JP2021184051A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can exhibit satisfactory toner transfer performance even on embossed paper.SOLUTION: An image forming apparatus comprises: an image carrier that can carry a toner image; a lubricant supply unit that supplies lubricant onto the image carrier; a control unit that reduces the amount of the lubricant on the image carrier compared with a case in which before a toner image is formed on embossed paper, a toner image is formed on a recording medium other than the embossed paper with the use of the image carrier; and a cleaning unit that removes the lubricant on the image carrier. After an operation to correct the performance related to image formation is executed in the image forming apparatus, the control unit causes the cleaning unit to remove the lubricant on the image carrier.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus.

An electrophotographic image forming apparatus (printer, copier, facsimile, multifunction device, etc.) has a cleaning blade for removing residual toner remaining on an image carrier such as a photoconductor drum or an intermediate transfer belt. The device is equipped. Further, in order to reduce the frictional force between the image carrier and the cleaning blade and smoothly clean the residual toner on the image carrier, a lubricant supply device for supplying a lubricant as a lubricant is provided on the image carrier. Some (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-8276

In the image forming apparatus having the lubricant supply device described above, no deterioration in transferability is observed in plain paper other than uneven paper even if the amount of lubricant on the image carrier is increased. However, it has been newly found that when an image is formed on uneven paper having unevenness such as embossed paper, if the amount of lubricant on the image carrier is large, the transferability of the toner image to the uneven paper deteriorates.

Specifically, the present inventor measures the pure water contact angle as a substitute for the lubricant amount because the pure water contact angle on the intermediate transfer belt increases as the amount of lubricant on the intermediate transfer belt increases. The transferability to embossed paper with respect to the water contact angle was evaluated. FIG. 1 is a graph for evaluating the transferability to embossed paper with respect to the pure water contact angle on the intermediate transfer belt. In FIG. 1, the transferability is evaluated by the transferability ranks of 1 to 5, and the larger the number of the transferability rank, the better the transferability. As shown in FIG. 1, in the case of embossed paper, when the pure water contact angle becomes large, that is, when the amount of lubricant increases, the transferability deteriorates.

This tendency can also be confirmed from the presence / absence and type of correction operation in the image forming apparatus. The correction operation is performed to correct the performance related to image formation. FIG. 2 is a graph for evaluating the transferability to embossed paper with respect to the presence / absence of correction operation and the type of correction operation. Also in FIG. 2, the transferability is evaluated with a transferability rank of 1 to 5. In FIG. 2, “No correction operation” is a transferability rank on the embossed paper when an image is formed by passing one sheet of embossed paper without performing the correction operation, and is a transferability rank 4. In this case, since there is no correction operation, that is, there is no operation of transferring the lubricant on the intermediate transfer belt, the lubricant does not transfer on the intermediate transfer belt. Even if the lubricant may be transferred, the amount of the lubricant transferred on the intermediate transfer belt is small. Therefore, the transferability has not deteriorated.

On the other hand, in FIG. 2, the correction operations A to C are transferability ranks on the embossed paper when the correction operations A to C are performed and one sheet of embossed paper is passed to form an image. The correction operations A to C have a lower transferability rank than the case without the correction operation. This is because the correction operations A to C have an operation of transferring the lubricant on the intermediate transfer belt, so that the amount of the lubricant on the intermediate transfer belt is larger than that without the correction operation. Further, the transferability ranks of the correction operations A to C are correction operation A <correction operation B <correction operation C. In each of the correction operations A to C, the idle rotation times a to c in which the toner image is not formed on the intermediate transfer belt are a> b> c, and the transfer is performed in the correction operation A having the longest idle rotation time a. The gender rank is low. This is because when the idle rotation time becomes long, the operation time for the lubricant to be transferred onto the intermediate transfer belt becomes long, and the amount of the lubricant transferred to the intermediate transfer belt increases. Further, although the lubricant can be removed by the above-mentioned cleaning device during the idle rotation time, the toner image functioning as an abrasive is not transferred onto the intermediate transfer belt, so the effect of the removal is not great, and the amount of the lubricant to be removed is not great. This is because the amount of lubricant that transfers more is greater. As described above, it can be seen from FIG. 2 that in the embossed paper, the transferability deteriorates as the amount of lubricant on the intermediate transfer belt increases.

Here, in the embossed paper, the mechanism in which the transferability deteriorates when the amount of lubricant on the intermediate transfer belt increases will be described with reference to FIGS. 3A and 3B. FIG. 3A is a diagram illustrating transfer of a toner image to plain paper on an intermediate transfer belt. Further, FIG. 3B is a diagram illustrating the transfer of the toner image to the embossed paper on the intermediate transfer belt.

Lubricants are supplied to the intermediate transfer belt from the lubricant supply device via the photoconductor drum. The lubricant supplied to the intermediate transfer belt forms a lubricant layer on the intermediate transfer belt, as shown in FIGS. 3A and 3B. It is considered that the lubricant layer thus formed is deteriorated and deteriorated by the discharge product generated by the voltage applied during the primary transfer and the secondary transfer, thereby causing the resistance of the lubricant layer to be lowered.

When the secondary transfer is performed on the plain paper P0, even if the lubricant layer has a low resistance, the plain paper P0 has no unevenness (small), so that the electric charge generated by the applied voltage is not locally concentrated. .. As a result, a uniform electric field is formed on the plain paper P0, so that the transferability of the toner to the plain paper P0 becomes good.

On the other hand, when the secondary transfer is performed on the embossed paper P1, if the lubricant layer has a low resistance, the embossed paper P1 has irregularities (large), so that the electric charge generated by the applied voltage tends to concentrate on the convex portions. Become. As a result, on the embossed paper P1, an electric field is formed in the convex portion, but it becomes difficult to form an electric field in the concave portion, so that the transferability to the concave portion is particularly deteriorated. If the lubricant layer is thick, that is, if the amount of lubricant on the intermediate transfer belt is large, the resistance becomes lower and the transferability worsens.

As described above, when the amount of lubricant on the image carrier such as the intermediate transfer belt is large, the transferability of the toner to the uneven paper such as embossed paper is deteriorated.

An object of the present invention is to provide an image forming apparatus capable of improving the transferability of toner even with uneven paper.

The image forming apparatus according to the present invention is
An image carrier capable of supporting a toner image and an image carrier
A lubricant supply unit that supplies the lubricant onto the image carrier,
The lubricant on the image carrier is compared with the case where the toner image is formed on a recording medium other than the uneven paper before the toner image is formed on the uneven paper via the image carrier. A control unit that reduces the amount,
To prepare for.

According to the present invention, the transferability of toner can be improved even with uneven paper.

It is a graph which evaluated the transferability with uneven paper with respect to the pure water contact angle on an intermediate transfer belt. It is a graph which evaluated the transferability with uneven paper with respect to the presence / absence of a correction operation, and the type of a correction operation. It is a figure explaining the transfer of the toner image to the plain paper in the intermediate transfer belt. It is a figure explaining the transfer of the toner image to the uneven paper in the intermediate transfer belt. It is a figure which shows schematically the whole structure of the image forming apparatus which concerns on embodiment of this invention. It is a figure which shows the main part of the control system of the image forming apparatus which concerns on embodiment of this invention. It is a figure which shows the drum cleaning unit which has a lubricant supply part. It is a flowchart explaining an example of the lubricant reduction method carried out by the image forming apparatus shown in FIG. It is a graph which evaluated the transferability rank with uneven paper with respect to the toner feed amount to the cleaning part of the image forming apparatus shown in FIG. 4 and the idle rotation time of an intermediate transfer belt. It is a graph which evaluated the transferability rank in the uneven paper in the case where the lubricant removal operation is performed after the correction operation. It is a flowchart explaining another example (modification example 2) of the lubricant reducing method carried out by the image forming apparatus shown in FIG. It is a figure which shows the image pattern of the toner image in the correction operation of the toner density adjustment. It is a figure which shows an example (image pattern 1) of the image pattern of the toner image in the correction operation of the lubricant adhesion suppression. It is a figure which shows another example (image pattern 2) of the image pattern of the toner image in the correction operation of the lubricant adhesion suppression. It is a figure which shows another example (image pattern 3) of the image pattern of the toner image in the correction operation of the lubricant adhesion suppression. It is a figure which shows another example (image pattern 4) of the image pattern of the toner image in the correction operation of the lubricant adhesion suppression. It is a graph which evaluated the transferability rank in uneven paper when image patterns 1 to 3 were used in correction operation A. In the correction operation A2, it is a graph which evaluated the transferability rank with uneven paper with respect to the toner feed amount to the cleaning part of the image forming apparatus shown in FIG. 4 and the idle rotation time of an intermediate transfer belt. It is a graph which evaluated the transferability rank in the uneven paper in the case where the lubricant removal operation is performed after the correction operation A2 to A4. It is a figure explaining an example of the molecular structure of the coat layer in the intermediate transfer belt which has a coat layer. In the intermediate transfer belt having a coating layer is a graph showing the initial and NO ₃ detected amount after continuous 50,000 sheets processing.

