JP2016053646A - Transfer belt unit and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transfer belt unit and an image forming apparatus which include a cleaning mechanism for extending the service life of a cleaning blade with a simple configuration.SOLUTION: In a transfer belt unit 3 which includes a transfer belt 8 and a cleaning blade 28 and is detachably attached to a printer 1, a cleaning blade lubricity adjustment member 304 which is brought into light pressure contact with a surface 8a of the transfer belt 8 to temporarily dam up a residual material TB on the transfer belt is provided on a grip part 302a provided on the downstream side in the movement direction with respect to the position where the transfer belt 8 faces an image formation part 2 of the printer 1 and on the upstream side with respect to the pressure contact position of the cleaning blade 28, thereby the minimum necessary amount of toner as a lubricant continuously acts on the tip of the cleaning blade 28 for a long period to prevent the occurrence of buckling phenomenon and extend the service life of the cleaning blade 28.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for cleaning a transfer belt unit provided with a cleaning blade, and more particularly to a transfer belt unit and an image forming apparatus provided with a cleaning mechanism that realizes a long life of the cleaning blade with a simple configuration.

  2. Description of the Related Art Conventionally, an image is printed (hereinafter also referred to as printing) using an electrophotographic method using toner, that is, a toner image formed on a photoreceptor is directly or via a transfer belt (hereinafter also referred to as paper). 2) is widely known.

  In particular, in recent years, for example, there are many secondary transfer type image forming apparatuses that primarily transfer a toner image formed on a photosensitive drum onto an intermediate transfer belt, and further transfer the toner image on the intermediate transfer belt onto a sheet. It has become.

  In such an image forming apparatus, the surface of an image carrier that carries a toner image such as a photosensitive drum or a transfer belt that functions as an intermediate transfer medium is not transferred even after the toner image is transferred to a sheet. Since the toner remains, it is usual to provide a cleaning mechanism that removes residual toner by bringing the tip of the cleaning blade into pressure contact with the surface of the photosensitive drum or transfer belt with an appropriate slidability.

  In the above cleaning mechanism, if the frictional force between the tip of the cleaning blade and the surface of the image carrier becomes too high (in other words, the slidability decreases), a buckling phenomenon occurs at the tip, causing damage and chattering. There is a problem that abnormal noise such as that occurs or toner slips out.

  Therefore, in order to obtain an appropriate slidability, that is, lubricity, a lubricant is applied in advance to the tip of the cleaning blade. As for the slidability after the initial operation of the cleaning mechanism, when the untransferred toner generated every printing, that is, the residual toner reaches the tip of the cleaning blade, the lubricating component in the residual toner acts as a lubricant. Has been sustained.

  However, since the amount of residual toner varies depending on the printing conditions such as the image rate, printing width, and continuous printing, the above-mentioned problem still occurs because the lubricating component decreases and the frictional force becomes too high with the printing process. Were present. Therefore, it has been proposed to positively (forcefully) supply a predetermined amount of toner as a lubricant to the tip of the cleaning blade to protect the cleaning blade.

  For example, Patent Document 1 discloses that a toner is forcibly adhered on a latent image carrier between the end of a series of image forming processes and the stop of the machine, and the latent image carrier is moved by moving the surface of the latent image carrier. 2. Description of the Related Art There is known an image forming apparatus including a cleaning blade lubricity holding device which is supplied to a pressure contact portion between a surface of a carrier and a cleaning blade.

  For example, Patent Document 2 proposes an image forming apparatus including a lubricant supply amount control unit that controls an amount of toner supplied to the press contact portion to an appropriate amount.

  Each of these prior arts is directed to a photosensitive drum as an image carrier that carries a toner image, and describes supply of a lubricant to a cleaning blade that is in pressure contact with the photosensitive drum.

  On the other hand, for example, in Patent Document 3, in an image forming apparatus that transfers a toner image on a photosensitive member onto a transfer sheet conveyed by an endless transfer belt, after the transfer of the toner image to the transfer material or the jam of the transfer material When the residual toner adhering to the transfer belt due to generation or the like is removed by the cleaning blade that contacts the transfer belt, if the toner is not sent to both ends of the cleaning blade, the both ends of the cleaning blade gradually turn up. A problem is pointed out and an invention for solving this problem is described.

  That is, in Patent Document 3, a blade turning prevention toner image is formed in an area outside the image forming area of a toner image that is periodically transferred to a normal transfer material, and the blade turning prevention toner image is cleaned with a transfer belt. The cleaning blade is prevented from being turned over by supplying the toner base particles and the external additive of the toner image as lubricants.

