JP4114841B2 - Developer / Printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a developing device used in the printing field such as offset printing, stencil printing, DTP printing, short run printing, and a printing apparatus using the same.
[0002]
[Prior art]
For example, in an offset printing machine, a printing plate is wound around an outer peripheral surface of a printing drum (plate cylinder), and printing data is written on the printing plate on the wound printing drum by a laser writing device, and the plate is made. Ink is supplied by a developing device and developed, and the developed ink image is transferred to printing paper.
As a printing plate, generally, a PS plate having a higher price per plate than a stencil sheet is used.
For color printers, the ink image formed on each printing drum is transferred to a transfer blanket drum individually corresponding to each printing drum, and the transferred ink image is sequentially superimposed on the printing paper to obtain a color image. It has become.
[0003]
[Problems to be solved by the invention]
In order to achieve miniaturization, compactness, and space saving in the color printing apparatus, the present applicant arranges a vertically long transfer means (transfer belt system) at the center of the apparatus, and print drums and developing devices for each color on both sides thereof. A configuration in which one transfer means is shared by arranging them symmetrically has been proposed (for example, Japanese Patent Application No. 11-147624).
Briefly describing this, as shown in FIG. 11, printing drums 102, 104, 106, and 108 of the respective colors are arranged on both sides of the vertically long transfer means 100, and the respective colors are individually associated with these printing drums. Developing devices 110, 112, 114, and 116 containing the inks are arranged.
The color ink images formed by the printing drums 102, 104, 106, and 108 are sequentially superimposed and transferred onto the transfer belt of the transfer unit 100, and the superimposed ink images are collectively transferred onto the printing paper 120 by the transfer roller 118. Is.
[0004]
Each developing device includes a developing roller 122 that supplies ink to a printing plate on a printing drum and an ink that supplies ink to the developing roller 122, as shown in FIG. The magazine 124, the blade holding means 128 provided so as to be rotatable about the shaft 126, the blade 130 held by the blade holding means 128 for adjusting the thickness of the ink on the developing roller 122, and the blade holding means 128 are rotated. A driving source 132 for adjusting the blade 130 (adjustment of ink thickness) with respect to the developing roller 122 by moving is provided. The blade holding means 128 also functions as an ink reservoir member.
A swing roller 134 is provided on the downstream side of the blade 130 in the rotation direction of the developing roller 122 so as to make the ink layer whose thickness is constant by the blade 130 more uniform.
The oscillating roller 134 is rotatably held at the tip of a dog-legged arm 138 that rotates about a shaft 136, and the urging force of the spring member 140 that is locked to the other end of the arm 138. Is pressed against the developing roller 122 with a predetermined pressure.
[0005]
As shown in FIGS. 12 and 13, the components of each developing device are shared in order to reduce manufacturing costs and facilitate replacement. In FIG. 11, the rotation direction of the developing roller 122 in each developing device is the same, but the rotating direction of the developing roller 122 when viewed from the developing device itself is opposite on the left side and the right side.
That is, FIG. 14 is a view of the developing device 114 shown in FIG. 13 as viewed from the back side, but the rotation direction of the developing roller 122 is opposite to that in the case of FIG. Accordingly, the blade 130 in the developing device 114 is held on the opposite side of the blade holding means 128 in order to obtain a good counter function for the developing roller 122.
This relationship is the same between the developing device 110 located on the left side and the developing device 116 located on the right side in FIG.
[0006]
However, it has been found that there is a new problem in such a common configuration of developing devices.
That is, in the developing devices 114 and 116 located on the right side in FIG. 11, as shown in FIG. 13, the load F applied to the blade 130 by the rotation of the developing roller 122 is an axis that is the rotation center of the blade holding unit 128. It faces 126 side.
For this reason, it has been found that there is a possibility that chatter vibrations occur due to the load F applied to the blade 130 and the drag force from the shaft 126, resulting in density unevenness. The same applies to the developing roller 116 located on the right side.
In the developing devices 112 and 110 located on the left side, as shown in FIG. 12, the load F applied to the blade 130 by the rotation of the developing roller 122 is away from the shaft 126 that is the rotation center of the blade holding means 128. Therefore, the above problem does not occur.
[0007]
Accordingly, the main object of the present invention is to provide a developing device and a printing apparatus including the developing device that can eliminate the vibration problem without increasing the cost while keeping the parts as common as possible. To do.
Another object of the present invention is to provide a developing device that can achieve both the degree of freedom of arrangement and the common use of its components, and that can contribute particularly to a compact color structure and cost reduction, and a printing apparatus equipped with the developing device. .