Hereinafter, the image forming apparatus according to the embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 4 is a diagram schematically showing the overall configuration of the image forming apparatus 1 according to the present embodiment. FIG. 5 is a diagram showing a main part of the control system of the image forming apparatus 1 according to the present embodiment. The image forming apparatus 1 is an example of the present embodiment, and its configuration, specifications, and the like are not limited to the following description and can be appropriately changed.

As shown in FIG. 4, the image forming apparatus 1 is an intermediate transfer type color image forming apparatus using an electrophotographic process technique. That is, the image forming apparatus 1 primary transfers each color toner image of CMYK formed on the photoconductor to the intermediate transfer body, superimposes the toner images of four colors on the intermediate transfer body, and then forms a paper as a recording medium. An image is formed by secondary transfer to the toner. CMYK means C (cyan), M (magenta), Y (yellow), and K (black).

Further, the image forming apparatus 1 employs a tandem method in which photoconductors corresponding to the four colors of CMYK are arranged in series in the traveling direction of the intermediate transfer body, and the toner images of each color are sequentially transferred to the intermediate transfer body in one procedure. Has been done.

The image forming apparatus 1 shown in FIGS. 4 and 5 includes an image reading unit 10, an operation display unit 20, an image processing unit 30, an image forming unit 40, a paper transport unit 50, a fixing unit 60, a control unit 70, and the like.

The control unit 70 includes a CPU (Central Processing Unit) 71, a ROM (Read Only Memory) 72, a RAM (Random Access Memory) 73, and the like. The CPU 71 reads a program according to the processing content from the ROM 72, develops it in the RAM 73, and centrally controls the operation of each block of the image forming apparatus 1 in cooperation with the expanded program. At this time, various data such as a LUT (Look Up Table) stored in the storage unit 82 are referred to. The storage unit 82 is composed of, for example, a non-volatile semiconductor memory (so-called flash memory) or a hard disk drive.

The control unit 70 transmits / receives various data to / from an external device (for example, a personal computer) connected to a communication network such as a LAN (Local Area Network) or WAN (Wide Area Network) via the communication unit 81. I do. The control unit 70 receives, for example, image data transmitted from an external device, and forms an image on paper based on the image data (input image data). The communication unit 81 is composed of, for example, a communication control card such as a LAN card.

The image reading unit 10 includes an automatic document feeding device 11 called an ADF (Auto Document Feeder), a document image scanning device 12 (scanner), and the like.

The automatic document feeding device 11 conveys the document D placed on the document tray by the conveying mechanism and sends it out to the document image scanning device 12. The automatic document feeding device 11 can continuously read a large number of images (including both sides) of documents D placed on the document tray at once.

The document image scanning device 12 optically scans the document conveyed on the contact glass from the automatic document feeding device 11 or the document placed on the contact glass, and the reflected light from the document is a CCD (Charge Coupled Device). ) An image is formed on the sensor 12a and the original image is read. The image reading unit 10 generates input image data based on the reading result of the original image scanning device 12. Predetermined image processing is performed on the input image data by the image processing unit 30.

The operation display unit 20 is composed of, for example, a liquid crystal display (LCD: Liquid Crystal Display) with a touch panel, and functions as a display unit 21 and an operation unit 22. The display unit 21 displays various operation screens, an image status display, an operation status of each function, and the like according to a display control signal input from the control unit 70. The operation unit 22 includes various operation keys such as a numeric keypad and a start key, receives various input operations by the user, and outputs an operation signal to the control unit 70.

The image processing unit 30 includes a circuit that performs image processing according to initial settings or user settings for the input image data. The image forming unit 40 is controlled based on the image data that has undergone image processing.

The image forming unit 40 is an image forming unit 41Y, 41M, 41C, 41K for forming an image with each colored toner of Y component, M component, C component, and K component based on the image data from the image processing unit 30. , An intermediate transfer unit 42 and the like.

The image forming units 41Y, 41M, 41C, 41K for the Y component, the M component, the C component, and the K component have the same configuration. Therefore, in FIG. 4, reference numerals are given only to the components of the image forming unit 41Y for the Y component, and the reference numerals are omitted for the components of the other image forming units 41M, 41C, and 41K.

The image forming unit 41 includes an exposure device 411, a developing device 412, a photoconductor drum 413 (image carrier), a charging device 414, a drum cleaning unit (hereinafter, cleaning unit) 415, and the like.

The exposure apparatus 411 is composed of, for example, a semiconductor laser, and irradiates the photoconductor drum 413 with a laser beam corresponding to an image of each color component. When positive charges are generated in the charge generation layer of the photoconductor drum 413 by irradiation with laser light and transported to the surface of the charge transport layer, the surface charge (negative charge) of the photoconductor drum 413 is neutralized. As a result, an electrostatic latent image of each color component is formed on the surface of the photoconductor drum 413 due to the potential difference from the surroundings.

The developing device 412 is a two-component developing system developing device having, for example, a developing sleeve 412A, and visualizes an electrostatic latent image by adhering toner of each color component from the developing sleeve 412A to the surface of the photoconductor drum 413. To form a toner image.

The photoconductor drum 413 is, for example, a conductive cylinder (aluminum tube) made of aluminum, an undercoat layer (UCL: Under Coat Layer), a charge generation layer (CGL: Charge Generation Layer), and a charge transport layer (CTL: Charge). Transport Layer) etc. are provided. The photoconductor drum 413 is a photoconductor having photoconductivity, which is formed by sequentially laminating an undercoat layer, a charge generation layer, and a charge transport layer on the peripheral surface of a conductive cylinder, and is, for example, a negatively charged type. Organic Photo-conductor (OPC). The photoconductor drum 413 is rotated at a constant peripheral speed (linear speed) by controlling the drive current supplied to the drive motor (not shown) by the control unit 70.

The charging device 414 uniformly charges the surface of the photoconductor drum 413 having photoconductivity to a negative electrode property.

The cleaning unit 415 will be described with reference to FIG. FIG. 6 is a diagram showing a cleaning unit 415 having a lubricant supply unit 450. The cleaning unit 415 includes a drum cleaning blade (hereinafter, cleaning blade) 416, a lubricant supply unit 450, and the like. These are attached to the support frame body 415a.

The cleaning blade 416 (cleaning unit) is slidably contacted with the surface of the photoconductor drum 413 to remove the transfer residual toner remaining on the surface of the photoconductor drum 413 after the primary transfer. The cleaning blade 416 is formed by molding an elastic member such as urethane rubber into a flat plate-shaped sheet, and has a width substantially equal to the width in the axial direction (main scanning direction) of the photoconductor drum 413. Here, the cleaning blade 416 has a counter-type configuration in which the tip (edge) thereof is brought into contact with the photoconductor drum 413 so as to face the rotation direction R1. Specifically, with a predetermined contact angle and penetration amount from the counter direction (the direction in which the tip portion of the cleaning blade 416 is stretched when the photoconductor drum 413 rotates) with respect to the rotation direction R1 of the photoconductor drum 413. It is arranged so as to be in contact with each other.