  In addition, Patent Document 4 relates to the cleaning performance of an intermediate transfer belt as an image carrier, and a drive-type cleaning auxiliary member is provided in the vicinity of the cleaning blade of the belt cleaning device so that the tip of the cleaning blade can be used as a lubricant. A technique is disclosed in which the toner is sufficiently retained to prevent the tip portion from being turned over, deteriorated, or generate abnormal noise.

JP-A-1-108592 JP-A-5-40438 Japanese Patent Laid-Open No. 7-334012 JP 2011-090134 A

  As described above, in a cleaning system in which a cleaning blade is pressed against an image carrier, it is widely known that a predetermined amount of toner as a lubricant is positively supplied to the tip of the cleaning blade.

  However, in the case of the above Patent Documents 1 to 3, although it is pointed out that the amount of toner remaining or supplied on the image carrier and reaching the pressure contact portion between the image carrier and the cleaning blade is different, In any case, the state of the residual toner before reaching the above is not adjusted at all and is not even taken into consideration.

  That is, according to the knowledge of the present inventors, the residual toner on the image carrier reaches the pressure contact portion with the cleaning blade and acts as a lubricant, but is the amount of lubricant at that time large? Less is not a problem, it is important how long the lubricant works.

  In other words, even if the amount of toner to be actively supplied is changed according to the printing status as in the above Patent Documents 1 to 3, the amount acting as a lubricant is very small, and is consequently scraped off by the cleaning blade. It has been found that it becomes a wasteful supply of toner.

  On the other hand, in Patent Document 4, since the toner at the tip of the cleaning blade is allowed to run sideways and stay by providing a cleaning auxiliary member, the durability of the action as a lubricant is improved. I can say that. However, in this Patent Document 4, since the drive type cleaning auxiliary member is provided, the structure is complicated and the toner amount itself before reaching the cleaning blade is not adjusted, and the above problem can be solved. is not.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a transfer belt unit and an image forming apparatus including a cleaning mechanism that realizes a long life of a cleaning blade with a simple configuration.

  In order to solve the above problems, a transfer belt unit of the present invention is supported by a unit frame and a unit frame so as to be able to circulate through a drive roll and a driven roll, and image formation using toner is performed. An endless transfer belt that moves to face an image forming unit disposed in the apparatus; a cleaning blade that presses against the transfer belt and scrapes a residue including toner carried on the surface of the transfer belt; and The surface of the transfer belt that is downstream in the moving direction from the position facing the image forming portion of the transfer belt and upstream in the moving direction from the pressure contact position of the cleaning blade, and intersects the moving direction. A handle portion that is attached to and detached from the image forming apparatus, and a light pressure contact with the surface of the transfer belt disposed on the handle portion to remove the residue. Configured to include a cleaning blade lubrication adjustment member stop time to dam, the.

  In order to solve the above problems, the image forming apparatus of the present invention is configured to include the transfer belt unit in a detachable manner.

  The present invention relates to a transfer belt unit that includes an endless transfer belt and a cleaning blade and is detachable from the image forming apparatus, and is located downstream in the moving direction from the position where the transfer belt faces the image forming unit of the image forming apparatus. Because the handle provided on the upstream side of the pressure contact position of the cleaning blade is equipped with a cleaning blade lubricity adjusting member that lightly presses against the surface of the transfer belt and temporarily blocks the residue on the transfer belt. Even though it has a simple structure, the length of the cleaning blade is prevented by causing the toner as a lubricant to act on the tip of the cleaning blade continuously for a long period of time with the minimum amount necessary to prevent buckling. Life expectancy can be realized.

(a) is an external perspective view of a transfer belt unit according to an embodiment of the present invention, (b) is a top view showing a handle portion of the transfer belt unit taken out, and (c) is a view of the handle portion taken out. A bottom view, (d) is a longitudinal side view of a cleaning blade lubricity adjusting member (brush member) according to an embodiment of the present invention attached to a handle, and (e) is a cleaning blade lubricity adjusting member ( It is a figure explaining the effect | action of a brush member. It is a bottom view explaining the structure of the cleaning blade lubricity adjustment member (brush member) which concerns on another embodiment of this invention with an effect | action. (a) is a sectional view showing the internal configuration of a printer (full-color image forming apparatus) according to an embodiment of the present invention, and (b) is an enlarged view of a main part showing the vicinity of a cleaning blade provided in the printer. 1 is an external perspective view of a printer according to an embodiment of the present invention. (a) is a perspective view showing a state where a transfer belt unit and four image forming units of a printer according to an embodiment of the present invention are mounted in the apparatus main body, with a unit lock cover removed, (b) FIG. 4B is a perspective view showing a unit lock cover that prohibits removal of the transfer belt unit and the four image forming units.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described in detail with reference to the accompanying drawings. In the description of the embodiment, the same number is assigned to the same element throughout.

