPU 24, ROM 25, RAM 26, direct transfer drive motor interface (I / F) section 27, driver 28, indirect transfer drive motor interface (I / F) section 29, driver 30, and input output (I / O). A control unit 31 is provided, and these units are connected to each other via a bus so that instructions and data can be exchanged.

  The CPU 24 executes a program stored in the ROM 25, and is realized by a microcomputer that also includes a CPU, a ROM, and a RAM. An instruction related to printing that is input from the controller 20 that controls the entire image forming apparatus. It controls the entire printer unit 1 (including control commands), reception of image data to be printed, and transmission / reception control of operation instructions related to toner image transfer and collection during toner density correction.

The ROM 25 is a rewritable non-volatile memory such as an EEPROM, for example, and includes the program executed by the CPU 24 and the amplitude of the operation of the drive unit including various rollers and belts related to printing and toner density correction and collection of the image forming apparatus. • Parameters such as phase value are also stored.
The RAM 26 is a readable / writable memory used for work when the CPU 24 executes various processes.

The direct transfer drive motor I / F unit 27 is an interface that transmits a drive instruction from the CPU 24 to a driver 28 that controls the drive of the motor 21.
The driver 28 controls the rotational drive of the motor 21 based on the drive instruction from the CPU 24 received via the direct transfer drive motor I / F unit 27.

  The motor 21 is a motor that drives each part including the photoconductor (K photoconductor) 40, the transfer roller 44, and the transport roller 45 of FIG. 3 related to direct transfer at the time of printing and toner density correction in the image forming apparatus.

The indirect transfer driving motor I / F unit 29 is an interface that transmits a driving instruction from the CPU 24 to a driver 30 that controls driving of the motor 22.
The driver 30 controls driving of the motor 22 based on a driving instruction from the CPU 24 received via the indirect transfer driving motor I / F unit 29.

The motor 22 includes a photoconductor 40, a photoconductor (Y photoconductor) 41, a photoconductor (M photoconductor) 42, and a photoconductor related to indirect transfer during printing and toner density correction in the image forming apparatus. (C photoconductor) 43 and motors for driving each part including the secondary transfer roller 51.
The I / O control unit 31 controls input / output of various commands and data between the CPU 24 and each load unit 23.

  Each load unit 23 is an image reading device that reads an image of a document according to instructions and data from the CPU 24, a charging device that charges the surface of each photoconductor, an exposure device that forms an electrostatic latent image on each photoconductor, The image forming apparatus includes a developing device that visualizes the electrostatic latent image of each photoconductor with a toner image of each color, a fixing device that fixes the toner image transferred onto the transfer paper, and a paper feeding device. Since these parts are known, illustration and description are omitted.

Each load unit 23 detects the density of the toner pattern image for density correction at the time of toner density correction, the first toner pattern density detection sensor 48 and the second toner pattern density detection sensor 52 of FIG. 3, and the direct of FIG. It includes a well-known motor, clutch, and solenoid, not shown, which are a mechanism unit that moves the transfer belt 46 and the intermediate transfer belt 50 closer to and away from each other.
The direct transfer belt 46 in FIG. 3 corresponds to a first transfer member, and the intermediate transfer belt 50 in FIG. 3 corresponds to a second transfer member.

  Further, each load unit 23 is a mechanism unit that causes the first cleaning blade 49 that collects the density correction toner pattern image transferred to the direct transfer belt 46 of FIG. A known motor, clutch, and solenoid (not shown) and a second cleaning blade 53 that collects the density correction toner pattern image transferred to the intermediate transfer belt 50 in FIG. It includes a motor, a clutch, and a solenoid (not shown), which are mechanisms that are separated.

  The printer unit 1 is realized by the CPU 24 reading a program from the ROM 25 and executing the procedure of the program using the RAM 26 as a work area. The direct transfer control unit 12, the indirect transfer control unit 13, 2 shown in FIG. The function units of the next transfer control unit 14, the toner density correction control unit 15, the cleaning control unit 16, the measurement unit 17, and the print control unit 18 are generated on the main storage device.

  Also, in FIG. 1, the hardware configuration of the image forming apparatus is used as a functional unit, and a K image forming unit (K image forming unit) 2, a Y image forming unit (Y image forming unit) 3, an M image forming unit (M image) Forming unit) 4, C image forming unit (C image forming unit) 5, direct transfer unit 6, indirect transfer unit 7, secondary transfer unit 8, sensor unit 9, cleaning unit (cleaning unit) 10, and operation display unit 11. Is shown.

The direct transfer control unit 12 in FIG. 1 controls the K image forming unit 2 to form and directly transfer a K (black) toner image on transfer paper during full-color printing and monochrome printing, and during toner density correction. It controls the formation and direct transfer of the K density correction toner pattern image.
That is, the direct transfer control unit 12 functions as the first transfer unit that transfers the toner image to the first transfer member or the transfer sheet conveyed by the first transfer member together with the photosensitive member 40 of FIG.

  The indirect transfer control unit 13 controls the Y image forming unit 3, the M image forming unit 4, and the C image forming unit 5 to transfer a Y (yellow) toner image and M (magenta) toner image onto a transfer sheet during full color printing. Controls the formation and indirect transfer of toner images or C (cyan) toner images, and the control of forming and indirectly transferring Y, M, and C density correction toner pattern images during toner density correction. .

  That is, the indirect transfer control unit 13 is different from the toner image transferred to the second transfer body by the first transfer unit together with the Y image forming unit 3, the M image forming unit 4 and the C image forming unit 5 of FIG. Fulfills the function of a second transfer means for transferring.

  The secondary transfer control unit 14 controls the secondary transfer unit 8 to move the conveying roller 45 or the secondary transfer roller 51 in FIG. 3 during direct transfer and indirect transfer, thereby moving the direct transfer belt in FIG. 46 and controls the intermediate transfer belt 50 to approach and separate in the vicinity of the secondary transfer roller 51. Further, it controls the voltage application of the secondary transfer bias unit 47.

That is, the secondary transfer control unit 14 functions as an approaching / separating unit that moves the first transfer member and the second transfer member closer to and away from the secondary transfer unit 8 of FIG.
In addition to the secondary transfer unit 8 shown in FIG. 1, the secondary transfer control unit 14 displays a second transfer image on the first transfer body when the first transfer body and the second transfer body are approached by the approaching / separating means. Functions of secondary transfer means for transferring to the transfer body or transferring the toner image of the second transfer body to the first transfer body, and means for transferring the toner image of the first transfer body or the toner image of the second transfer body to transfer paper Fulfill.

  The toner density correction control unit 15 in FIG. 1 applies to the photoconductors 40 to 43 in FIG. 3 based on information indicating the density of each K, Y, M, and C density correction toner pattern image detected by the sensor unit 9. Control processing for correcting the density when forming toner images of K, Y, M, and C, respectively.

The cleaning control unit 16 in FIG. 1 controls the cleaning unit 10, the contact and separation of the first cleaning blade 49 with respect to the direct transfer belt 46 in FIG. 3, and the second cleaning blade 53 with respect to the intermediate transfer belt 50 in FIG. 3. Each operation of contact and separation is controlled.
That is, the cleaning control unit 16 functions as an abutment / separation unit that abuts or separates the first recovery unit from the first transfer member and abuts or separates the second recovery unit from the second transfer member. Fulfill.

  1 has a timer function and an accumulated time holding function, and measures and holds the accumulated contact time when the first cleaning blade 49 is brought into contact with the direct transfer belt 46 in FIG. 3, the accumulated contact time when the second cleaning blade 53 is brought into contact with the intermediate transfer belt 50 in FIG. 3 is measured and held. Each accumulated contact time held is referred to by the print control unit 18.

That is, the measurement unit 17 measures the first degradation measurement unit that measures the count value of the index that estimates the deterioration state of the first recovery unit and the first count value of the index that estimates the degradation state of the second recovery unit. 2 Performs the function of deterioration measuring means.
As a means for estimating the deterioration state of the first cleaning blade 49 and the second cleaning blade 53, other known techniques may be applied in addition to the measurement unit as described above.
The print control unit 18 in FIG. 1 controls each unit of the printer unit 1 and performs control processing at the time of toner density correction according to the invention.

The K image forming unit 2 in FIG. 1 includes the photoconductor 40 in FIG. 3, and a charging device, an exposure device, and a developing device (not shown) for forming a black toner image on the photoconductor 40.
The Y image forming unit 3 in FIG. 1 includes the photoconductor 41 in FIG. 3, and a charging device, an exposure device, and a developing device (not shown) for forming a yellow toner image on the photoconductor 41.