The lubricant supply unit 450 includes a brush 451 and a lubricant 452, a pressing member 453, a support sheet metal 454, and the like. The lubricant 452 is formed by solidifying the lubricant. The brush 451 and the lubricant 452 are supported by the support sheet metal 454 and are fixed to the support frame body 415a via the pressing member 453. The pressing member 453 is, for example, a compression spring, and in order to keep the lubricant 452 in contact with the brush 451, the lubricant 452 is pressed toward the brush 451 with a predetermined pressing load. The width of the lubricant 452 is narrower than the width of the cleaning blade 416. The lubricant 452 has, for example, a pencil hardness equivalent to F to HB. The lubricant used in the lubricant 452 is, for example, zinc stearate (ZnSt).

The brush 451 has a role of supplying the lubricant 452 onto the photoconductor drum 413. The brush 451 is a roller-shaped brush in which a base cloth in which fibers such as polyester are planted is wound around a core metal, and has a width substantially equal to the axial width of the photoconductor drum 413. The brush 451 is arranged so as to be in contact with the surface of the lubricant 452 and the surface of the photoconductor drum 413, and is rotated in the rotation direction R2 opposite to the rotation direction R1 of the photoconductor drum 413 to be placed on the photoconductor drum 413. Supply lubricant.

As shown in FIG. 4, the intermediate transfer unit 42 includes an intermediate transfer belt 421, a plurality of support rollers 423, a secondary transfer roller 424, a main cleaner 426, a sub cleaner 427, and the like. The plurality of support rollers 423 include rollers such as a drive roller 423A and a backup roller 423B.

The intermediate transfer belt 421 (image carrier) is stretched in a loop on a plurality of support rollers 423, and the drive roller 423A rotates, so that the intermediate transfer belt 421 travels at a constant speed in the direction of arrow A. The primary transfer roller 422 presses the intermediate transfer belt 421 against the photoconductor drum 413, whereby the toner image is transferred from the photoconductor drum 413 to the intermediate transfer belt 421. The secondary transfer roller 424 is pressed against the backup roller 423B with the intermediate transfer belt 421 interposed therebetween, thereby transferring the toner image from the intermediate transfer belt 421 to the paper P. The paper P on which the toner image is transferred is conveyed toward the fixing portion 60. Instead of the secondary transfer roller 424, a belt-type secondary transfer unit in which a secondary transfer belt is stretched in a loop on a plurality of support rollers may be adopted.

Here, the intermediate transfer belt 421 has at least two layers, a base material layer and a surface layer arranged on the base material layer. For the base material layer, for example, a polyimide (PI) resin or the like is used. The base material layer may have a single layer structure or a plurality of layers. Further, for the surface layer, for example, _{a material containing silicon dioxide (SiO 2} ) as a main component is used. That is, the intermediate transfer belt 421 is configured by applying a coat layer containing _{glass (SiO 2) as a main component.} The surface roughness of the intermediate transfer belt 421 is a ten-point average roughness Rzjis = 0.75 μm.

The main cleaner 426 (cleaning portion) is arranged on the upstream side of the sub cleaner 427 in the rotation direction A of the intermediate transfer belt 421. The main cleaner 426 includes a cleaning blade, a support frame, and the like that slide in contact with the surface of the intermediate transfer belt 421 that rotates and moves in the rotation direction A to remove foreign matter.

The cleaning blade of the main cleaner 426 is a member that removes toner, lubricant, and the like adhering to the surface of the intermediate transfer belt 421. The cleaning blade has the tip (edge) of the cleaning blade in contact with the surface of the intermediate transfer belt 421 in the counter direction with respect to the rotation direction A of the intermediate transfer belt 421. The material of the cleaning blade is, for example, urethane rubber, but any other elastic material may be used.

The sub-cleaner 427 (cleaning unit) is arranged adjacent to the main cleaner 426 on the downstream side in the rotation direction A of the intermediate transfer belt 421. The sub-cleaner 427 is provided with a scraper, a support frame, and the like on the downstream side of the main cleaner 426, which are in sliding contact with the surface of the intermediate transfer belt 421 to remove foreign matter.

The scraper of the sub-cleaner 427 is a member that removes toner, lubricant, etc. adhering to the surface of the intermediate transfer belt 421 that could not be completely removed by the main cleaner 426. In this scraper, the tip (edge) of the scraper is brought into contact with the surface of the intermediate transfer belt 421 in the counter direction with respect to the rotation direction A of the intermediate transfer belt 421. The material of the scraper is, for example, a metal such as stainless steel, but any other material may be used.

The paper transport unit 50 includes a paper feed unit 51, a paper discharge unit 52, a transport path unit 53, and the like. The three paper feed trays 51a to 51c constituting the paper feed unit 51 accommodate the paper P identified based on the basis weight, size, and the like for each preset type. The transport path portion 53 has a plurality of transport roller pairs such as a resist roller pair 53a.

The paper P housed in the paper feed trays 51a to 51c is sent out one by one from the uppermost portion, and is conveyed to the image forming unit 40 by the transfer path unit 53. At this time, the resist roller portion in which the resist roller pair 53a is arranged corrects the inclination of the fed paper P and adjusts the transfer timing. Then, the paper P image-formed through the image forming unit 40 and the fixing unit 60 is discharged to the outside of the machine by the paper ejection unit 52 provided with the paper ejection roller 52a.

The fixing unit 60 secondarily transfers the toner image and heats and pressurizes the conveyed paper P with the fixing nip to fix the toner image on the paper P. The fixing portion 60 includes a fixing belt 61, a heating roller 62, a fixing roller 63, a pressure roller 64, and the like. The fixing belt 61 is stretched by a heating roller 62 and a fixing roller 63. The pressure roller 64 forms a fixing nip that sandwiches and conveys the paper P with the fixing belt 61.

By the way, in the image forming apparatus 1 having the lubricant supply unit 450 described above, when image formation is performed on uneven paper having unevenness such as embossed paper, if the amount of lubricant on the intermediate transfer belt 421 is large, toner on the uneven paper is obtained. It was found that the transferability of the image deteriorated.

Therefore, in the present embodiment, the image forming apparatus 1 includes an intermediate transfer belt 421 capable of supporting a toner image and a lubricant supply unit 450 for supplying a lubricant on the intermediate transfer belt 421. Then, in the image forming apparatus 1, the intermediate transfer belt 421 is compared with the case where the toner image is formed on a recording medium other than the uneven paper before the toner image is formed on the uneven paper via the intermediate transfer belt 421. A control unit 70 for reducing the amount of the upper lubricant is provided.

When the image forming apparatus 1 forms an image on uneven paper, the control of the control unit 70 for reducing the lubricant from the intermediate transfer belt 421 will be described with reference to FIG. 7. FIG. 7 is a flowchart illustrating an example of a lubricant reducing method carried out by the image forming apparatus 1.

(Step S11)
When an operation command such as an image forming operation or a correction operation is instructed in the image forming apparatus 1, the control unit 70 confirms whether or not to use the uneven paper. When the uneven paper is used (YES), the process proceeds to step S12, and when the uneven paper is not used (NO), the process proceeds to step S16. The correction operation is an operation of correcting the performance related to image formation in the image forming apparatus 1.

The operation command of the image forming operation is instructed, for example, when the user presses the start button of the operation display unit 20. The operation command of the correction operation is instructed, for example, when the user starts the operation on the operation display unit 20. Further, when the control unit 70 determines that the execution condition of the correction operation is satisfied, the operation command of the correction operation is instructed before the start of the image formation operation or at the time of non-image formation including the space between papers during the image formation operation. Will be done.

Further, the control unit 70 determines the use of the uneven paper by confirming the information regarding the paper to be image-formed. For example, the user can input or select information (paper information) of the type of paper set in the paper feed trays 51a to 51c on the paper setting screen displayed on the display unit 21 of the operation display unit 20 (selection unit). be. The control unit 70 confirms the paper feed tray currently in use, and if the paper information of the paper feed tray is uneven paper (for example, embossed paper), determines that the uneven paper is used.