  FIG. 3A is a cross-sectional view showing the internal configuration of the printer according to one embodiment of the present invention, and FIG. 3B is an enlarged view of a main part showing the vicinity of a cleaning blade provided in the printer. FIG. 4 is an external perspective view of a printer according to an embodiment of the present invention.

  As shown in FIG. 3 (a), the printer 1 is an electrophotographic secondary transfer tandem type color image forming apparatus, and includes an image forming unit 2, a transfer belt unit 3, a toner supply unit 4, a paper feed unit. And a belt-type fixing unit 6 and a duplex printing conveyance unit 7.

  The image forming unit 2 is in contact with the lower running portion surface 8a of the transfer belt 8 from right to left in FIG. Four image forming units 9 (9k, 9c, 9m, 9y) are arranged in a multistage manner.

  The image forming unit 2 is held on the frame of the main body of the printer 1 so as to be movable up and down from the printing execution position shown in FIG. 3A to a maintenance position below the printing execution position. Of the four image forming units 9, three image forming units 9y, 9m, and 9c on the upstream side (the left side in the figure) are subtractive mixed primary colors yellow (Y), magenta (M), cyan ( A monocolor image is formed with the color toner of C).

  The image forming unit 9k forms a monochrome image using black (K) toner mainly used for characters and dark portions of images. Each of the image forming units 9 has the same configuration except for the color of the toner for developing the image. Accordingly, the configuration of the image forming unit 9y for yellow (Y) toner will be described below as an example.

  The image forming unit 9 includes a photosensitive drum 10 at the top. The photosensitive drum 10 has a peripheral surface made of, for example, an organic photoconductive material. A cleaner 11, a charging roller 12, an optical writing head 13, and a developing roller 15 of the developing device 14 are disposed in contact with or surrounding the periphery of the photosensitive drum 10.

  The developing device 14 includes a unit housing 16 that covers the outside, a partition wall 17 provided inside, a developing roller 15, a first stirring and conveying screw 18, and a second stirring and conveying screw 19. Although not specifically shown, the first and second agitating and conveying screws 18 and 19 include a screw shaft and a fin that is integrally formed with the screw shaft and rotates.

  The developing unit 14 includes a toner supply container 20 (20y, 20m, 20c, and 20k) of the toner supply unit 4, and yellow (Y) and magenta (M) as indicated by Y, M, C, and K in FIG. ), Cyan (C), or black (K) toner is supplied.

  The transfer belt unit 3 has an endless transfer belt 8 that extends in the shape of a flat loop in the left-right direction in the figure at approximately the center of the main unit, and the transfer belt 8 is stretched over the transfer belt 8. A driving roller 21 and a driven roller 22 are provided to circulate and move counterclockwise as indicated by an arrow a in the figure.

  Although not described in detail, a belt position control mechanism is disposed inside the flat loop shape of the transfer belt 8. A primary transfer roller 23 is integrally incorporated in the belt position control mechanism. The primary transfer roller 23 is pressed against the photosensitive drum 10 via the transfer belt 8 and directly transfers (primary transfer) the toner image to the lower running portion surface 8a of the transfer belt 8 that circulates downward.

  The transfer belt 8 conveys the toner image to the paper secondary transfer unit 24 for further transfer (secondary transfer) to the paper. The secondary transfer unit 24 includes a transfer auxiliary roller 25 disposed on the downstream side (upward in the drawing) adjacent to the drive roller 21, and a secondary transfer roller 26 that is in pressure contact with the transfer auxiliary roller 25 via the transfer belt 8. It consists of and.

  A belt cleaner 27 is disposed on the transfer belt 8. As shown in an enlarged view in FIG. 3B, the belt cleaner 27 includes a squeeze sheet 27a that contacts the surface of the transfer belt 8 that is stretched around the driven roller 22 and a cleaning blade 28.

  The squeeze sheet 27a is made of an elastic thin film sheet, and allows the waste toner remaining on the surface of the transfer belt 8 to pass through, but prevents the waste toner from scattering from the belt cleaner 27 to the outside.

The waste toner that has passed through the squeeze sheet 27a is scraped off at the tip of the cleaning blade 28 that presses against the surface of the transfer belt 8 in the counter direction and is removed downward.
Below the belt cleaner 27, a recovery member 27b including a conveying screw that conveys the removed waste toner from the near side of the sheet to the depth direction is provided.