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, a developing roller that supplies ink to a printing plate wound on a plate cylinder, an ink supply source that supplies ink to the developing roller, and A blade for adjusting the thickness of the ink on the developing roller to a constant level, a blade holding means for holding the blade and having a rotation fulcrum, and capable of rotating and contacting the developing roller by a rotating operation; and driving the blade holding means And a driving source for bringing the blade into and out of contact with the developing roller, and a rotation fulcrum of the blade holding means is provided upstream of a contact point between the developing roller and the blade in the rotation direction of the developing roller.The blade holding means has two rotation fulcrums where the other is positionally free when one is selected, and the rotation direction of the developing roller changes depending on the arrangement state of the developing device. Rotation fulcrum satisfying the position condition corresponding to can be selected, Is adopted.
[0009]
According to a second aspect of the present invention, in the configuration according to the first aspect, the blade holding means has a function as an ink reservoir member that temporarily stores ink from the ink supply source.
[0010]
According to a third aspect of the present invention, in the configuration according to the first or second aspect, a tangential direction of a rotation locus of a tip of the blade at a contact point between the developing roller and the blade is directed toward a substantially rotation center of the developing roller. It has the structure of being.
[0011]
According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, the blade is bent by the rotational load of the developing roller at a central portion in the longitudinal direction of the blade of the blade holding unit. The structure that the reinforcement member which prevents is provided is taken.
[0012]
According to a fifth aspect of the present invention, in the configuration according to any one of the first to fourth aspects, the blade is formed of a plate material, and the tip of the contact side with the developing roller has only one side. The wedge-shaped tip is formed in a wedge-like shape, and the tip of the wedge-shaped tip is formed on a flat surface having a slight width in the rotation direction of the developing roller, and is opposite to the oblique-cut surface of the wedge-shaped tip. The side surface faces the upstream side in the rotation direction of the developing roller.
[0013]
In the invention described in claim 6, in the structure described in claim 5, the width of the flat surface is 0.2 mm or less.
[0014]
According to a seventh aspect of the present invention, in the configuration according to one of the first to sixth aspects, the tip of the blade on the contact side with the developing roller does not have an unevenness of 2 μm or more. ing.
[0015]
  In the invention according to claim 8, in the developing device according to one of claims 1 to 7,The blade holding position of the blade holding means is provided at two appropriate positions corresponding to the two rotation fulcrums and so that one blade can be shared., Is adopted.
[0016]
  In the invention of claim 9, the claim1 to 8In the described developing device,The blade holding means is driven by the drive source by a screw feed method., Is adopted.
[0017]
  In invention of Claim 10,Printing device for forming ink image by supplying ink to printing plate wound on plate cylinder by developing device and transferring the ink image to printing paperInThe developing device according to claim 1, wherein the developing device is a developing device according to claim 1., Is adopted.
[0019]
Embodiment
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a printing apparatus having a developing device according to an embodiment of the present invention, and shows an example of full-color correspondence using a heat-sensitive and water-repellent printing plate.
The printing apparatus includes four plate cylinders 2 and a loop-shaped primary transfer means 4 that is provided between the plate cylinders 2 so as to be symmetrically positioned on the left and right sides and that extends vertically in the vertical direction. And printing data on the plate cylinder 2 on a heat-sensitive and water-repellent printing plate 5 (hereinafter simply referred to as plate 5) provided near the upper part of each plate cylinder 2 and wound around the outer peripheral surface of the plate cylinder 2. Thermal writing means 6 for writing, developing devices 8 a, 8 b, 8 c, 8 d that are provided on the side of each plate cylinder 2 and supply ink of the respective colors to the plate 5, paper feeding means 10, and each plate cylinder The secondary transfer means 12 for transferring the ink (superimposed ink image) transferred from 2 to the primary transfer means 4 to the printing paper P fed from the paper feed means 10, and the primary transfer means 4 after the transfer. The cleaning means 14 for cleaning the transfer belt 28 and the transferred printing paper P A conveying means 16 for transporting the Chakushudan 18, the discharge means 20 for discharging the fixed toner image of the print paper P, and a discharged paper receiving section 22 or the like.
The plate cylinder 2, the thermal writing means 6 and the developing device 8 constitute one image forming unit, and this image forming unit is arranged symmetrically around the primary transfer means 4 for each ink color.
[0020]
As described above, in a conventional color printing machine, an ink image formed on each printing drum is transferred to a transfer blanket drum individually corresponding to each printing drum, and the transferred ink image is sequentially transferred onto the printing paper. The color image was obtained by superimposing them.