Further, when the paper information of at least one of the paper feed trays 51a to 51c is uneven paper, the control unit 70 determines that the image forming operation using the uneven paper may be performed, and the unevenness is formed. You may decide to use paper. That is, it may be determined that the uneven paper is used only because the image forming operation using the uneven paper may be performed. On the contrary, when the paper information is not uneven paper in any of the paper feed trays 51a to 51c, the control unit 70 determines that the image forming operation using the paper other than the uneven paper is performed, and uses the uneven paper. You may decide not to use it.

Instead of inputting or selecting the paper information described above, the smoothness of the paper may be input. Further, a detector for detecting the physical characteristics of the paper may be provided in, for example, the transport path unit 53, and the control unit 70 may determine the use of the uneven paper based on the detection result of the detector.

(Step S12)
The control unit 70 confirms whether the operation command is a correction operation. If it is a correction operation (YES), the process proceeds to step S14, and if it is not a correction operation (NO), that is, if it is an image formation operation, the process proceeds to step S13.

(Step S13)
The lubricant on the intermediate transfer belt 421 that is the image carrier is removed. Specifically, with reference to FIG. 4, the intermediate transfer belt 421 is idlely rotated, and the intermediate transfer belt 421 passing through the cleaning blade of the main cleaner 426 and the scraper of the sub cleaner 427 is polished to polish the intermediate transfer belt 421. Remove the lubricant adhering to the top.

When the intermediate transfer belt 421 is idlely rotated, the intermediate transfer belt 421 is brought into contact with the cleaning blade of the main cleaner 426 and the scraper of the sub cleaner 427, but is brought into contact with the photoconductor drum 413 and the secondary transfer roller 424. Not separated. That is, the intermediate transfer belt 421 is idling with respect to the photoconductor drum 413 and the secondary transfer roller 424 other than the main cleaner 426 and the sub cleaner 427. As described above, in the idle rotation in the lubricant removing operation, the intermediate transfer belt 421 is not in contact with the photoconductor drum 413. On the other hand, in the idle rotation in the correction operation, the intermediate transfer belt 421 is in contact with the photoconductor drum 413. Therefore, from now on, the idle rotation in the lubricant removing operation is referred to as the removal space-time rotation.

In this way, when the image forming operation on the uneven paper is performed, the lubricant removing operation for removing the lubricant adhering to the intermediate transfer belt 421 is performed before starting the image forming operation. Here, the lubricant removing operation is performed before the start of the image forming operation, but in the case of the correction operation performed during the image forming operation, the image forming operation is temporarily interrupted due to a mechanical operation or the like. May perform a lubricant removing operation before resuming the operation. Further, during the image forming operation, the image forming operation may be interrupted periodically and the lubricant removing operation may be performed before restarting the image forming operation.

The lubricant removing operation is performed before starting the image forming operation on the uneven paper, but even if it is performed before starting the image forming operation on the paper other than the uneven paper, for example, plain paper, the plain paper It does not mean that there is a problem with the image formation operation. That is, as described in step S11, there is a possibility that the image forming operation using the uneven paper is performed, and it may be determined that the uneven paper is used and the lubricant removing operation may be performed. However, considering that the time required for the lubricant removing operation is required, it is desirable not to perform the lubricant removing operation in the case of paper other than uneven paper.

(Step S14)
In step S12, when the operation command is a correction operation, the correction operation of the image forming apparatus 1 is performed, but the lubricant removal operation is performed after the correction operation, or the correction operation is performed so as to reduce the supply amount of the lubricant. do.

When the lubricant removing operation is performed after the correction operation, the lubricant is removed by the main cleaner 426 and the sub cleaner 427 as described in step S13.

When the correction operation is performed by reducing the supply amount of the lubricant, the lubricant is less likely to adhere to the intermediate transfer belt 421 during the correction operation than in the case of paper other than uneven paper (for example, plain paper). ..

Explaining with reference to FIG. 6, by stopping the supply of the lubricant to the photoconductor drum 413 by the lubricant supply unit 450, the lubricant is not supplied from the photoconductor drum 413 to the intermediate transfer belt 421, and the lubricant is intermediate. Make it difficult to adhere to the transfer belt 421. For example, as described in Modification 4 described later, the brush 451 may be separated from the photoconductor drum 413 in the lubricant supply unit 450. Further, as described in the modified example 5 described later, the rotation of the brush 451 may be stopped.

(Step S15)
The control unit 70 confirms whether or not the image forming operation continues after the correction operation. If the image forming operation continues (YES), the process proceeds to step S16, and if it does not continue (NO), a series of procedures is terminated.

(Step S16)
The control unit 70 performs an image forming operation in the image forming apparatus 1. In the case of plain paper, the image forming operation is performed without reducing the lubricant on the intermediate transfer belt 421 by the above procedure. On the other hand, in the case of uneven paper, the lubricant on the intermediate transfer belt 421 is reduced by the above-mentioned procedure, and the image forming operation is performed.

As described above, the image forming apparatus 1 of the present embodiment includes an intermediate transfer belt 421 capable of supporting a toner image and a lubricant supply unit 450 for supplying a lubricant on the intermediate transfer belt 421. Then, in the image forming apparatus 1, the intermediate transfer belt 421 is compared with the case where the toner image is formed on a recording medium other than the uneven paper before the toner image is formed on the uneven paper via the intermediate transfer belt 421. A control unit 70 for reducing the amount of the upper lubricant is provided.

According to the image forming apparatus 1 of the present embodiment configured as described above, when the image is formed on the uneven paper, the amount of the lubricant on the intermediate transfer belt 421 is reduced, so that the toner is transferred even on the uneven paper. The sex can be improved.

[Modification 1]
In this modification, the configuration of the image forming apparatus 1 is as described in the above embodiment. Further, in the present modification, the method for reducing the lubricant carried out by the image forming apparatus 1 is basically the same as that of the above embodiment (see FIG. 7). On the other hand, in this modification, in the lubricant removing operation, toner is sent to the main cleaner 426 and the sub cleaner 427, which is different from the above embodiment.

In the lubricant removing operation, as described above, the main cleaner 426 and the sub cleaner 427 are brought into contact with the intermediate transfer belt 421, and the intermediate transfer belt 421 is rotated in space-time for removal. At this time, if the toner is present on the intermediate transfer belt 421, the toner can be sent to the main cleaner 426 and the sub cleaner 427. When the toner is sent to the main cleaner 426 and the sub cleaner 427, the toner acts as an abrasive, and the effect of removing the lubricant on the intermediate transfer belt 421 can be improved.

For example, the toner may be supplied onto the intermediate transfer belt 421 by transferring the toner image from the photoconductor drum 413 to the intermediate transfer belt 421 before the intermediate transfer belt 421 is spatiotemporally rotated for removal. Further, a device for supplying toner may be separately provided on the intermediate transfer belt 421.

When the three types of correction operations A to C shown in FIG. 2 are performed in the image forming apparatus 1, the transferability ranks when the respective correction operations A to C are performed are as shown in FIG. Become.

The transcriptional rank is more specifically defined as follows. This is the same rule in FIGS. 1 and 2 and FIGS. 8, 9 and 16 to 18 described later.
Rank 5; No problem Rank 4; Slight transfer failure is seen, but sufficiently acceptable level Rank 3; Some transfer failure areas are acceptable level Rank 2; Transfer failure area is extensive and NG level Rank 1 Full transfer failure

As described with reference to FIG. 2, the idle rotation times a to c of the correction operations A to C are a> b> c, and the transfer is performed in the correction operation A having the longest idle rotation time a without image formation. The sex rank has deteriorated to the NG level.