  A waste toner collection container 29 is detachably disposed adjacent to the belt cleaner 27 from the left to the bottom. The waste toner collected by the collection member 27b is sent to a waste toner collection container 29 connected to the collection member 27b on the back side of the sheet.

  The toner supply unit 4 includes four toner supply containers 20 (20y, 20m, 20c, and 20k) that are detachably disposed above the upper running unit surface 8a of the transfer belt 8. As described above, the four toner supply containers 20 contain yellow (Y), magenta (M), cyan (C), and black (K) toners.

  These four toner replenishing containers 20 are hidden behind the opposite side of the transfer belt unit 3 in FIG. 3 (a) but are not visible through the toner supply paths that follow the toner supply ports of the mounting portions. The developing unit 14 of the forming unit 9 is connected.

  Although not particularly shown, the toner supply unit 4 is held on the frame of the printer 1 main body through a mounting unit so that it can be raised and lowered from the printing execution position shown in FIG. 3A to a maintenance position above it. ing.

  The paper feed unit 5 includes two paper feed cassettes 30 (30a, 30b) arranged in two upper and lower stages. A paper take-out roller 31, a feed roller 32, a separating roller 33, and a standby conveyance roller pair 34 are disposed in the vicinity of the paper feed opening (right side in the figure) of the two paper feed cassettes 30, respectively.

  In the paper conveyance direction (vertical upward direction in the drawing) of the standby conveyance roller pair 34, the above-described secondary transfer portion 24 to the paper by the transfer belt 8, the transfer auxiliary roller 25, and the secondary transfer roller 26 is formed. On the forefront of the transfer belt unit 3 and the four image forming units 9, there is a unit lock cover 40 (shown by a broken line) which will be described later in detail, although it is not shown in FIG. It is arranged.

  A belt-type heat fixing unit 6 is disposed on the downstream side (upper side in the drawing) of the secondary transfer unit 24, and the sheet after fixing is belt-type heat fixing unit further downstream of the belt-type heat fixing unit 6. A pair of unloading rollers 36 that unloads the sheet 6 and a pair of discharge rollers 38 that discharge the unloaded sheets to a sheet discharge tray 37 formed on the upper surface of the apparatus are disposed.

  The conveyance unit 7 for double-sided printing also serves as an opening / closing member whose outer surface (right outer surface in the drawing) opens or shields the inside of the printer 1 from the side surface to the outside.

  This duplex printing transport unit 7 has a start return path 39a that branches rightward in the figure from just before the paper discharge roller pair 38, an intermediate return path 39b that bends downward, and a left lateral direction opposite to the above. Thus, a return path 39 including a terminal return path 39c for finally inverting the return sheet is provided.

  In the middle of the return path 39, five pairs of return rollers 41 (41a, 41b, 41c, 41d, 41e) are arranged. The exit of the end return path 39 c joins the conveyance path to the pair of standby conveyance rollers 34 corresponding to the sheet feeding cassette 30 b below the sheet feeding unit 5.

  FIG. 4 is an external perspective view of the printer 1. As shown in FIG. 4, the printer 1 includes a front door 42 on the front side. Below the front door 42, two paper feed cassettes 30 a and 30 b shown in FIG. 3A are attached to the front of the apparatus main body 1 by a handle 43 so as to be insertable / removable.

  In addition, the printer 1 includes an opening / closing member 45 having a handle 44 at the upper part on the right side surface. The open / close member 45 is integrated with the duplex printing conveyance unit 7 shown in FIG. An operation panel unit 46 having a display unit and an input operation unit is disposed on the upper right side of the printer 1. Further, on the left side of the operation panel 46, a paper discharge tray 37 shown in FIG.

  As shown in FIG. 3A, the printer 1 does not directly transfer a toner image to a sheet, but transfers a transfer belt 8 to a sheet that is vertically conveyed by a standby conveyance roller pair 34 to a secondary transfer unit. In this method, the toner image is transferred via the sheet, and the sheet is further conveyed in the vertical direction to fix the transferred toner image on the sheet.

  Therefore, it is possible to cope with a maintenance process for recovering from a problem such as a paper jam occurring in the paper transport path by simply opening the right opening / closing member 45 shown in FIG. In other words, problems such as paper jams do not occur in the arrangement section of the kits.

  The operation of attaching and detaching consumables such as kits such as the transfer belt unit 3 and the image forming unit 9 shown in FIG. 3A is performed by opening the front door 42 shown in FIG. 4 and then the unit shown in FIG. The lock cover 40 is opened, and the kits are configured to be exchanged in the longitudinal direction (front door direction).