The M image forming unit 4 in FIG. 1 includes the photosensitive member 42 in FIG. 3, and a charging device, an exposure device, and a developing device (not shown) for forming a magenta toner image on the photosensitive member 42.
The C image forming unit 5 in FIG. 1 includes the photoconductor 43 in FIG. 3, and a charging device, an exposure device, and a developing device (not shown) for forming a cyan toner image on the photoconductor 43.

The direct transfer unit 6 in FIG. 1 includes the transfer roller 44, the transport roller 45, and the direct transfer belt 46 in FIG. 3.
The indirect transfer unit 7 of FIG. 1 includes the intermediate transfer belt 50 and the secondary transfer roller 51 of FIG.
The secondary transfer unit 8 includes the secondary transfer bias unit 47 of FIG. 3 and a motor, a clutch, and a solenoid (not shown) that move the transport roller 45. Further, a motor, a clutch, and a solenoid (not shown) for moving the secondary transfer roller 51 are included.

1 includes the first toner pattern density detection sensor 48 and the second toner pattern density detection sensor 52 shown in FIG.
The cleaning unit 10 in FIG. 1 includes a well-known motor, a clutch, and a solenoid (not shown) as a mechanism unit that directly contacts and separates the first cleaning blade 49 in FIG. It includes a motor, a clutch, and a solenoid (not shown) that are mechanisms for causing the second cleaning blade 53 to contact and separate from the intermediate transfer belt 50.

  The operation display unit 11 includes an input unit including a keyboard and a display unit including an LCD. The operation display unit 11 inputs user operation information for the print control unit 18 and displays various display screens from the print control unit 18.

  In the case of full-color printing on paper, the image forming apparatus moves the conveying roller 45 toward the intermediate transfer belt 50 (in the direction of arrow E in the figure) as shown in FIG. The direct transfer belt 46 and the intermediate transfer belt 50 are brought close to each other so that the image can be directly transferred to the transfer belt 46, and the first cleaning blade 49 is moved in the direction of the arrow C 'in the drawing to be separated from the direct transfer belt 46.

Then, a black toner image (hereinafter referred to as “K”) is formed on the photosensitive member 40, and the above K is placed on a sheet of paper (not shown) that is directly conveyed by the transfer belt 46 in the direction of arrow B in the figure. The color toner image is transferred at the point of the transfer roller 44 (this is a direct transfer system).
Since the detailed contents of the processing at the time of forming the toner image on the photoconductor 40 are known, the description thereof will be omitted.

  On the other hand, the second cleaning blade 53 is moved in the direction indicated by the arrow D in the drawing so as to come into contact with the intermediate transfer belt 50, and a yellow (hereinafter referred to as “Y”) toner image is transferred to the photoconductor 41. A magenta (hereinafter referred to as “M”) toner image is formed on the photoconductor 43, and a cyan (hereinafter referred to as “C”) toner image is formed on the photoreceptor 43, and is conveyed in the direction of arrow A in the figure. The toner images of the respective colors Y, M, and C are sequentially transferred onto the intermediate transfer belt 50, whereby a toner image obtained by superimposing the toner images of the colors Y, M, and C on the intermediate transfer belt 50 is formed. Form.

Since the detailed contents of the processing at the time of forming the toner image on the photoconductors 41 to 43 are known, the description thereof will be omitted.
Thereafter, the superimposed toner image is directly transferred to the transfer belt 46 side at the point of the secondary transfer roller 51 by the voltage applied by the secondary transfer bias unit 47, and the toner image of K color is transferred. Transfer on paper (this is the indirect transfer method).
Then, the toner image is fixed on the sheet, and the residual toner image on the intermediate transfer belt 50 is collected by the second cleaning blade 53 to complete the printing.
In this way, it is possible to print a full color image using K, Y, M, and C toners on the paper.

  Next, when performing monochrome printing on a sheet, the toner image on the intermediate transfer belt 50 is moved by moving the conveying roller 45 in the direction opposite to the intermediate transfer bell 50 (indicated by an arrow E ′ in the figure) as shown in FIG. However, the direct transfer belt 46 and the intermediate transfer belt 50 are separated to an interval at which the direct transfer belt 46 cannot be transferred, and the first cleaning blade 49 is moved away from the direct transfer belt 46 in the direction of arrow C ′ in the figure. Since it is not necessary to transfer the Y, M, and C toner images, the driving of the portion related to indirect transfer is stopped.

Then, a K-color toner image is formed on the photoconductor 40, and the K-color toner image is directly transferred onto the sheet (not shown) conveyed by the transfer belt 46 in the direction indicated by the arrow B in FIG. Transcript with.
Then, the toner image is fixed on the paper and printing is completed.

Note that the approach and separation of the direct transfer belt 46 and the intermediate transfer belt 50 may be configured such that the intermediate transfer belt 50 approaches and separates from the direct transfer belt 46 as shown in FIG.
In this case, by moving the secondary transfer roller 51 directly toward the transfer belt 46 (in the direction indicated by arrow F in the figure), the intermediate transfer belt can be moved to an interval at which the toner image on the intermediate transfer belt 50 can be directly transferred to the transfer belt 46. 50 and the direct transfer belt 46 are brought close to each other, and the first cleaning blade 49 is moved in the direction of the arrow C ′ in the drawing to be separated from the direct transfer belt 46.

  Then, a K-color toner image is formed on the photoconductor 40, and the K-color toner image is directly transferred onto the sheet (not shown) conveyed by the transfer belt 46 in the direction indicated by the arrow B in FIG. Transcript with.

  On the other hand, the second cleaning blade 53 is moved in the direction of arrow D in the figure and brought into contact with the intermediate transfer belt 50 to form Y, M, and C color toner images on the photoreceptors 41 to 43, respectively. On the intermediate transfer belt 50 conveyed in the direction A, a toner image is formed by superimposing the toner images of the colors Y, M, and C.

Thereafter, the superimposed toner image is directly transferred to the transfer belt 46 side at the point of the secondary transfer roller 51 by the voltage applied by the secondary transfer bias unit 47, and the toner image of K color is transferred. Transfer on paper.
Then, the toner image is fixed on the sheet, and the residual toner image on the intermediate transfer belt 50 is collected by the second cleaning blade 53 to complete the printing.

  Next, when performing monochrome printing on a sheet, the toner image on the intermediate transfer belt 50 is directly transferred to the transfer belt 46 by moving the secondary transfer roller 51 in the direction opposite to the direct transfer belt 46 (indicated by arrow F ′ in the figure). Therefore, the intermediate transfer belt 50 and the direct transfer belt 46 are not separated from each other until the transfer is impossible, and it is not necessary to transfer the Y, M, and C toner images. Further, the first cleaning blade 49 is moved in the direction of the arrow C ′ in the drawing to be separated directly from the transfer belt 46.

Then, a K-color toner image is formed on the photoconductor 40, and the K-color toner image is directly transferred onto the sheet (not shown) conveyed by the transfer belt 46 in the direction indicated by the arrow B in FIG. To complete the printing by fixing the toner image on the paper.
As for the configuration of the approach and separation functions shown in FIGS. 4 and 5, either one or both configurations may be selected and mounted depending on the machine layout of the image forming apparatus.

  In this embodiment, the case where toner images of the respective colors Y, M, and C are formed on the photoconductors 41 to 43 is shown. However, the color of the toner image formed on each of the photoconductors 41 to 43 is shown. May be assigned to other colors.

Next, transfer of a toner image using the secondary transfer bias unit 47 will be described.
FIG. 6 is an explanatory diagram for the transfer of a toner image using the secondary transfer bias unit 47.

  FIG. 6A shows the K density correction toner pattern image 60 directly transferred onto the transfer belt 46 and the Y, M, and C density correction toners transferred onto the intermediate transfer belt 50. A pattern image 61 is shown, and the charging polarity of each toner is positive (indicated by a circle including “+” in the drawing). In FIG. 6, for convenience, one Y, M, and C density correction toner pattern images 61 are shown.

  The K color density correction toner pattern image 60 and the Y, M, and C color density correction toner pattern images 61 are moved in the directions indicated by arrows A and B in the drawing by the movement of the direct transfer belt 46 and the intermediate transfer belt 50, respectively. Move to.