After performing the above correction operation A, when the lubricant removing operation is performed, the conditions of the toner feed amount to be fed to the main cleaner 426 and the sub cleaner 427 and the idle rotation time for idling when the intermediate transfer belt 421 is removed are changed. Transcription rank was evaluated. Here, under each condition, toner was first sent to the main cleaner 426 and the sub-cleaner 427, and then the intermediate transfer belt 421 was removed and spatiotemporally rotated. FIG. 8 is a graph for evaluating the transferability rank of the uneven paper with respect to the toner feed amount and the idle rotation time of the space-time rotation during removal. In this evaluation, the trade name Rezac 66 (registered trademark), white, and basis weight 302 g / m ² were used as the embossed paper which is the uneven paper, and two layers (blue) were formed as the image evaluation. A solid image was used on the entire surface.

As shown in FIG. 8, the transferability rank immediately after performing the correction operation A was “1.5” (0 g, 0 second point in FIG. 8). After performing such a correction operation A, the transferability rank is improved as shown in FIG. 8 by performing a lubricant removing operation in which the toner feed amount and the idle rotation time of the space-time rotation during removal are changed. For example, even if the toner feed amount is 0 g, if the idle rotation time of the space-time rotation during removal is 60 seconds, the transferability rank is improved to "3.0" (0 g, 60 seconds point in FIG. 8). Further, if the toner feeding amount is 9 g and the idle rotation time of the space-time rotation during removal is 80 seconds, the transferability rank is improved to "4.0" (9 g in FIG. 8, points of 80 seconds).

Here, the transferability rank 3 is set as an allowable level. The permissible level can be appropriately changed according to the configuration of the image forming apparatus 1 and the required image quality. When the line T1 of the transferability rank 3 is shown by a dotted line in FIG. 8, the condition of the region above the line T1 is an allowable level. In FIG. 8, in order to achieve the transferability rank 3.0, for example, when the condition that the toner consumption is the smallest and the idle rotation time of the space-time rotation during removal is the shortest is set as the lubricant removing operation, the toner is fed. The amount may be 2 g, and the idle rotation time of the space-time rotation during removal may be 20 seconds. The conditions for the lubricant removal operation are set according to whether the suppression of toner consumption is prioritized, the reduction of the idle rotation time of the space-time rotation during removal is prioritized, the improvement of the transferability rank is prioritized, and the like. It can be changed as appropriate.

As described above, the conditions for the lubricant removing operation are set. Then, after performing the correction operations A to C shown in FIG. 2, a lubricant removing operation is performed under the conditions that the toner feed amount is 2 g and the idle rotation time of the space-time rotation during removal is 20 seconds, and these are corrected. The transferability rank is evaluated as A1 to C1. FIG. 9 is a graph for evaluating the transferability rank on uneven paper when the lubricant removing operation is performed after the correction operations A to C.

As shown in FIG. 9, in the correction operation A1 in which the lubricant removing operation is performed after the correction operation A is performed, the transferability rank is improved to "3.0". Further, in the correction operation B1 in which the lubricant removal operation is performed after the correction operation B is performed, the transferability rank is improved to "3.5", and the correction operation in which the lubricant removal operation is performed after the correction operation C is performed. C1 has an improved transferability rank of "4.0".

As described above, the image forming apparatus 1 of the present modification includes a toner supply unit that supplies toner to the main cleaner 426 and the sub cleaner 427 and causes the main cleaner 426 and the sub cleaner 427 to clean the lubricant together with the toner.

According to the image forming apparatus 1 of the present embodiment configured as described above, after performing the correction operation, toner is sent to the main cleaner 426 and the sub cleaner 427 to remove the lubricant that performs space-time rotation for removing the intermediate transfer belt 421. The operation will be carried out. Thereby, the toner that acts as an abrasive can be used to improve the effect of removing the lubricant on the intermediate transfer belt 421. As a result, the transferability to uneven paper can be improved.

Also here, the correction operation is performed by the user's start operation of the correction operation, as in the above embodiment. Further, when the execution condition of the correction operation is satisfied, the correction operation is performed before the start of the image formation operation or at the time of non-image formation including the space between papers during the image formation operation.

Here, although the lubricant removing operation is performed after the correction operation is performed, the lubricant removing operation may be performed during the correction operation or may be performed a plurality of times. In any case, it is preferable to carry out the lubricant removing operation after the operation in which the lubricant is most likely to be transferred onto the intermediate transfer belt 421.

Further, here, the lubricant removing operation was performed for all of the correction operations A to C, but the transferability rank was less than the permissible level in order to suppress the toner consumption and shorten the idle rotation time of the space-time rotation during removal. The lubricant removing operation may be performed for the correction operation A which is "1.5".

Further, as shown in FIG. 4, the main cleaner 426 may be configured to have a space S for storing the toner removed by the cleaning blade. In this case, the toner stored in the space S comes into contact with the intermediate transfer belt 421 on the surface, so that the lubricant can be polished more effectively.

Further, in the cleaning blade of the main cleaner 426 and the scraper of the sub-cleaner 427 that remove the lubricant, the contact conditions thereof may be different between the lubricant removing operation and the image forming operation. For example, during the lubricant removing operation, the contact conditions such as the contact force of the cleaning blade and the scraper, the contact angle, and the moving speed of the intermediate transfer belt 421 may be changed to conditions that make it easier for the lubricant to be removed. Further, apart from the cleaning blade of the main cleaner 426 and the scraper of the sub cleaner 427, a contact member may be provided that abuts on the intermediate transfer belt 421 to remove the lubricant.

[Modification 2]
In this modification, the configuration of the image forming apparatus 1 is as described in the above embodiment. Further, in the present modification, the method for reducing the lubricant carried out by the image forming apparatus 1 is basically the same as that of the above embodiment (see FIG. 7). On the other hand, in this modification, as can be seen from the comparison between FIGS. 7 and 10, the point that step S21 is added is different from the above-described embodiment in the lubricant removing operation. Here, FIG. 10 is a flowchart illustrating another example of the lubricant reducing method carried out by the image forming apparatus 1.

In the flowchart of FIG. 10, the same as the flowchart of FIG. 7 described in the above embodiment except that step S21 is added between steps S12 and S13. Therefore, here, the steps that overlap with the flowchart of FIG. 7 will be briefly described.

(Step S11)
Step S11 is as described with reference to FIG.

(Step S12)
The control unit 70 confirms whether the operation command is a correction operation. If it is a correction operation (YES), the process proceeds to step S14, and if it is not a correction operation (NO), that is, if it is an image formation operation, the process proceeds to step S21.

(Step S21)
The control unit 70 confirms whether or not the correction operation having a long idle rotation time has been performed most recently. If the most recent correction operation with a long idle rotation time is performed (YES), the process proceeds to step S13, and if the most recent correction operation with a long idle rotation time is not performed (NO), the process proceeds to step S16.

As described with reference to FIG. 2, when the correction operations B and C having a short idle rotation time are performed, the time for forming the toner image on the intermediate transfer belt is long, so that the amount of lubricant on the intermediate transfer belt 421 is reduced. .. On the other hand, when the correction operation A having a long idle rotation time is performed, a large amount of lubricant remains on the intermediate transfer belt 421. Therefore, in step S21, when the correction operation A having a long idle rotation time is performed most recently, a large amount of lubricant remains on the intermediate transfer belt 421. In that case, the process proceeds to step 13.

As described above, when the correction operation A having a long idle rotation time is performed immediately before the image forming operation and a large amount of lubricant remains on the intermediate transfer belt 421, the process proceeds to step S13 to perform the lubricant removing operation. There is. When the correction operation A having a long idle rotation time is performed, a flag is set, and in step S21, it is determined whether to proceed to step S13 or step S16 depending on whether or not the flag is set. You may do it. Further, if a large amount of lubricant remains on the intermediate transfer belt 421 for a reason other than the correction operation A, a flag may be set.

(Steps S13 to S16)
Steps S13 to S16 are as described with reference to FIG.

As described above, the image forming apparatus 1 of this modification performs the lubricant removing operation when a large amount of lubricant remains on the intermediate transfer belt 421.