  By the way, the toner image formed on the photosensitive drum 10 is transferred (primary transfer) to the lower running portion surface 8b of the transfer belt 8 by the primary transfer roller 23 that is pressed through the transfer belt 8 based on the transfer electric field. The Then, the transfer belt 8 conveys the toner image to the secondary transfer unit 24. The secondary transfer unit 24 includes a transfer auxiliary roller 25 adjacent to the drive roller 21 and a secondary transfer roller 26 that is in pressure contact with the transfer belt 8, and transfers the transfer by applying a transfer voltage to the secondary transfer roller 26. The toner image on the belt 8 is transferred (secondary transfer) to the paper.

  During such an image forming process, the toner on the photosensitive drum 10 or the transfer belt 8 is not transferred to the 100% transfer belt 8 or the paper in the primary transfer or the secondary transfer. Accordingly, in the subsequent image forming process, residual toner reaches the cleaning blade provided on the cleaner 11 on the downstream side of the primary transfer and the secondary transfer and the cleaning blade 28 of the belt cleaner 27. As described above, this lubricating component contributes to the improvement of the slidability of the tip of the cleaning blade. In view of the fact that the slidability of the cleaning blade cannot be ensured with only the untransferred toner generated during the normal image forming process, the toner is positively applied.

  The printer 1 according to the embodiment of the present invention is also configured to positively apply toner in order to ensure the slidability of such a cleaning blade.

  That is, in the printer 1 of the present embodiment, the lubricating toner for protecting the cleaning blade is exposed at a timing different from the time when the normal toner image to be output on the printing paper is formed on the photosensitive drum 10. It is controlled to supply the body drum 10 and the transfer belt 8.

  As the timing of the toner for lubrication, for example, the timing between the output processing of the printing paper is set every time the output processing to the printing paper is performed for one page or several pages.

  Specifically, when the supply timing of the lubricating toner arrives, for example, the charging roller 12, the optical writing head 13, the primary transfer roller 23, and the secondary transfer roller 26 that have been driven and controlled so as to form an image. The driving is stopped, and when the portion where the charging by the charging roller on the photosensitive drum 10 is switched off passes the developing position by the developing roller 15 for a predetermined time, the rotational driving of the photosensitive drum 10 is stopped and the next printing paper Wait for output processing.

  As a result, the toner image band pattern is forcibly developed and discharged in the developing position passage range on the photosensitive drum 10. Then, when the rotational driving of the photosensitive drum 10 and the transfer belt 8 is resumed based on the output processing of the next printing paper, the toner image band pattern is collected by the cleaner 11 and the belt via the transfer belt 8. It is controlled to be collected in the cleaner 27.

  Note that the area of the toner image band pattern, that is, the amount of toner developed and transferred, is adjusted according to the page for the output process to the printing paper.

  However, this alone cannot completely prevent a buckling phenomenon from occurring at the tip of the cleaning blade 28 that is in pressure contact with the image carrier, particularly the transfer belt 8, depending on printing conditions such as continuous printing.

  Therefore, in the present invention, as described later, a special configuration that continuously acts the toner as the lubricant is adopted.

  FIG. 5A is a perspective view showing a state in which the transfer belt unit 3 and the four image forming units 9m, 9c, 9y, and 9k are mounted in the apparatus main body 1 with the unit lock cover 40 removed. is there. FIG. 5B is a perspective view showing a unit lock cover that prohibits removal of the transfer belt unit 3 and the four image forming units 9m, 9c, 9y, and 9k.

  As shown in FIG. 5 (a), the transfer belt unit 3 includes a front frame 59a and a rear frame 59b, and a drive roller 21 and a driven roller 22 (see FIG. 3 (a)) held by both frames. And a transfer belt 8 supported so as to circulate and move. A discharge port cap 61 that opens and closes the waste toner discharge port is disposed at the back end of the belt cleaner 27.

  Here, at the center of the front frame 59 a of the transfer belt unit 3, a unit pull-out handle 301 that is used when the transfer belt unit 3 is attached to and detached from the apparatus main body 1 is formed. Further, above the upper surface of the transfer belt 8, two handle portions 302a and 302b made of a plate-like member are disposed so as to be passed between the front frame 59a and the rear frame 59b.

  The two handles 302a and 302b have handles 303a and 303b whose ends are slidable for carrying the transfer belt unit 3 when the transfer belt unit 3 is attached to and detached from the main body of the printer 1 or outside the main body of the printer 1. Each is attached.