  Here, when the K-color density correction toner pattern image 60 directly transferred onto the transfer belt 46 is transferred onto the intermediate transfer belt 50, as shown in FIG. When a bias voltage for generating a positive charge is applied to the toner, the K-color density correction toner pattern image 60 on the transfer belt 46 is directly transferred to the intermediate transfer belt by the repulsive force of the positive charge generated by the secondary transfer bias unit 47. 50 (indicated by reference numeral 60 'in FIG. 6B).

  On the other hand, when the Y to C color correction toner pattern images 61 transferred onto the intermediate transfer belt 50 are directly transferred onto the transfer belt 46, as shown in FIG. When a bias voltage for generating a negative charge (indicated by a circle including “-” in the drawing) is applied to the portion 47, the negative transfer generated by the secondary transfer bias portion 47 causes an attractive force on the intermediate transfer belt 50. The Y to C density correction toner pattern images 61 are directly transferred onto the transfer belt 46 (indicated by reference numeral 61 'in FIG. 6C).

  Further, during normal full-color image printing, each of the Y to C toner images transferred onto the intermediate transfer belt 50 is transferred to the secondary transfer roller onto the K toner image transferred directly onto the transfer belt 46. At the point 51, the secondary transfer bias unit 47 charges the toner directly to the transfer belt 46, and superimposes it on the K toner image transferred onto the transfer belt 46.

When the toner charging polarity is negative, in order to directly transfer the toner image on the transfer belt 46 onto the intermediate transfer belt 50, a negative charge is generated at the secondary transfer bias portion 47 and the toner image is transferred onto the intermediate transfer belt 50. In order to directly transfer the toner image onto the transfer belt 46, it is preferable to generate a positive charge at the secondary transfer bias portion 47.
In this way, the toner image can be directly transferred between the transfer belt 46 and the intermediate transfer belt 50 by changing the polarity charged by the secondary transfer bias unit 47.

  In this image forming apparatus, the toner density correction processing of each color toner image is periodically performed during printing. For example, when the cumulative number of prints exceeds a preset number, the toner density correction process for each color toner image is performed. In this toner density correction process, only the K toner density correction is performed when the cumulative number of prints for monochrome printing exceeds a preset number, and the total number of prints for full color printing exceeds K. , Y, M, and C toner density corrections are performed.

  The basic operation of this toner density correction process is to transfer a K color density correction toner pattern image onto the transfer belt 46 directly by the photosensitive member 40 and to use the first toner pattern density detection sensor 48 for the K color toner density. After detecting information for correcting the toner density of K color from the toner pattern image for correcting the K color density, the first cleaning blade 49 collects the toner pattern image for correcting the K color density.

  On the other hand, for the Y, M, and C toner densities, the Y, M, and C density correction toner pattern images are transferred onto the intermediate transfer belt 50 by the photoconductors 41 to 43, and the second toner pattern density detection is performed. After the sensor 52 detects Y, M, and C color toner density correction information from the Y, M, and C density correction toner pattern images, respectively, the second cleaning blade 53 uses the Y, M, and C color density correction information. The toner pattern image for density correction is collected.

  However, the first cleaning blade 49 and the second cleaning blade 53 collect the toner images of the direct transfer belt 46 and the intermediate transfer belt 50, respectively, and clean the belt surface. Since they are brought into contact with each other, the belt gradually deteriorates due to friction with the belt, and as the use period becomes longer, the deterioration progresses and there is a possibility that the toner image may not be collected.

  Further, for example, when the number of times of monochrome printing is large, the number of times of K-color toner density correction is larger than the number of times of Y-, M-, and C-color toner density corrections, and the first cleaning blade 49 is deteriorated. It becomes easy to proceed.

  As described above, when the cleaning of the belt surface is insufficient due to the deterioration of the cleaning blade, there is a possibility that the paper at the time of printing is soiled by the residual toner on the belt surface or the toner density correction cannot be performed correctly due to the accumulation of the residual toner.

  Therefore, in the image forming apparatus of this embodiment, during the toner density correction process, the usage time of the first cleaning blade 49 or the second cleaning blade 53 is not biased, and one cleaning performance is not deteriorated early. By switching between the toner density correction using the direct transfer belt 46 and the toner density correction using the intermediate transfer belt 50, the deterioration of one of the first cleaning blade 49 and the second cleaning blade 53 is prevented from progressing. As a result, the lifetime of the first cleaning blade 49 and the second cleaning blade 53 is extended.

Next, control processing during printing in the print control unit 18 will be described.
The print control unit 18 functions as a control unit according to the invention, and includes all the following functions (1) to (5) as functions related to control processing including toner density correction processing during printing. Thus, it is possible to implement a function set to enable a function selected in advance from the operation display unit 11 by the user.

In the following description, processing of each function will be described.
In this embodiment, a process when all the functions (1) to (5) are performed will be described. However, any one of (1) to (5) or at the manufacturing stage of the image forming apparatus is described. A plurality of functions may be installed, and may be operated when the user makes settings for enabling the functions from the operation display unit 11.

(1) When correcting the toner density when forming the toner image to be transferred to the first transfer body by the first transfer means to a preset toner density, the count value measured by the first deterioration measuring means is preset. When it is determined that the reference value is exceeded, the first transfer member and the second transfer member are brought into the close state by the approaching / separating unit, and the first recovery unit is put in the separated state from the first transfer member by the contact / separation unit. At the same time, the second recovery unit is brought into contact with the second transfer body, and after the density transfer toner image is transferred to the first transfer body by the first transfer unit, the density correction toner image is first transferred by the secondary transfer unit. Concentration correction toner image from the second transfer body by the second density detection means as information for toner density correction when forming a toner image transferred from the transfer body to the second transfer body and transferred by the first transfer means. After detecting the first control function for recovering the density correction toner image from the second transfer body by the second recovering means.

(2) When the toner image is transferred to the transfer paper conveyed by the first transfer member by the first transfer unit or the secondary transfer unit, the first recovery unit is separated from the first transfer member by the contact / separation unit. Second control function.
(3) A third control function for bringing the first collection unit into contact with the first transfer member by the contact / separation unit only when collecting the density correction toner image from the first transfer member.

(4) The toner density when forming the toner image to be transferred to the first transfer body by the first transfer means and the toner density when forming the toner image to be transferred to the second transfer body by the second transfer means, respectively. When correcting to a preset toner density, when it is determined that the count value measured by the second deterioration measuring unit exceeds a preset reference value, the first transfer member and the second transfer unit are moved by the approaching / separating unit. The first recovery means is brought into contact with the first transfer body by the contact / separation means and the second collection means is separated from the second transfer body by the contact / separation means. The toner image for density correction is transferred to the body, and another toner image for density correction transferred to the second transfer body by the second transfer means is transferred from the second transfer body to the first transfer body by the secondary transfer means, The density correction toner image and the other density correction toner image from the first transfer body by the first density detection unit as information for correcting the toner density when forming the toner images to be transferred respectively by the first transfer unit and the second transfer unit. And a fourth control function for collecting the density correction toner image and other density correction toner images from the first transfer member by the first collection means.

(5) When correcting the toner density when forming the toner image to be transferred to the first transfer body by the first transfer means to a preset toner density, the count value measured by the first deterioration measuring means is the second value. When it is determined that the count value measured by the deterioration measuring means is exceeded, the first transfer body and the second transfer body are brought into an approaching state by the approaching / separating means, and the first recovery is performed from the first transfer body by the contact / separation means. The second transfer unit is brought into contact with the second transfer member, the density transfer toner image is transferred to the first transfer member by the first transfer unit, and the first transfer is performed by the secondary transfer unit. The toner image for density correction from the second transfer body by the second density detection means as information for toner density correction when forming a toner image transferred from the body to the second transfer body and transferred by the first transfer means After detection, the fifth control function for recovering the density correction toner image from the second transfer body by the second recovering means.

(6) When it is determined that the count value measured by the first degradation measurement unit does not exceed the count value measured by the second degradation measurement unit, the first transfer body and the second transfer body are separated by the approaching / separating unit. The first recovery unit is brought into contact with the first transfer member by the contact / separation unit, and the second recovery unit is separated from the second transfer member. After the correction toner image is transferred and the density correction toner image is detected from the first transfer body by the first density detection means as information for correcting the toner density when forming the toner image to be transferred by the first transfer means. A sixth control function of collecting the density correction toner image from the first transfer member by the first collecting means.