According to the image forming apparatus 1 of the present modification configured as described above, when a large amount of lubricant remains on the intermediate transfer belt 421, the lubricant removing operation can be performed to reduce the lubricant on the intermediate transfer belt 421. .. As a result, the transferability to uneven paper can be improved.

[Modification 3]
In this modification, the configuration of the image forming apparatus 1 is as described in the above embodiment. Further, in the present modification, the method for reducing the lubricant carried out by the image forming apparatus 1 is basically the same as that of the above embodiment (see FIG. 7). On the other hand, in this modification, in the correction operation, in addition to the correction toner image (first toner image) required for the correction operation, the lubricant image for suppressing the lubricant (second toner image) is displayed on the intermediate transfer belt 421. It is different from the above-described embodiment in that it is formed in.

In this modification, the image pattern of the toner image used in the correction operation is changed in order to prevent the lubricant from adhering to the intermediate transfer belt 421 in the correction operation.

First, the correction toner image required for the correction operation will be described with reference to FIG. FIG. 11 is a diagram showing an image pattern of the toner image in the correction operation of the toner density adjustment.

In the correction operation of the image forming apparatus 1, ATVC (Active Transfer Voltage Control) control, toner density adjustment, potential correction on the photoconductor drum 413, color registration correction, and the like are usually performed.

Toner density adjustment and color registration correction are performed by detecting a toner image formed on the intermediate transfer belt 421 with a density sensor 461 (see FIG. 4) and based on the detection result. The density sensor 461 has, for example, an irradiation unit that irradiates light toward the intermediate transfer belt 421 and a light receiving unit that receives the reflected light from the intermediate transfer belt 421, and detects the reflected light by the light receiving unit. The result is used for the above adjustments and corrections. As shown in FIG. 4, the density sensor 461 is arranged on the downstream side of the photoconductor drum 413 in the rotation direction A. Further, as shown in FIG. 11, a plurality of intermediate transfer belts 421 (two as an example in FIG. 11) are arranged in the width direction (main operation direction) of the intermediate transfer belt 421.

Therefore, toner images Ty01 to Ty03, Tc01 to Tc03, Tm01 to Tm03, and Tb01 to Tb03 necessary for toner density adjustment and color registration correction are formed at positions on the intermediate transfer belt 421 passing through the density sensor 461. There is. In FIG. 11, Wmax is the maximum image width of the intermediate transfer belt 421. Further, in FIGS. 11 and 12 to 15 described later, reference numeral Ty is a yellow toner image, reference numeral Tc is a cyan toner image, reference numeral Tm is a magenta toner image, and reference numeral Tb is a black toner image. show.

In the toner images Ty01 to Ty03, Tc01 to Tc03, Tm01 to Tm03, and Tb01 to Tb03 shown in FIG. 11, the area thereof is minimized in order to prevent unnecessary toner consumption. Therefore, there are many regions where the toner does not exist, and the lubricant easily adheres to the intermediate transfer belt 421.

Therefore, in this modification, in addition to the toner image required for the correction operation, a toner image for suppressing the lubricant is formed on the intermediate transfer belt 421 so as to suppress the lubricant from being transferred to the intermediate transfer belt 421. There is.

For example, FIG. 12 is a diagram showing an example (image pattern 1) of an image pattern of a toner image in a correction operation for suppressing lubricant adhesion.

In FIG. 12, in addition to the toner images Ty01 to Ty03, Tc01 to Tc03, Tm01 to Tm03, and Tb01 to Tb03 shown in FIG. 11, the toner image T11 for suppressing the lubricant is formed on the intermediate transfer belt 421.

As shown in FIG. 12, on the intermediate transfer belt 421, the toner images Ty01 to Ty03, Tc01 to Tc03, Tm01 to Tm03, and Tb01 to Tb03 are filled, that is, the area where the toner does not exist is filled. The toner image T11 is formed. In this way, in addition to the toner images Ty01 to Ty03, Tc01 to Tc03, Tm01 to Tm03, and Tb01 to Tb03, the toner image T11 is also formed so as to cover the lubricant adhering to the photoconductor drum 413. This can prevent the transfer of the lubricant from the photoconductor drum 413 to the intermediate transfer belt 421, and prevent the lubricant from adhering to the intermediate transfer belt 421. Further, in the region where the toner image is formed, the toner image is transferred from the photoconductor drum 413 to the intermediate transfer belt 421 instead of the lubricant. Therefore, the toner that acts as an abrasive for the lubricant can be supplied to the intermediate transfer belt 421, and the effect of removing the lubricant on the intermediate transfer belt 421 can be improved.

The toner image T11 may be a halftone image. Further, if the region where the toner does not exist can be filled without changing the toner images Ty01 to Ty03, Tc01 to Tc03, Tm01 to Tm03, and Tb01 to Tb03, the toner image T11 is not the pattern shown in FIG. The pattern may be.

Further, FIG. 13 is a diagram showing another example (image pattern 2) of the image pattern of the toner image in the correction operation of suppressing the lubricant adhesion.

In FIG. 13, the toner images Ty11 to Ty13, Tc11 to Tc13, Tm11 to Tm13, and Tb11 to Tb13 are formed on the intermediate transfer belt 421. That is, the toner images Ty01 to Ty03, Tc01 to Tc03, Tm01 to Tm03, and Tb01 to Tb03 shown in FIG. 11 are not changed and are expanded in the main operation direction of the intermediate transfer belt 421.

As shown in FIG. 13, toner images Ty11 to Ty13, Tc11 to Tc13, Tm11 to Tm13, and Tb11 to Tb13 are formed on the intermediate transfer belt 421 so that the area where the toner does not exist is reduced. This can prevent the lubricant from adhering to the intermediate transfer belt 421.

As shown in FIG. 13, it is not necessary to fill the intermediate transfer belt 421 with the toner image, but it is preferable that at least one region is filled with the toner image in the entire main scanning direction. This is because if the entire main scanning direction is filled with the toner image in one area, even if there is a region where there is no toner image in the sub scanning direction, there is a region in the main operating direction in which the toner is sent to that region. Is. The lubricant adhering to the intermediate transfer belt 421 from the region without the toner image can be removed by polishing with the toner sent from the region with the toner image.

On the other hand, even if the entire sub-scanning direction is filled with the toner image in one area, if there is a region where there is no toner image in the main scanning direction, there is no other region in the main scanning direction for feeding the toner to that region. In some cases. In that case, the lubricant adhering to the intermediate transfer belt 421 from the region where there is no toner image is cleaned in a state where the toner as an abrasive is not sent, and the lubricant may remain. As described above, from the viewpoint of removing the lubricant by the toner, it is permissible for the toner image to be lost in the sub-scanning direction, but it is better that the toner image is not lost in the main scanning direction.

Further, FIG. 14 is a diagram showing another example (image pattern 3) of the image pattern of the toner image in the correction operation of suppressing the lubricant adhesion.

In FIG. 14, in addition to the toner images Ty02 to Ty03, Tc01 to Tc03, Tm02 to Tm03, and Tb01 to Tb03 shown in FIG. 11, the toner images Ty11, Tm11, T21, and T22 are formed on the intermediate transfer belt 421. There is. The toner images Ty11 and Tm11 are expanded in the main operation direction of the intermediate transfer belt 421 without changing the portions of the toner images Ty01 and Tm01 shown in FIG. Further, the toner images T21 and T22 are halftones, and the toner images Tc01 and Tb01 shown in FIG. 11 are extended in the main operation direction of the intermediate transfer belt 421.

As shown in FIG. 14, it is not necessary to fill the intermediate transfer belt 421 with the toner image, but it is preferable that at least one region is filled with the toner image in the entire main scanning direction. The reason for this is as described in FIG.

Further, in FIG. 14, as shown by the toner images Ty11 and Tm11, the solid image may be expanded in the main operation direction of the intermediate transfer belt 421. Further, as shown by the toner images T21 and T22, the toner images Tc01 and Tb01 may be extended in halftone toward the main operation direction of the intermediate transfer belt 421. By setting the toner images T21 and T22 to halftone, the amount of toner consumed can be suppressed.