  Note that a brush member 304 serving as a main part of the present invention, which will be described in detail later, is disposed on the back surfaces of the two handle portions 302a and 302b.

  Below the transfer belt unit 3, four image forming units 9 (9m, 9c, 9y, 9k) are arranged. Each of the four image forming units 9 is provided with a handle 65 that is picked up when the image forming unit 9 is attached to or detached from the main body of the printer 1.

  In FIG. 5A, the contact state between the toner image transfer surface on the lower surface of the transfer belt 8 and the photosensitive drum 10 of the image forming unit 9 is not visible in the figure but constitutes a belt position control mechanism. The separation cam lever 57 is in the vertical position and is set to the full color printing mode or the monochrome printing mode.

  In this state, the unit lock cover 40 shown in FIG. 5B (see also FIG. 3A) is unlocked, the unit lock cover 40 is opened, and the unit pull-out handle 301 is placed on the transfer belt. If the unit 3 is pulled out in front of the main body of the printer 1, the lower surface of the transfer belt 8 and the upper surface of the photosensitive drum 10 are in sliding contact with each other, and both are damaged.

  Therefore, the separation cam lever 57 is rotated 90 degrees by hand counterclockwise from the vertical position, and the transfer belt 8 is set to the all non-transfer mode in which all the four primary transfer rollers 23 are separated from the photosensitive drum 10. The transfer belt unit 3 must be pulled out.

  FIG. 5B is a diagram specifically showing a relationship with the unit lock cover 40 disposed on the front surface in the state of FIG. A lock cover opening / closing knob 66 is disposed near the right end of the unit lock cover 40. The unit lock cover 40 is engaged with a body frame of the printer 1 (not shown) to control the opening and retreating of the unit lock cover 40 (in FIG. 5B, the open / close lock claws 67a and 67b are on the upper side. Opening and closing lock claws 67a and 67b that protrude and engage with the main body frame of the printer 1 (not shown) are provided. A knob 66 and a link mechanism are configured.

  The lock cover opening / closing knob 66 is rotatably attached to a cover lock position shown in FIG. 5B and a cover lock release position rotated 90 degrees counterclockwise as shown by an arrow b.

  When the lock cover opening / closing knob 66 is rotated to the cover lock position and the opening / closing of the unit lock cover 40 is prohibited, the transfer belt unit 3 and the four image forming units 9 can be removed from the apparatus main body 1. Forbidden by 40.

  In this example, the inside of the lock cover opening / closing knob 66 is formed in a cavity, although not particularly shown. However, a plate-like body having a radius extending from the knob shaft to the inner peripheral surface is disposed at a predetermined location.

  When the lock cover opening / closing knob 66 is in the cover lock position as shown in FIG. 5B, the plate-like body is in a position to contact the right side surface of the separation cam lever 57 in the vertical position shown in FIG. 5A. It is formed corresponding to. That is, the separation cam lever 57 shown in FIG. 5A enters the inside of the lock cover opening / closing knob 66 in the state shown in FIG. 5B.

  When the user or maintenance worker takes out the transfer belt unit 3 from the apparatus main body 1 in order to perform maintenance or inspection of the transfer belt unit 3, first, the front door 42 shown in FIG. 4 is opened. Next, to unlock the unit lock cover 40 shown in FIGS. 3A and 5B, the lock cover opening / closing knob 66 is twisted 90 degrees counterclockwise.

  As a result, the lock of the unit lock cover 40 is released (the open / close lock claws 67a and 67b are retracted downward) so that the unit lock cover 40 can be opened, and the separation cam lever 57 is moved vertically in conjunction with the lock cover open / close knob 66. Rotate 90 degrees counterclockwise from the position (FIG. 1A, which will be described later with the transfer belt unit 3 taken out from the main body of the printer 1, shows that the separation cam lever 57 is in the horizontal position. )

  As a result, the user or maintenance worker immediately takes the unit pull-out handle 301 without paying attention to the engagement state of the transfer belt unit 3 and the photosensitive drum 10 of the image forming unit 9, and transfers the transfer belt unit. 3 can be taken out from the apparatus main body 1.

  FIG. 1A is an external perspective view showing the transfer belt unit 3 shown in FIG. FIG. 1 (b) is a top view showing the transfer belt unit with the handle portion taken out, FIG. 1 (c) is a bottom view of the handle portion taken out, and FIG. 1 (d) shows the handle portion. It is a side view in the longitudinal direction of a cleaning blade lubricity adjusting member (brush member) according to one embodiment of the present invention attached.