(7) The toner density when forming the toner image to be transferred to the first transfer body by the first transfer means and the toner density when forming the toner image to be transferred to the second transfer body by the second transfer means, respectively. When correcting to a preset toner density, when it is determined that the count value measured by the first deterioration measurement unit exceeds the count value measured by the second degradation measurement unit, the first transfer is performed by the approaching / separating unit. The first transfer means is moved away from the first transfer body by the contact / separation means, and the second recovery means is brought into contact with the second transfer body. The toner image for density correction transferred to the first transfer body by the means is transferred from the first transfer body to the second transfer body by the secondary transfer means, and another density correction toner is transferred to the second transfer body by the second transfer means. The toner image is transferred from the first transfer member by the second density detecting unit as information for correcting the toner density when the toner image is transferred and formed by the first transfer unit and the second transfer unit, respectively. A seventh control function for collecting the density correction toner image and the other density correction toner image from the second transfer member by the second collection unit after detecting the other density correction toner images;

(8) The toner density when forming the toner image to be transferred to the first transfer body by the first transfer means and the toner density when forming the toner image to be transferred to the second transfer body by the second transfer means, respectively. When correcting to a preset toner density, when it is determined that the count value measured by the first deterioration measurement unit does not exceed the count value measured by the second degradation measurement unit, the first transfer is performed by the approaching / separating unit. The first transfer means is brought into contact with the first transfer body by the contact / separation means, and the second collection means is moved away from the second transfer body. The toner image for density correction is transferred to the first transfer body by the means, and the other toner image for density correction transferred to the second transfer body by the second transfer means is transferred from the second transfer body by the secondary transfer means. A toner image for density correction from the first transfer body by the first density detection means as information for correcting the toner density when forming toner images transferred to one transfer body and transferred respectively by the first transfer means and the second transfer means. And another density correction toner image are detected, and an eighth control function for executing control to collect the density correction toner image and the other density correction toner image from the first transfer member by the first collection means .

  Further, the print control unit 18 also functions as a setting unit that sets whether to enable each of the first control function to the eighth control function.

FIG. 7 is a flowchart showing toner density correction processing during printing in the print control unit 18 shown in FIG.
FIG. 8 and FIG. 9 are explanatory diagrams for explaining the operation of the main part related to the transfer in the toner density correction processing shown in FIG.

  This process is a process when the function (1) is enabled in the print control unit 18. In particular, when this process is executed when monochrome image printing is performed more than full-color image printing, the cleaning blade is deteriorated. Can be suppressed.

  The print control unit 18 executes the following steps 1 to 20 for the printing process including the toner density correction process. In this process, during printing on the paper, the first cleaning blade 49 is in contact with the direct transfer belt 46 and the second cleaning blade 53 is in contact with the intermediate transfer belt 50, respectively. The belt surface is cleaned by the conveyance movement of the direct transfer belt 46 and the intermediate transfer belt 50.

(Step (indicated by “S” in the figure) 1)
The print controller 18 determines whether or not the cumulative number of prints exceeds 500 during printing of a monochrome image on a sheet. If not, the toner density correction process is not performed, and the process of step 1 is not performed. The determination process is repeated and the printing process is continued.

If it is determined that the number of printed sheets exceeds 500, it is determined that the toner density correction process is to be performed, and the process proceeds to Step 2.
As described above, the toner density correction process is performed every time the number of printed sheets exceeds 500, thereby maintaining the image quality of printing by setting the toner density to the correct density.

(Step 2)
The print control unit 18 accesses the measurement unit 17, reads the accumulated contact time of the first cleaning blade 49 stored in the measurement unit 17, and the time during which the first cleaning blade 49 is in direct contact with the transfer belt 46. It is determined whether or not the accumulated contact time exceeds 60 minutes set in advance. If it is determined that the cumulative contact time has exceeded, the process proceeds to step 3, and if not, the process proceeds to step 14.

  The cumulative contact time is a count value of an index for estimating the deterioration state of the first cleaning blade 49. For example, 60 minutes is set as the time when it is confirmed in advance that the deterioration has progressed through experiments.

(Step 3)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 controls the part including the motor, the clutch, and the solenoid that moves the first cleaning blade 49 of the cleaning unit 10, and controls the first cleaning blade 49. The first cleaning blade 49 is moved away from the direct transfer belt 46 by moving in the direction indicated by the arrow C ′ in FIG.

(Step 4)
The printing control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 controls a part including a motor, a clutch, and a solenoid that moves the conveyance roller 45 of the secondary transfer unit 8. 45 is moved in the direction indicated by arrow E in FIG. 9 so that the direct transfer belt 46 approaches the intermediate transfer belt 50 until the distance between the direct transfer belt 46 and the intermediate transfer belt 50 is such that the toner image can be transferred. Proceed to 5.

  If the configuration shown in FIG. 5 is adopted, in the process of step 4, the secondary transfer control unit 14 moves the secondary transfer roller 51 to bring the direct transfer belt 46 and the intermediate transfer belt 50 close to each other. Let

(Step 5)
The print control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 charges the toner image on the transfer belt 46 directly to the intermediate transfer belt 50 with respect to the secondary transfer bias unit 47. Apply a bias voltage for generating, and proceed to Step 6.

(Step 6)
The print control unit 18 controls the direct transfer control unit 12, and the direct transfer control unit 12 forms a K-color density correction toner pattern image on the photoconductor 40 and moves directly from the rotating photoconductor 40. The toner pattern image for K-color density correction (66 in FIG. 9) is transferred to the position of the transfer roller 44, and the process proceeds to Step 7.
The K-color density correction toner pattern image 66 on the direct transfer belt 46 is transferred onto the intermediate transfer belt 50 by the electric charges generated by the secondary transfer bias unit 47.

(Step 7)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the second toner pattern density detection sensor 52 of the sensor unit 9 to perform a K color density correction toner pattern image (see FIG. 9). 66 '), information for correcting the toner density obtained by the detection is acquired, and the process proceeds to step 8.

(Step 8)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 determines the black color based on the information for correcting the K toner density obtained from the second toner pattern density detection sensor 52. The toner density correction process is executed, and the process proceeds to step 9.
This black toner density correction process adjusts charging, exposure, or development when forming a K-color toner image on the photoconductor 40. Since this process is well-known, detailed description thereof is omitted.

(Step 9)
The print control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 uses the second cleaning blade 53 of the cleaning unit 10 to perform a K color density correction toner pattern image on the intermediate transfer belt 50 (66 "in FIG. 9). ) Is collected, and the process proceeds to Step 10.

(Step 10)
The print control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 turns off the application of the bias voltage to the secondary transfer bias unit 47 (stops the application), and proceeds to Step 11.
The operation of turning off the application of the bias voltage to the secondary transfer bias unit 47 is performed after the K color density correction toner pattern has been transferred onto the intermediate transfer belt 50, thereby consuming the image forming apparatus. Power can be saved.

(Step 11)
The printing control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 controls a part including a motor, a clutch, and a solenoid that moves the conveyance roller 45 of the secondary transfer unit 8. 8 is moved in the direction indicated by the arrow E ′ in FIG. 8, and the direct transfer belt 46 is separated from the intermediate transfer belt 50 until the distance between the direct transfer belt 46 and the intermediate transfer belt 50 is such that the toner image cannot be transferred. , Go to Step 12.

  If the configuration shown in FIG. 5 is adopted, in the process of step 12, the secondary transfer control unit 14 moves the secondary transfer roller 51 to separate the direct transfer belt 46 and the intermediate transfer belt 50 from each other. Let

(Step 12)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 controls the part including the motor, the clutch, and the solenoid that moves the first cleaning blade 49 of the cleaning unit 10, and controls the first cleaning blade 49. The first cleaning blade 49 is brought into direct contact with the transfer belt 46 by moving in the direction indicated by arrow C in FIG.

(Step 13)
The print control unit 18 determines whether or not monochrome image printing on the paper has been completed. If not, the process returns to step 1 and repeats the processing of steps 1 to 20.
In the processes in steps 3 to 12 described above, when the usage time of the first cleaning blade 49 becomes longer, the second cleaning blade 53 can be used to prevent early deterioration of the first cleaning blade 49.

(Step 14)
The print control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 keeps the first cleaning blade 49 in direct contact with the transfer belt 46 (the state of FIG. 8), and proceeds to step 15.

(Step 15)
The printing control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 keeps the direct transfer belt 46 and the intermediate transfer belt 50 separated from each other (the state shown in FIG. 8), and proceeds to Step 16. move on.