Further, FIG. 15 is a diagram showing another example (image pattern 4) of the image pattern of the toner image in the correction operation of suppressing the lubricant adhesion.

Depending on the correction operation, there is an operation in which the toner image should not be present, such as the potential correction on the photoconductor drum 413. The potential correction on the photoconductor drum 413 is performed based on the detection result of a potential sensor (not shown) that is provided facing the surface of the photoconductor drum 413 and detects the surface potential of the photoconductor drum 413. In the case of such correction, as shown in FIG. 15, the toner images Ty21, Tm21, except for the regions f1 to f4 on the intermediate transfer belt 421 corresponding to the region on the photoconductor drum 413 detected by the potential sensor, Tc21 and Tb21 are formed on the intermediate transfer belt 421. That is, the toner images Ty21, Tm21, Tc21, and Tb21 are formed on the intermediate transfer belt 421 in the region not detected by the potential sensor. In FIG. 15, the toner images Ty21, Tm21, Tc21, and Tb21 are arranged between the regions f1 and f2 and the regions f3 and f4 in the sub-scanning direction, and are formed in a band shape extending in the main operation direction. .. Further, the halftone toner images T31 to T33 may be formed so as to sandwich the regions f3 and f4.

The toner images Ty21, Tm21, Tc21, and Tb21 are appropriately changed according to the content of the correction operation, but also in FIG. 15, all the main scanning directions are filled with the toner image, and the reason for this is FIG. As explained in.

Although FIGS. 12 to 15 show an example of an image pattern for forming a toner image for removing lubricant, the color and the amount of toner adhered to any of the toner images can be appropriately changed.

However, in the correction operation including the image density correction, if the toner consumption is too large, the state of the material may change during the correction operation, and the image density correction result may become abnormal. Therefore, the toner image is formed only in a part of the region. Further, the toner consumption is suppressed by forming the toner image with a halftone or the like in which the amount of toner adhered is suppressed. As described above, when the toner image that suppresses the toner consumption is used, it may be used in combination with the lubricant removing operation shown in the modification 1 as described in the modification 6 described later. In this case, transferability equivalent to that of the first modification can be obtained even if the toner feeding amount and the idle rotation time of the space-time rotation during removal are reduced in the lubricant removing operation shown in the first modification.

Here, the correction operation A is set as the correction operation to be performed by the image forming apparatus 1 shown in FIG. 4, and the above image patterns 1 to 3 are set as the image pattern of the toner image used in the correction operation A. , A new correction operation A2 to A4 was carried out. The correction operation A2 is a correction operation A using the image pattern 1, the correction operation A3 is a correction operation A using the image pattern 2, and the correction operation A4 is a correction operation A using the image pattern 3. ..

FIG. 16 is a graph for evaluating the transferability rank on uneven paper when the image patterns 1 to 3 are used in the correction operation A. As shown in FIG. 16, the transferability ranks of the correction operations A2 to A4 are all improved from the transferability ranks of the correction operation A. Among the correction operations A2 to A4, the correction operation A3 having the highest transferability rank is the image pattern 2 having the largest amount of toner adhered. From this result, assuming that the transferability rank 3 is an allowable level, the image pattern 2 or 3 is preferable as the image pattern used in the correction operation A.

As described above, in this modification, in addition to the correction toner image required for the correction operation, a toner image for suppressing the lubricant is formed on the intermediate transfer belt 421 (toner image forming portion). As a result, when the toner image is first transferred from the photoconductor drum 413 to the intermediate transfer belt 421, the chance (area) that the intermediate transfer belt 421 comes into contact with the lubricant is reduced due to the toner image for suppressing the lubricant. Further, the lubricant image for suppressing the lubricant transferred to the intermediate transfer belt 421 is added to the toner image for correction, and the toner is supplied to the intermediate transfer belt 421. As described in step S13, the toner acts as an abrasive, so that the effect of removing the lubricant is improved.

In the correction operation, ATVC control, toner density adjustment, potential correction on the photoconductor drum 413, color registration correction, and the like are usually performed. In this modification, the operation contents such as the toner image for correction, the toner image for suppressing the lubricant, and the time required for the correction operation can be appropriately changed in consideration of these controls, adjustments, and corrections.

As described above, in the correction operation, the image forming apparatus 1 of the present modification operates a toner image for forming a toner image for removing lubricant other than the toner image for correction required for the correction operation on the intermediate transfer belt 421. It has a forming part.

According to the image forming apparatus 1 of the present modification configured as described above, in the correction operation, a toner image for removing the lubricant is formed on the intermediate transfer belt 421. Therefore, the toner acting as an abrasive is used to form the intermediate transfer belt 421. The upper lubricant can be removed. This makes it possible to reduce the lubricant on the intermediate transfer belt 421. As a result, the transferability to uneven paper can be improved.

[Modification 4]
In this modification, the configuration of the image forming apparatus 1 is as described in the above embodiment. Further, in the present modification, the method for reducing the lubricant carried out by the image forming apparatus 1 is basically the same as that of the above embodiment (see FIG. 7). On the other hand, in this modification, the configuration and operation of the lubricant supply unit 450 are different from those of the above embodiment with respect to the correction operation (see FIG. 6).

In this modification, the lubricant supply unit 450 is separated from the photoconductor drum 413 in order to suppress the adhesion of the lubricant in the correction operation.

Explaining with reference to FIG. 6, the lubricant supply unit 450 further has a cam 455. The support sheet metal 454 supports the brush 451 and the lubricant 452, and extends outward from the side surface of the lubricant 452. Further, the cam 455 is rotatably provided, and when the cam 455 is rotated at a predetermined angle, it comes into contact with the support sheet metal 454, and the cam 455 moves the support sheet metal 454 downward. Since the support sheet metal 454 supports the brush 451 and the lubricant 452, when the support sheet metal 454 moves downward, the brush 451 is separated from the photoconductor drum 413.

Then, in the correction operation of step S14 in FIG. 7 described above, the control unit 70 rotates the cam 455 to separate the brush 451 from the photoconductor drum 413 so that the lubricant adheres to the photoconductor drum 413. It can be suppressed.

As described above, in the image forming apparatus 1 of the present modification, the control unit 70 separates the lubricant supply unit 450 from the photoconductor drum 413 in the correction operation.

According to the image forming apparatus 1 of the present modification configured as described above, in the correction operation, the lubricant supply unit 450 can be separated from the photoconductor drum 413 so that the lubricant does not adhere to the photoconductor drum 413. .. This makes it possible to reduce the lubricant on the intermediate transfer belt 421. As a result, the transferability to uneven paper can be improved.

Here, the cam 455 is used as a separating mechanism for separating the lubricant supply unit 450 from the photoconductor drum 413, but if the configuration functions as a separating mechanism, a device other than the cam, for example, an actuator or the like is used. You may.

[Modification 5]
In this modification, the configuration of the image forming apparatus 1 is as described in the above embodiment. Further, in the present modification, the method for reducing the lubricant carried out by the image forming apparatus 1 is basically the same as that of the above embodiment (see FIG. 7). On the other hand, in this modification, the operation of the lubricant supply unit 450 is different from that of the above embodiment with respect to the correction operation (see FIG. 6).

In this modification, the control unit 70 stops the supply of the lubricant by the lubricant supply unit 450 in order to suppress the adhesion of the lubricant in the correction operation.

Explaining with reference to FIG. 6, in the lubricant supply unit 450, the brush 451 that supplies the lubricant to the photoconductor drum 413 is connected to the drive motor via a gear and is rotationally driven in the rotation direction R2. The gear and drive motor are not shown. In this modification, the control unit 70 stops the drive motor when performing the correction operation, thereby stopping the supply of the lubricant by the lubricant supply unit 450. That is, the lubricant supply unit 450 is prevented from operating.