  In the transfer belt unit 3 shown in FIG. 1 (a), of the two handle portions 302a and 302b provided along the upper running portion surface 8a of the transfer belt 8, on the back surface of the right handle portion 302a in the drawing. 1 (c) and FIG. 1 (d), the toner as a lubricant is continuously acted on the cleaning blade 28 of FIG. 3 (b) via the toner scattering prevention sheet 305a. Accordingly, the brush member 304 of the present invention is disposed as a cleaning blade lubricity adjusting member.

  As shown in FIG. 1D, the brush member 304 is attached to the lower surface of the handle portion 302a, to which the toner scattering prevention sheet 305a is attached with the double-sided tape 305b, via the double-sided tape 304c. .

  In this embodiment, the brush member 304 has a length of about 320 mm and a width, for example, in which a brush 304a made of a PET pile having a fineness of 280T (decix) and a density of 80 KF / in ↑ 2 is planted on the brush base sheet 304b. It has a rectangular parallelepiped shape of about 16 mm and a height of about 5 mm.

  FIG. 1E is a diagram for explaining the operation of the brush member 304 of the present embodiment. As shown in FIG. 1 (e), the brush member 304 is such that the tip of the brush bristle bites into the D dimension (about 1.85 mm) with respect to the upper running portion surface 8b of the belt 8 at the position of the handle portion 302a. Light pressure contact with a moderate contact pressure.

  As a result, the residual toner TB conveyed from the upstream side is temporarily blocked and acclimatized, and is conveyed downstream as a minute amount of residual toner TS.

  As a result, the toner that reaches the cleaning blade 28 in FIG. 3B and exhibits a lubricating action becomes uniform and continuous, and the buckling phenomenon at the tip of the cleaning blade 28 can be reliably prevented, compared to the conventional method. It was confirmed that the cleaning blade has an extremely long service life.

  In the above-described embodiment, the brush member 304 has been described as an example of a rectangular parallelepiped shape along the handle portion 302a, but the shape can be variously modified.

  For example, FIG. 2 is a bottom view of a brush member 306 illustrating another embodiment of the present invention. The brush member 306 has a central portion 306a in the longitudinal direction convex toward the upstream in the moving direction of the upper running portion surface 8a of the transfer belt 8 from both ends. With this configuration, when the residual toner TB conveyed from the upstream side is temporarily blocked and habituated, it acts to be distributed to both ends as indicated by arrows. As a result, generally, the print output tends to be biased toward the central portion, and accordingly the amount of residual toner TB is biased toward the central portion, so that the residual toner TS downstream can be made more uniform.

  In the above embodiment, the brush member 304 has been described as being disposed only at one position of the handle portion 302a. However, by attaching the brush member 304 to the handle portion 302b, the life of the brush member 304 can be extended and the residual toner TS can be removed. It is also possible to achieve further uniformization.

Although several embodiments of the present invention have been described, the present invention is included in the invention described in the claims and the equivalents thereof. Hereinafter, the invention described in the scope of claims of the present application will be appended.
[Appendix 1]

A unit frame,
An endless transfer belt which is supported by the unit frame so as to be able to circulate through a driving roll and a follower roll, and which moves facing an image forming unit disposed in an image forming apparatus that forms an image using toner; ,
A cleaning blade that is pressed against the transfer belt and scrapes off the residue containing toner carried on the surface of the transfer belt;
The transfer belt is located on the downstream side in the moving direction from the position facing the image forming portion and upstream in the moving direction from the pressure contact position of the cleaning blade. A handle for attaching to and detaching from the image forming apparatus provided along the surface;
A cleaning blade lubricity adjusting member that is disposed on the handle and is lightly pressed against the surface of the transfer belt to temporarily block the residue;
A transfer belt unit comprising:
[Appendix 2]

2. The transfer belt unit according to appendix 1, wherein the cleaning blade lubricity adjusting member comprises a brush-like member.
[Appendix 3]

3. The transfer belt unit according to claim 2, wherein the lubricity adjusting member is formed such that a central portion in the longitudinal direction is convex toward the upstream in the moving direction of the transfer belt from both ends.
[Appendix 4]

4. The transfer belt according to claim 1, wherein the transfer belt has an upper surface portion and a lower surface portion that are substantially parallel, and the handle portion is provided in the unit frame at two locations along the upper surface portion. Transfer belt unit.
[Appendix 5]

The image forming apparatus includes a primary transfer unit that faces the image forming unit via the transfer belt, and the transfer belt is an intermediate transfer belt that forms a secondary transfer unit with a transfer roller disposed in the image forming apparatus. The transfer belt unit according to any one of appendices 1 to 4, characterized in that:
[Appendix 6]

An image forming apparatus comprising the transfer belt unit according to any one of appendices 1 to 5 in a detachable manner.
[Appendix 7]

And a control unit that controls an image forming operation of the image forming unit, and the control unit maintains lubricity of a pressure contact portion between the cleaning blade and the endless transfer belt after a series of image forming operations using a toner image is completed. 7. The image forming apparatus according to claim 6, wherein the image forming unit is controlled to apply toner onto the endless transfer belt so as to function as a lubricant for the purpose.