(Step 16)
The print control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 leaves the application of the bias voltage to the secondary transfer bias unit 47 off, and proceeds to step 17.

(Step 17)
The print control unit 18 controls the direct transfer control unit 12, and the direct transfer control unit 12 forms a K-color density correction toner pattern image on the photoconductor 40 and moves directly from the rotating photoconductor 40. A toner pattern image for K-color density correction (65 in FIG. 8) is transferred to the point of the transfer roller 44, and the process proceeds to Step 18.

(Step 18)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the first toner pattern density detection sensor 48 of the sensor unit 9 to perform a K color density correction toner pattern image (see FIG. 8). 65 ′) is detected, and information for correcting the toner density obtained by the detection is acquired.

(Step 19)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 determines the black color based on the information for correcting the K toner density obtained from the first toner pattern density detection sensor 48. The toner density correction process is executed, and the process proceeds to step 20.
This black toner density correction process adjusts charging, exposure, or development when forming a K-color toner image on the photoconductor 40. Since this process is well-known, detailed description thereof is omitted.

(Step 20)
The print control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 directly uses the first cleaning blade 49 of the cleaning unit 10 to directly print the K color density correction toner pattern image on the transfer belt 46 (65 ″ in FIG. 8). ) Is collected, and the process proceeds to Step 13.
The processing in steps 14 to 20 is normal control when the usage time of the first cleaning blade 49 does not exceed the reference time.

  In the above processing, the cumulative contact time of the second cleaning blade 53 is also checked, and if it exceeds 60 min, a message that informs that the cleaning blade is exhausted and recommends maintenance is displayed on the operation display unit 11. Good.

  The deterioration state of the first cleaning blade 49 is detected by the contact time between the first cleaning blade 49 and the direct transfer belt 46. When the accumulated contact time exceeds a certain threshold value (60 min in this embodiment), the first cleaning blade 49 is deteriorated. It is assumed that the cleaning blade 49 has been deteriorated.

Further, the friction between the first cleaning blade 49 and the direct transfer belt 46 varies depending on the amount of toner collected (supplied) by the first cleaning blade 49, and this also changes the degree of deterioration. Judgment may be made with consideration.
This is because the toner serves as a lubricant.

  Here, when transferring the density correction toner pattern image onto the intermediate transfer belt 50, not all of the density correction toner pattern images can be transferred onto the intermediate transfer belt 50 due to the difference in transfer rate. It is conceivable that toner remains on the surface.

  In this case, the first cleaning blade 49 is directly brought into contact with the transfer belt 46 again to collect the residual toner, but the density correction toner pattern image here is smaller than when it was first transferred. Therefore, even if the blade pressure of the first cleaning blade 49 (the pressing force when the first cleaning blade 49 is in direct contact with the transfer belt 46) is lowered, it can be recovered sufficiently.

From this, the friction between the direct transfer belt 46 and the first cleaning blade 49 can be reduced, so that the life of the first cleaning blade 49 can be further extended.
The print control process may be applied to a transfer belt cleaning process in a recovery process from a paper jam (JAM, paper jam) or abnormal stop in the image forming apparatus.

In the recovery process, the residual toner on the transfer belt is cleaned (collected) by the cleaning blade by idling the transfer belt.
In addition, when performing monochrome printing only by the direct transfer method, toner (printed image toner pattern image) other than the density correction toner pattern image formed in the non-image area on the direct transfer belt 46 at the time of toner density adjustment is transferred to the transfer paper. Transcribed.

  Therefore, during monochrome printing using only the direct transfer method, the direct transfer belt 46 and the first cleaning blade 49 are basically separated from each other, and the toner image including the density correction toner pattern image is directly on the transfer belt 46. It is preferable that the first cleaning blade 49 is brought into contact only when it is collected.

In the case of this control, the print control unit 18 operates with the functions (2) and (3) enabled.
Thereby, the contact time between the direct transfer belt 46 and the first cleaning blade 49 can be further reduced, and the life of the first cleaning blade 49 can be further extended.

  When the deterioration state of the cleaning blade on the direct transfer belt has progressed in monochrome continuous printing only with the direct transfer method, the cleaning blade on the direct transfer belt is separated and the toner pattern drawn on the transfer belt directly when adjusting the toner density Since the toner pattern is transferred onto the intermediate transfer belt and collected by the cleaning blade on the intermediate transfer belt, the contact time between the direct transfer belt and the cleaning blade on the direct transfer belt can be reduced. Can lead to longer life.

Next, another example of toner density correction processing at the time of printing in the print control unit 18 shown in FIG. 1 will be described.
FIG. 10 is a flowchart showing another example of toner density correction processing during printing in the print control unit 18 shown in FIG.
11 and 12 are explanatory diagrams for explaining the operation of the main part related to the transfer in the toner density correction processing shown in FIG.

  This processing is processing when the function (4) is enabled in the print control unit 18, and in particular, one or more of Y, M, and C are used more than K in full-color image printing. In this case, when this process is executed, deterioration of the cleaning blade can be suppressed.

  The print control unit 18 executes the processes of the following steps 31 to 52 for the printing process including the toner density correction process. In this process, during printing on the paper, the first cleaning blade 49 is in contact with the direct transfer belt 46 and the second cleaning blade 53 is in contact with the intermediate transfer belt 50, respectively. The belt surface is cleaned by the conveyance movement of the direct transfer belt 46 and the intermediate transfer belt 50.

(Step (indicated by “S” in the figure) 31)
The print control unit 18 determines whether or not the cumulative number of printed sheets exceeds 500 during printing of a full-color image on a sheet. If not, the toner density correction process is not performed, and the process of step 31 is performed. The determination process is repeated and the printing process is continued.

If it is determined that the number of printed sheets exceeds 500, it is determined that toner density correction processing is to be performed, and the process proceeds to step 32.
As described above, the toner density correction process is performed every time the number of printed sheets exceeds 500, thereby maintaining the image quality of printing by setting the toner density to the correct density.

(Step 32)
The print control unit 18 accesses the measurement unit 17, reads the accumulated contact time of the second cleaning blade 53 stored in the measurement unit 17, and the time during which the second cleaning blade 53 is in contact with the intermediate transfer belt 50. It is determined whether or not the cumulative contact time exceeds a preset 60 min. If it is determined that the cumulative contact time has exceeded, the process proceeds to step 33. If it is determined that the cumulative contact time has not exceeded, the process proceeds to step 44.
The cumulative contact time is a count value of an index for estimating the deterioration state of the second cleaning blade 53. For example, 60 minutes is set as a time when it is confirmed in advance that the deterioration has progressed through experiments.

(Step 33)
The printing control unit 18 controls the secondary transfer control unit 14 and the cleaning control unit 16, and the secondary transfer control unit 14 keeps the direct transfer belt 46 and the intermediate transfer belt 50 close to each other, and the cleaning control unit 16. Controls a portion including a motor, a clutch, and a solenoid for moving the second cleaning blade 53 of the cleaning unit 10, and moves the second cleaning blade 53 in the direction indicated by arrow D ′ in FIG. The second cleaning blade 53 is separated and the process proceeds to step 34.

(Step 34)
The print control unit 18 controls the secondary transfer control unit 14 and the cleaning control unit 16, and the secondary transfer control unit 14 brings the direct transfer belt 46 and the intermediate transfer belt 50 close to each other (the state shown in FIG. 11). The cleaning control unit 16 controls the portion of the cleaning unit 10 including the motor, clutch, and solenoid that moves the first cleaning blade 49, and moves the first cleaning blade 49 in the direction indicated by arrow C in FIG. Then, the first cleaning blade 49 is brought into contact with the transfer belt 46 directly, and the process proceeds to step 35.

(Step 35)
The printing control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 charges the secondary transfer bias unit 47 in a direction in which the toner image on the intermediate transfer belt 50 is directly transferred to the transfer belt 46. Apply a bias voltage for generating, and proceed to Step 36.

(Step 36)
The print control unit 18 controls the direct transfer control unit 12, and the direct transfer control unit 12 forms a K-color density correction toner pattern image on the photoconductor 40 and moves directly from the rotating photoconductor 40. The toner pattern image for K-color density correction (67 in FIG. 11) is transferred to the point of the transfer roller 44, and the process proceeds to step 37.

(Step 37)
The print control unit 18 controls the indirect transfer control unit 13, and the indirect transfer control unit 13 forms Y to C density correction toner pattern images on the photoconductors 41 to 43, respectively, and rotates the photoconductor 41. The toner pattern images (68 in FIG. 11) for Y to C are transferred to the intermediate transfer belt 50 moving from .about.43, and the process proceeds to step 38.