As described above, in the image forming apparatus 1 of the present modification, the control unit 70 stops the supply of the lubricant by the lubricant supply unit 450 in the correction operation.

According to the image forming apparatus 1 of the present modification configured as described above, in the correction operation, the supply of the lubricant by the lubricant supply unit 450 can be stopped to prevent the lubricant from adhering to the photoconductor drum 413. This makes it possible to reduce the lubricant on the intermediate transfer belt 421. As a result, the transferability to uneven paper can be improved.

[Modification 6]
In the modified examples 1 and 2, the transferability of the uneven paper is improved by removing the lubricant from the intermediate transfer belt 421 by the lubricant removing operation. Further, in the modified examples 3 to 5, the transferability of the uneven paper is improved by performing a correction operation in which the lubricant is less likely to adhere to the intermediate transfer belt 421. By combining the lubricant removing operation shown in the modified examples 1 and 2 and the correction operation shown in the modified examples 3 to 5 in which the lubricant is less likely to adhere, it is possible to further improve the transferability of the uneven paper.

For example, in consideration of suppressing the toner consumption, the lubricant removing operation of the modified example 1 and the correction operation A2 of the modified example 3 are combined. Here, after performing the correction operation A2 of the modification 3, in the lubricant removing operation of the modification 1, the conditions of the toner feed amount and the idle rotation time of the space-time rotation during removal were changed to evaluate the transferability rank.

FIG. 17 is a graph for evaluating the transferability rank of the uneven paper with respect to the toner feed amount and the idle rotation time of the space-time rotation during removal. Again, the transferability rank 3 is the permissible level. When the line T2 of the transferability rank 3 is shown by a dotted line in FIG. 17, the condition of the region above the line T2 is an allowable level. In FIG. 17, in order to achieve the transferability rank 3.0, for example, when the condition that the toner consumption is the smallest and the idle rotation time of the space-time rotation during removal is the shortest is set as the lubricant removing operation, the toner is fed. The amount may be 1.5 g, and the idle rotation time of the space-time rotation during removal may be 15 seconds. Under this condition, the toner consumption of the lubricant removing operation and the idle rotation time of the space-time rotation during removal can be reduced as compared with the modified example 1.

FIG. 18 is a graph for evaluating the transferability rank on uneven paper when the lubricant removing operation is performed after the correction operation. Specifically, in the correction operation A5, after the correction operation A2 was performed, the lubricant removing operation was performed with the toner feed amount being 1.5 g and the idle rotation time of the space-time rotation during removal being 15 seconds. Further, in the correction operation B2, after the correction operation B was performed, the lubricant removing operation was performed with the toner feeding amount being 1.5 g and the idle rotation time of the space-time rotation during removal being 15 seconds. Further, in the correction operation C2, after the correction operation C was performed, the lubricant removing operation was performed with the toner feeding amount being 1.5 g and the idle rotation time of the space-time rotation during removal being 15 seconds.

As can be seen by comparing FIGS. 16 and 18, the transferability to uneven paper is improved in each case.

[Other variants]
In order to improve the transferability of the uneven paper, an intermediate transfer belt (hereinafter referred to as a coated belt) coated with a coat layer containing _{glass (SiO 2) as a main component is used as the intermediate transfer belt 421.} As such a coat belt is used, the transferability of the uneven paper may deteriorate.

As shown in FIG. 19, the coating layer containing glass as a main component has a -OH group as a terminal group due to its structure. It is considered that the discharge product has a property of easily adhering to the −OH group, and therefore the lubricant deteriorates and deteriorates, resulting in a phenomenon that the transferability deteriorates. Before and after the image formation, the analysis of the surface of the coated belt in ion chromatography, as shown in FIG. 20, initially the NO ₃ was not detected is detected after continuous 50,000 sheets treatment, discharge It can be confirmed that the product adheres to the surface of the coat belt.

As described above, the image forming apparatus 1 using the coated belt as the intermediate transfer belt 421 may deteriorate the transferability of the uneven paper as it is used. If the configuration is applied, deterioration of the transferability can be prevented.

Further, it is desirable that the coat belt used as the intermediate transfer belt 421 has a ten-point average roughness Rzjis of 0.6 to 1.3 μm for the following reasons. Specifically, the ten-point average roughness Rzjis may be 0.6 μm or more in consideration of sensor noise in an optical sensor that optically detects toner on a coat belt, for example, the density sensor 461. desirable. Further, the ten-point average roughness Rzjis is preferably 1.3 μm or less in consideration of the cleanability (presence or absence of unwiped residue) of the coat belt by the main cleaner 426 and the sub cleaner 427.

Compared with the intermediate transfer belt having a smoother surface, the coated belt having such a surface roughness tends to take in the lubricant in the recess due to the surface roughness, and the transferability of the uneven paper may be deteriorated. Even in the image forming apparatus 1 using such a coat belt, if the above-described embodiment and the modifications 1 to 6 are applied, it is possible to prevent the transferability from being deteriorated.

Here, the coat belt is exemplified as the intermediate transfer belt 421, but instead of this, a PI belt or an elastic belt can obtain the same effect as the coat belt.

Further, in the above-described embodiments and modifications 1 to 6, the case where the image carrier is the intermediate transfer belt 421 is exemplified, but even when the image carrier is the photoconductor drum 413 and the direct transfer method is used. , The present invention is applicable. In this case as well, the same effect as in the case of the intermediate transfer belt 421 can be obtained.

Further, in the above-described embodiments and modifications 1 to 6, the case where the lubricant supply unit 450 is installed on the photoconductor drum 413 is exemplified, but the lubricant supply unit 450 directly supplies the lubricant to the intermediate transfer belt 421. The present invention is applicable even in the configuration. In this case as well, the same effect as when installed on the photoconductor drum 413 can be obtained.

It should be noted that the above embodiments are merely examples of embodiment of the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from its gist or its main features.

1 Image forming device 10 Image reading unit 20 Operation display unit 30 Image processing unit 40 Image forming unit 50 Paper transport unit 60 Fixing unit 70 Control unit 415 Cleaning unit 421 Intermediate transfer belt 426 Main cleaner 427 Sub cleaner 450 Lubricating agent supply unit

Claims (11)

An image carrier capable of supporting a toner image and an image carrier
A lubricant supply unit that supplies the lubricant onto the image carrier,
The lubricant on the image carrier is compared with the case where the toner image is formed on a recording medium other than the uneven paper before the toner image is formed on the uneven paper via the image carrier. A control unit that reduces the amount,
An image forming apparatus. A cleaning unit for cleaning the lubricant on the image carrier is provided.
The image forming apparatus according to claim 1. The control unit causes the cleaning unit to clean the lubricant on the image carrier after performing a correction operation for correcting the performance related to image formation.
The image forming apparatus according to claim 2. The control unit separates the image carrier from other than the cleaning unit.
The image forming apparatus according to any one of claims 2 or 3. A toner supply unit that supplies toner to the cleaning unit and causes the cleaning unit to clean the lubricant together with the toner is provided.
The image forming apparatus according to any one of claims 2 to 4. The cleaning unit has a space for storing the toner.
The image forming apparatus according to claim 5. The control unit is described in the correction operation performed when an image is formed on the uneven paper, as compared with a correction operation for correcting the performance related to image formation performed when the image is formed on a recording medium other than the uneven paper. To reduce the supply of the lubricant to the image carrier,
The image forming apparatus according to any one of claims 1 to 6. In the correction operation, a toner image forming portion for forming a second toner image on the image carrier is provided so as to fill the space between the first toner images required for the correction operation.
The image forming apparatus according to claim 7. The control unit separates the lubricant supply unit from the image carrier in the correction operation.
The image forming apparatus according to claim 7. The control unit stops the supply of the lubricant by the lubricant supply unit in the correction operation.
The image forming apparatus according to claim 7. A selection unit for selecting the type of recording medium to be image-formed is provided.
The control unit reduces the lubricant on the image carrier when the selected recording medium contains uneven paper.
The image forming apparatus according to any one of claims 1 to 10.

Images