  The present invention can be used for extending the life of a transfer belt unit provided with a cleaning blade.

1 Printer (Full-color image forming device)
2 Image forming unit 3 Transfer belt unit 4 Toner supply unit 5 Paper feeding unit 6 Belt fixing unit 7 Double-sided printing transport unit 8 Transfer belt 8a Upper running unit surface 8b Lower running unit surface 9 (9m, 9c, 9y, 9k) Image forming unit 10 Photosensitive drum 11 Cleaner 12 Charging roller 13 Optical writing head 14 Developer 15 Developing roller 16 Unit housing 17 Bulkhead 18 First stirring and conveying screw 19 Second stirring and conveying screw 20 (20y, 20m, 20c 20k) Toner supply container 21 Drive roller 22 Driven roller 23 (23y, 23m, 23c, 23k) Primary transfer roller 24 Secondary transfer unit 25 Transfer auxiliary roller 26 Secondary transfer roller 27 Belt cleaner 27a Squee sheet 27b Recovery member 28 Cleaning blade 29 Waste toner times Container 30 (30a, 30b) Paper feed cassette 31 Paper take-out roller 32 Feed roller 33 Rolling roller 34 Standby transport roller pair 36 Transport roller pair 37 Paper discharge tray 38 Paper discharge roller pair 39 Return path 39a Start return path 39b Intermediate return path 39c End return path 41 (41a, 41b, 41c, 41d, 41e) Return roller pair 40 Unit lock cover 42 Front door 43, 44 Handle 45 Opening / closing member 46 Operation panel part 57 Separation cam lever 59a Front frame 59b Rear frame 61 Discharge port cap 65 Handle 66 Lock cover open / close knob 67 Cover open / close lock claw 301 Unit drawer handle 302 (302a, 302b) Handle 303 (303a, 303b) Handle 304 Brush member (cleaning blade lubricity adjusting member)
304a Brush 304b Brush base sheet 304c Double-sided tape 305a Toner scattering prevention sheet 305b Double-sided tape

Claims (7)

A unit frame,
An endless transfer belt which is supported by the unit frame so as to be able to circulate through a driving roll and a follower roll, and which moves facing an image forming unit disposed in an image forming apparatus that forms an image using toner; ,
A cleaning blade that is pressed against the transfer belt and scrapes off the residue containing toner carried on the surface of the transfer belt;
The transfer belt is located on the downstream side in the moving direction from the position facing the image forming portion and upstream in the moving direction from the pressure contact position of the cleaning blade. A handle for attaching to and detaching from the image forming apparatus provided along the surface;
A cleaning blade lubricity adjusting member that is disposed on the handle and is lightly pressed against the surface of the transfer belt to temporarily block the residue;
A transfer belt unit comprising:   The transfer belt unit according to claim 1, wherein the cleaning blade lubricity adjusting member is a brush-like member. The transfer belt unit according to claim 2, wherein the lubricity adjusting member is formed such that a central portion in the longitudinal direction is convex toward the upstream in the moving direction of the transfer belt from both ends.   4. The transfer belt according to claim 1, wherein the transfer belt has an upper surface portion and a lower surface portion that are substantially parallel to each other, and the handle portion is provided in the unit frame at two locations along the upper surface portion. The transfer belt unit according to Item. The image forming apparatus includes a primary transfer unit that faces the image forming unit via the transfer belt, and the transfer belt is an intermediate transfer belt that forms a secondary transfer unit with a transfer roller disposed in the image forming apparatus. The transfer belt unit according to any one of claims 1 to 4, wherein:   An image forming apparatus comprising the transfer belt unit according to claim 1 detachably. And a control unit that controls an image forming operation of the image forming unit, and the control unit maintains lubricity of a pressure contact portion between the cleaning blade and the endless transfer belt after a series of image forming operations using a toner image is completed. 7. The image forming apparatus according to claim 6, wherein the image forming unit is controlled so as to apply toner onto the endless transfer belt so as to function as a lubricant for the purpose.