The Y-color to C-color density correction toner pattern images 68 on the intermediate transfer belt 50 are directly transferred onto the transfer belt 46 by the charges generated by the secondary transfer bias unit 47.
In FIG. 11, reference numerals 68, 68 ′, and 68 ″ denote three density correction toner pattern images of Y color to C color.

(Step 38)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the first toner pattern density detection sensor 48 of the sensor unit 9 for each of the K to C color correction toner pattern images. (67 ', 68' in FIG. 11) is detected, information for correcting the toner density of each color obtained by the detection is acquired, and the process proceeds to step 39.

(Step 39)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the information for correcting the toner densities of K to C obtained from the first toner pattern density detection sensor 48. Based on this, toner density correction processing for each color of black, yellow, magenta, and cyan is executed, and the process proceeds to step 40.

  The toner density correction processing for each color of black, yellow, magenta, and cyan adjusts charging, exposure, or development when forming toner images of each color of black, yellow, magenta, and cyan on the photoreceptors 40 to 43, respectively. Since this process is well known, detailed description thereof is omitted.

(Step 40)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 directly uses the first cleaning blade 49 of the cleaning unit 10 to directly print the density correction toner pattern images of K color to C color on the transfer belt 46 (see FIG. 11 ″, 67 ″, 68 ″) are collected, and the process proceeds to Step 41.

(Step 41)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 controls the part including the motor, the clutch, and the solenoid that moves the second cleaning blade 53 of the cleaning unit 10, and controls the second cleaning blade 53. The second cleaning blade 53 is brought into contact with the intermediate transfer belt 50 by moving in the direction indicated by the arrow D in FIG.

(Step 42)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 controls the part including the motor, the clutch, and the solenoid that moves the first cleaning blade 49 of the cleaning unit 10, and controls the first cleaning blade 49. The first cleaning blade 49 is moved away from the direct transfer belt 46 by moving in the direction indicated by the arrow C ′ in FIG.

(Step 43)
The print control unit 18 determines whether or not full-color image printing on the paper has been completed. If not, the process returns to step 31 and repeats the processes of steps 31 to 42. When the process is completed, the process ends.

  In the processing of steps 31 to 42, when the usage time of the second cleaning blade 53 becomes long, the first cleaning blade 49 is used to prevent early deterioration of the second cleaning blade 53.

(Step 44)
The printing control unit 18 controls the secondary transfer control unit 14 and the cleaning control unit 16, and the secondary transfer control unit 14 keeps the direct transfer belt 46 and the intermediate transfer belt 50 close to each other, and the cleaning control unit 16. The second cleaning blade 53 is kept in contact with the intermediate transfer belt 50 (the state shown in FIG. 12), and the process proceeds to step 45.

(Step 45)
The print control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 directly brings the first cleaning blade 49 away from the transfer belt 46 (the state shown in FIG. 12), and proceeds to step 46.

(Step 46)
The print control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 charges the toner image on the transfer belt 46 directly to the intermediate transfer belt 50 with respect to the secondary transfer bias unit 47. Apply a bias voltage for generating, and go to step 47.

(Step 47)
The print control unit 18 controls the direct transfer control unit 12, and the direct transfer control unit 12 forms a K-color density correction toner pattern image on the photoconductor 40 and moves directly from the rotating photoconductor 40. The toner pattern image for density correction of K color (69 in FIG. 12) is transferred to the point of the transfer roller 44, and the process proceeds to step 48.
The K color density correction toner pattern image 69 on the direct transfer belt 46 is transferred onto the intermediate transfer belt 50 by the electric charges generated by the secondary transfer bias unit 47.

(Step 48)
The print control unit 18 controls the indirect transfer control unit 13, and the indirect transfer control unit 13 forms Y to C density correction toner pattern images on the photoconductors 41 to 43, respectively, and rotates the photoconductor 41. The toner pattern images (70 in FIG. 12) for Y to C are transferred to the intermediate transfer belt 50 moving from .about.
In FIG. 12, reference numerals 70, 70 ′, and 70 ″ denote three density correction toner pattern images of Y color to C color.

(Step 49)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the second toner pattern density detection sensor 52 of the sensor unit 9 to perform each of the K to C color correction toner pattern images. (69 ', 70' in FIG. 12) is detected, information for correcting the toner densities of K to C obtained by the detection is acquired, and the process proceeds to step 50.

(Step 50)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the information for correcting the toner densities of K to C obtained from the second toner pattern density detection sensor 52. Based on this, toner density correction processing for each color of black, yellow, magenta, and cyan is executed, and the process proceeds to step 51.

  The toner density correction processing for each color of black, yellow, magenta, and cyan adjusts charging, exposure, or development when forming toner images of each color of black, yellow, magenta, and cyan on the photoreceptors 40 to 43, respectively. Since this process is well known, detailed description thereof is omitted.

(Step 51)
The print control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 uses the second cleaning blade 53 of the cleaning unit 10 to each K-C color density correction toner pattern image on the intermediate transfer belt 50 (see FIG. 12 of 69 ″, 70 ″) are collected, and the process proceeds to Step 52.

(Step 52)
The printing control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 charges the secondary transfer bias unit 47 in a direction in which the toner image on the intermediate transfer belt 50 is directly transferred to the transfer belt 46. Apply a bias voltage for generating, and go to step 43.
The processing in steps 44 to 52 is control when the usage time of the second cleaning blade 53 does not exceed the reference time.

  In the above-described processing, the deterioration state of the second cleaning blade 53 is detected based on the contact time between the second cleaning blade 53 and the intermediate transfer belt 50, and the accumulated contact time exceeds a certain threshold value (60 minutes in this embodiment). Therefore, it is considered that the deterioration of the second cleaning blade 53 has progressed.

In this case, each of the K-color to C-color density correction toner pattern images is directly detected by the first toner pattern density detection sensor 48 installed on the transfer belt 46.
Thereby, the contact time between the intermediate transfer belt 50 and the second cleaning blade 53 can be reduced, and the life of the second cleaning blade 53 can be further extended.

At the end of toner density adjustment, the second cleaning blade 53 may be brought into contact, the first cleaning blade 49 may be separated, and the state at the time of printing may be returned.
In the case of this control, the print control unit 18 operates with the functions (2) and (3) enabled.
Furthermore, the above control may be applied to the case where Y, M, and C color density correction is independently performed on the indirect transfer side during monochrome printing using only the direct transfer method.

  In the above-described processing, the cumulative contact time of the first cleaning blade 49 is also checked, and if it exceeds 60 minutes, a message that informs that the cleaning blade is exhausted and recommends maintenance is displayed on the operation display unit 11. It is good to do so.

Next, another example of the toner density correction process at the time of printing in the print control unit 18 shown in FIG. 1 will be described.
FIG. 13 is a flowchart showing still another processing example of the toner density correction processing at the time of printing in the print control unit 18 shown in FIG.
This processing is processing when the function (5) is validated by the print control unit 18.

  The print control unit 18 executes the processes of the following steps 61 to 82 for the print process including the toner density correction process. In this process, during printing on the paper, the first cleaning blade 49 is in contact with the direct transfer belt 46 and the second cleaning blade 53 is in contact with the intermediate transfer belt 50, respectively. The belt surface is cleaned by the conveyance movement of the direct transfer belt 46 and the intermediate transfer belt 50.

(Step (indicated by “S” in the figure) 61)
The print control unit 18 determines whether or not the cumulative number of prints exceeds 500 during printing of a full-color image on a sheet. If not, the toner density correction process is not performed, and the process of step 61 is performed. The determination process is repeated and the printing process is continued.

If it is determined that the number of printed sheets exceeds 500, it is determined that toner density correction processing is to be performed, and the process proceeds to step 62.
As described above, the toner density correction process is performed every time the number of printed sheets exceeds 500, thereby maintaining the image quality of printing by setting the toner density to the correct density.

(Step 62)
The print control unit 18 accesses the measurement unit 17, reads the accumulated contact time 1 of the first cleaning blade 49 and the accumulated contact time 2 of the second cleaning blade 53 stored in the measurement unit 17, and accumulates the contact time 1. Is determined to exceed the cumulative contact time 2, and if it is determined that it has exceeded, it can be presumed that the deterioration of the first cleaning blade 49 has progressed. If the determination is made, it can be estimated that the deterioration of the second cleaning blade 53 is progressing, so the routine proceeds to step 73.

  If the accumulated contact time 1 exceeds the accumulated contact time 2 in the above determination, it can be estimated that the deterioration of the first cleaning blade 49 is progressing, so the intermediate transfer belt 50 is processed in steps 63 to 71. When the toner density correction for each of the colors K to C using the toner is performed, and the cumulative contact time 1 does not exceed the cumulative contact time 2, the deterioration of the second cleaning blade 53 is more advanced. Therefore, the toner density correction for each of the colors K to C using the transfer belt 46 directly is performed in the processing of steps 73 to 82.

  In this way, if one cleaning blade has been used for a long time enough to cause a deterioration that would lead to a decrease in cleaning performance, the other cleaning will not cause a decrease in cleaning performance if the usage time is relatively short. Since the transfer destination of the density correction toner pattern image is switched so as to use the blade, it is possible to avoid a situation in which the toner image cannot be collected cleanly from the transfer belt due to the deterioration of the cleaning blade.

(Step 63)
The printing control unit 18 controls the secondary transfer control unit 14 and the cleaning control unit 16, and the secondary transfer control unit 14 keeps the direct transfer belt 46 and the intermediate transfer belt 50 close to each other, and the cleaning control unit 16. Will leave the first cleaning blade 49 directly away from the transfer belt 46 and proceed to step 64.

(Step 64)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 keeps the second cleaning blade 53 in contact with the intermediate transfer belt 50, and proceeds to step 65.

(Step 65)
The print control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 charges the toner image on the transfer belt 46 directly to the intermediate transfer belt 50 with respect to the secondary transfer bias unit 47. Apply a bias voltage for generating, and proceed to Step 66.

(Step 66)
The print control unit 18 controls the direct transfer control unit 12, and the direct transfer control unit 12 forms a K-color density correction toner pattern image on the photoconductor 40 and moves directly from the rotating photoconductor 40. The toner pattern image of K color density correction is transferred to the point of the transfer roller 44, and the process proceeds to Step 67.
The K color density correction toner pattern image on the direct transfer belt 46 is transferred onto the intermediate transfer belt 50 by the charge generated by the secondary transfer bias unit 47.

(Step 67)
The print control unit 18 controls the indirect transfer control unit 13, and the indirect transfer control unit 13 forms Y to C density correction toner pattern images on the photoconductors 41 to 43, respectively, and rotates the photoconductor 41. Each of the Y-color to C-color density correction toner pattern images is transferred to the intermediate transfer belt 50 moving from .about.43, and the process proceeds to step 68.

(Step 68)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the second toner pattern density detection sensor 52 of the sensor unit 9 to perform each of the K to C color correction toner pattern images. , And information for correcting the toner densities of K to C obtained by the detection is acquired.

(Step 69)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the information for correcting the toner densities of K to C obtained from the second toner pattern density detection sensor 52. Based on this, toner density correction processing for each color of black, yellow, magenta, and cyan is executed, and the process proceeds to step 70.

  The toner density correction processing for each color of black, yellow, magenta, and cyan adjusts charging, exposure, or development when forming toner images of each color of black, yellow, magenta, and cyan on the photoreceptors 40 to 43, respectively. Since this process is well known, detailed description thereof is omitted.

(Step 70)
The print control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 collects the K-color to C-color density correction toner pattern images on the intermediate transfer belt 50 by the second cleaning blade 53 of the cleaning unit 10. Then, the process proceeds to Step 71.

(Step 71)
The printing control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 charges the secondary transfer bias unit 47 in a direction in which the toner image on the intermediate transfer belt 50 is directly transferred to the transfer belt 46. Apply a bias voltage for generating, and go to step 72.

  The processing in steps 63 to 71 is control when the usage time of the first cleaning blade 49 is longer than that of the second cleaning blade 53 (when deterioration of the cleaning performance of the first cleaning blade 49 is suspected).

(Step 72)
The print control unit 18 determines whether or not full-color image printing on the paper has been completed. If not, the process returns to step 61 and repeats the processing of steps 61 to 71. When the printing is completed, the processing ends.

(Step 73)
The printing control unit 18 controls the secondary transfer control unit 14 and the cleaning control unit 16, and the secondary transfer control unit 14 keeps the direct transfer belt 46 and the intermediate transfer belt 50 close to each other, and the cleaning control unit 16. Controls a portion including a motor, a clutch, and a solenoid that moves the second cleaning blade 53 of the cleaning unit 10, moves the second cleaning blade 53, and separates the second cleaning blade 53 from the intermediate transfer belt 50, Proceed to step 74.

(Step 74)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 controls the part including the motor, the clutch, and the solenoid that moves the first cleaning blade 49 of the cleaning unit 10, and controls the first cleaning blade 49. The first cleaning blade 49 is brought into contact with the transfer belt 46 directly, and the process proceeds to step 75.

(Step 75)
The printing control unit 18 controls the secondary transfer control unit 14, and the secondary transfer control unit 14 charges the secondary transfer bias unit 47 in a direction in which the toner image on the intermediate transfer belt 50 is directly transferred to the transfer belt 46. Apply a bias voltage for generating, and go to step 76.

(Step 76)
The print control unit 18 controls the direct transfer control unit 12, and the direct transfer control unit 12 forms a K-color density correction toner pattern image on the photoconductor 40 and moves directly from the rotating photoconductor 40. Then, the toner pattern image for K color density correction is transferred to the point of the transfer roller 44, and the process proceeds to Step 77.

(Step 77)
The print control unit 18 controls the indirect transfer control unit 13, and the indirect transfer control unit 13 forms Y to C density correction toner pattern images on the photoconductors 41 to 43, respectively, and rotates the photoconductor 41. Each of the Y-color to C-color density correction toner pattern images is transferred to the intermediate transfer belt 50 moving from .about.43, and the process proceeds to step 78.
The Y-color to C-color density correction toner pattern images on the intermediate transfer belt 50 are directly transferred onto the transfer belt 46 by the charges generated by the secondary transfer bias unit 47.

(Step 78)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the first toner pattern density detection sensor 48 of the sensor unit 9 for each of the K to C color correction toner pattern images. , And obtains information for correcting the toner density of each color obtained by the detection, and proceeds to step 79.

(Step 79)
The print control unit 18 controls the toner density correction control unit 15, and the toner density correction control unit 15 uses the information for correcting the toner densities of K to C obtained from the first toner pattern density detection sensor 48. Based on this, toner density correction processing for each color of black, yellow, magenta, and cyan is executed, and the process proceeds to step 80.
The toner density correction processing for each color of black, yellow, magenta, and cyan adjusts charging, exposure, or development when forming toner images of each color of black, yellow, magenta, and cyan on the photoreceptors 40 to 43, respectively. Since this process is well known, detailed description thereof is omitted.

(Step 80)
The print control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 directly collects the K-color to C-color density correction toner pattern images on the transfer belt 46 by the first cleaning blade 49 of the cleaning unit 10. Then, the process proceeds to Step 81.

(Step 81)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 controls the part including the motor, the clutch, and the solenoid that moves the first cleaning blade 49 of the cleaning unit 10, and controls the first cleaning blade 49. The first cleaning blade 49 is moved away from the direct transfer belt 46 to proceed to step 82.

(Step 82)
The printing control unit 18 controls the cleaning control unit 16, and the cleaning control unit 16 controls the part including the motor, the clutch, and the solenoid that moves the second cleaning blade 53 of the cleaning unit 10, and controls the second cleaning blade 53. Then, the second cleaning blade 53 is brought into contact with the intermediate transfer belt 50, and the process proceeds to Step 72.

In this way, the usage time of the first cleaning blade 49 and the second cleaning blade 53 can be averaged, and as a result, the life of the cleaning performance of the entire image forming apparatus is extended.
Further, since cleaning can be performed with a cleaning blade that is always in a good state (higher cleaning performance), image deterioration due to remaining toner on the belt can be suppressed.

At the end of toner density adjustment, the second cleaning blade 53 may be brought into contact, the first cleaning blade 49 may be separated, and the state at the time of printing may be returned.
In the case of this control, the print control unit 18 operates with the functions (2) and (3) enabled.

FIG. 14 is a diagram showing an example of a setting screen for setting the presence / absence of execution of the toner density correction process at the time of printing and the threshold value of the accumulated contact time.
An operation panel as shown in FIG. 14 is displayed on the operation display unit 11 under the control of the print control unit 18.

  This operation panel is set to ON / OFF (ON / OFF) for setting whether or not to execute the toner density correction control at the time of printing described above, and a threshold value for comparing the accumulated contact times 1 and 2 (in the above processing, The user can arbitrarily set the preset 60 min case). The set contents are stored in a non-volatile memory, for example, the ROM 25 or the RAM 26 in FIG. 2, and are read and used by the print control unit 18 when the image forming apparatus is turned on.

  The image forming apparatus and program according to the present invention can be applied to all image forming apparatuses including facsimile machines, printers, copiers, and multifunction machines.

1: Printer unit 2: K image forming unit 3: Y image forming unit 4: M image forming unit 5: C image forming unit 6: Direct transfer unit 7: Indirect transfer unit 8: Secondary transfer unit 9: Sensor unit 10: Cleaning unit 11: Operation display unit 12: Direct transfer control unit 13: Indirect transfer control unit 14: Secondary transfer control unit 15: Toner density correction control unit 16: Cleaning control unit 17: Measurement unit 18: Print control unit 20: Controller DESCRIPTION OF SYMBOLS 21, 22: Motor 23: Each load part 24: CPU 25: ROM 26: RAM 27: Direct transfer drive motor I / F part 28, 30: Driver 29: Indirect transfer drive motor I / F part 31: I / O control Sections 40 to 43: Photoconductor 44: Transfer roller 45: Conveying roller 46: Direct transfer belt 47: Secondary transfer by Scan unit 48: first toner pattern density detection sensor 49: first cleaning blade 50: intermediate transfer belt 51: the secondary transfer roller 52: second toner pattern density detection sensor 53: second cleaning blade

JP 2010-092013 A

Claims (7)

First transfer means for transferring a toner image to a first transfer member or transfer paper conveyed by the first transfer member;
A second transfer means for transferring a toner image different from the toner image transferred to the second transfer body by the first transfer means;
An approaching / separating means for approaching and separating the first transfer body and the second transfer body;
When the first transfer member and the second transfer member are brought close to each other by the approaching / separating means, the toner image of the first transfer member is transferred to the second transfer member or the toner image of the second transfer member is transferred to the second transfer member. A secondary transfer means for transferring to the first transfer body;
First density detecting means for detecting the density of the toner image on the first transfer member;
Second density detecting means for detecting the density of the toner image on the second transfer member;
First collecting means for collecting the toner image of the first transfer member;
A second collecting means for collecting the toner image of the second transfer member;
Abutting / separating means for bringing the first collecting means into contact with or separating from the first transfer body, and bringing the second collecting means into contact with or separating from the second transfer body;
First deterioration measuring means for measuring a count value of an index for estimating the deterioration state of the first recovery means;
When correcting the density of the toner image transferred to the first transfer body, when it is determined that the count value of the first deterioration measuring means exceeds a reference value, the approaching / separating means causes the first transfer body and the first transfer body to be corrected. The second transfer member is brought close to the first transfer member, and the second recovery member is brought into contact with the second transfer member. An image forming apparatus comprising: control means for detecting a toner image for toner density correction from the second transfer member.   When the toner image is transferred by the first transfer unit or the secondary transfer unit to the transfer paper conveyed by the first transfer member, the control unit causes the contact / separation unit to remove the toner image from the first transfer member. The image forming apparatus according to claim 1, further comprising: a unit that executes control to place the one collecting unit in a separated state.   The control means executes control to bring the first collection means into contact with the first transfer body by the contact / separation means only when collecting the density correction toner image from the first transfer body. The image forming apparatus according to claim 1, further comprising a unit. The image forming apparatus according to claim 1.
Providing a second deterioration measuring means for measuring a count value of an index for estimating the deterioration state of the second recovery means;
When the control means corrects the toner image density transferred to the first transfer body and the toner image density transferred to the second transfer body, the count value of the second deterioration measurement means exceeds a reference value. When the determination is made, the first transfer member and the second transfer member are brought closer to each other by the approaching / separating unit, the first recovery unit is brought into contact with the first transfer member by the contact / separation unit, and the second transfer is performed. An image forming apparatus comprising: means for separating the second collecting means from the body, and causing the first density detecting means to detect a toner image for toner density correction from the first transfer body. First transfer means for transferring a toner image to a first transfer member or transfer paper conveyed by the first transfer member;
A second transfer means for transferring a toner image different from the toner image transferred to the second transfer body by the first transfer means;
An approaching / separating means for approaching and separating the first transfer body and the second transfer body;
When the first transfer member and the second transfer member are brought close to each other by the approaching / separating means, the toner image of the first transfer member is transferred to the second transfer member or the toner image of the second transfer member is transferred to the second transfer member. A secondary transfer means for transferring to the first transfer body;
First density detecting means for detecting the density of the toner image on the first transfer member;
Second density detecting means for detecting the density of the toner image on the second transfer member;
First collecting means for collecting the toner image of the first transfer member;
A second collecting means for collecting the toner image of the second transfer member;
Abutting / separating means for bringing the first collecting means into contact with or separating from the first transfer body, and bringing the second collecting means into contact with or separating from the second transfer body;
First deterioration measuring means for measuring a count value of an index for estimating the deterioration state of the first recovery means;
Second deterioration measuring means for measuring a count value of an index for estimating the deterioration state of the second recovery means;
(A) When correcting the density of the toner image transferred to the first transfer body, (a-1) determining that the count value of the first deterioration measurement means exceeds the count value of the second deterioration measurement means. Sometimes, the approaching / separating means causes the first transfer body and the second transfer body to approach each other, the contact / separation means causes the first transfer body to be separated from the first transfer body, and the second transfer body is moved to the second transfer body. The second collection unit is brought into contact, and the second density detection unit is controlled to detect a toner image for toner density correction from the second transfer member, and (a-2) of the first deterioration measurement unit When it is determined that the count value does not exceed the count value of the second deterioration measuring unit, the first transfer member and the second transfer member are separated by the approaching / separating unit, and the first separation member is separated by the contact / separation unit. The first collecting hand on one transfer body And a control for causing the first density detecting means to detect a toner image for correcting the toner density from the first transfer body, and causing the first density detecting means to detect a toner image for correcting the toner density from the second transfer body. b) When correcting the toner image density transferred to the first transfer body and the toner image density transferred to the second transfer body, (b-1) the count value of the first deterioration measuring means is the second deterioration measurement When it is determined that the count value of the means exceeds the first transfer body, the first transfer body and the second transfer body are brought closer to each other by the approaching / separating means, and the first recovery body is removed from the first transfer body by the contact / separation means. And a control for separating the means and bringing the second recovery means into contact with the second transfer body and causing the second density detection means to detect a toner image for toner density correction from the first transfer body, b-2) The first deterioration When it is determined that the count value of the measuring means does not exceed the count value of the second deterioration measuring means, the approaching / separating means causes the first transfer body and the second transfer body to approach each other, and the contact / separation means The first collection unit is brought into contact with the first transfer body and the second collection unit is separated from the second transfer body, and the first density detection unit is configured to correct toner density from the first transfer body. An image forming apparatus comprising: control means for executing control for detecting a toner image.   6. The image forming apparatus according to claim 1, further comprising a setting unit configured to set whether to enable the control unit.   A first transfer unit that transfers a toner image to a first transfer member or transfer paper conveyed by the first transfer member, and a toner image that is different from the toner image transferred by the first transfer unit to a second transfer member The second transfer means, the approaching / separating means for approaching and separating the first transfer body and the second transfer body, and the approaching / separating means approaching the first transfer body and the second transfer body. A second transfer unit that transfers the toner image of the first transfer member to the second transfer member or the toner image of the second transfer member to the first transfer member; and the toner image of the first transfer member. A first density detecting means for detecting the density of the toner image, a second density detecting means for detecting the density of the toner image on the second transfer body, a first collecting means for collecting the toner image on the first transfer body, Collect the toner image of the second transfer member 2 collecting means, and a contacting / separating means for bringing the first collecting means into contact with or separating from the first transfer body, and bringing the second collecting means into contact with or separating from the second transfer body; A first deterioration measuring means for measuring a count value of an index for estimating the deterioration state of the first recovery means; and a second deterioration measuring means for measuring a count value of an index for estimating the deterioration state of the second recovery means. A program comprising a procedure for causing a computer that controls an image forming apparatus provided to function as the image forming apparatus according to any one of claims 1 to 6.

Images