On the other hand, as described above, in the printing apparatus according to the present embodiment, a plurality of image forming units are arranged around the vertically long primary transfer unit 4 and the primary transfer unit 4 is shared.・ Compact and space saving can be achieved.
Further, in the present embodiment, since the heat-sensitive and water-repellent printing plate 5 as low as the stencil sheet is used as the printing plate and the writing means is a heat-sensitive type, a low price can be realized.
The image forming unit provides full color basic colors (process colors), for example, yellow (Y), magenta (M), cyan (C), and black (Bk) for characters and inking. There are four combined.
[0021]
Each plate cylinder 2 is rotationally driven by a drive means (not shown) with the rotation shaft 24 as a rotation center, and a plate supply means 26 for supplying and collecting the plate 5 is provided therein.
The plate supply means 26 includes a plate supply roller 26a around which the unused plate 5 is wound in a roll shape, a plate collection roller 26b that winds up the used plate 5, and a roller drive source (not shown). The unused plate 5 fed out from the plate supply roller 26a exits from a slit-shaped opening 2a formed in the plate cylinder 2 and extends in the direction of the rotation shaft 24, and is wound around the outer peripheral surface of the plate cylinder 2 through the opening 2a. The mounting form is such that it returns to the inside of the plate cylinder 2 and is locked to the plate collection roller 26b.
When the predetermined number of prints is completed, the plate feeding means 26 is driven to replace the used plate 5 wound around the outer peripheral surface of the plate cylinder 2 with a new plate 5. For example, control is performed to rotate the plate collection roller 26b by a predetermined amount. The used plate 5 is collected in the plate cylinder 2 by the rotation of the plate collecting roller 26b, and a new plate 5 is supplied to the surface of the plate cylinder 2 by the driven rotation of the plate supply roller 26a accompanying this collecting operation.
[0022]
Each developing device 8a, 8b, 8c, 8d supplies printing ink of each color (yellow, magenta, cyan, black) to the plate 5 on which printing data is written by the thermal writing means 6 on the plate cylinder 2. Device. Details of the configuration of each developing device 8a, 8b, 8c, 8d will be described later.
[0023]
The primary transfer means 4 includes a rubber transfer belt 28 for transferring the ink image formed on each plate cylinder 2 and temporarily receiving it, a pressing mechanism 30 for pressing the transfer belt 28 against the plate cylinder 2 during transfer, and the like. have.
The primary transfer means 4 will be described in detail with reference to FIG. The transfer belt 28 is basically stretched between the driving roller 32 and the driven roller 34.
The pressing mechanism 30 is provided inside the transfer belt 28 so as to correspond to each plate cylinder 2 individually. Each pressing mechanism 30 includes a lever 38 that is rotatably supported by a shaft 36 that is fixed to a side plate (not shown), a platen roller 40 that is rotatably provided at one end of the lever 38, and the platen roller 40 that transfers the platen roller 40. A spring (not shown) that constantly applies an urging force to the lever 38 so as to press the belt 28 against the plate cylinder 2, a cam follower 42 provided at the other end of the lever 38, and the cam follower 42 abut on the cam 38 to swing the lever 38. A cam 44 or the like is provided. The cam 44 is driven by a drive source (not shown) according to the transfer timing.
[0024]
1 and 2 show a non-transfer state of each pressing mechanism 30. When the cam 44 of the pressing mechanism 30 corresponding to the plate cylinder 2 to be transferred is driven at a predetermined timing, the lever 38 is a spring. The platen roller 40 presses the transfer belt 28 against the plate cylinder 2 by rotating with an urging force. By this pressing, the ink image formed on the plate 5 on the plate cylinder 2 is transferred onto the transfer belt 28. Nitrile rubber, urethane rubber, or the like can be used as the rubber that is the material of the transfer belt 28. The surface of the transfer belt 28 has a surface roughness set in consideration of conditions such as the transfer of ink from the plate cylinder 2 and the transfer of ink to the printing paper P.
[0025]
The ink images of the respective colors are transferred to the same position on the transfer belt 28 and transferred onto the printing paper P by the secondary transfer means 12 described later.
In conventional color printing machines, ink is stacked on the printing paper in sequence, which depends on the printing paper conveyance accuracy, and is affected by the expansion and contraction of the printing paper. Met. On the other hand, in the configuration of the present embodiment, the ink images are superimposed on the transfer belt 28 that can be easily aligned, and transferred to the printing paper P in a lump, so that measures against color misregistration are also accurate. It is possible to improve color printing with stable quality.
[0026]
As described above, the primary transfer unit 4 superimposes a plurality of color ink images on the transfer belt 28 and transfers them onto the printing paper P at a time. This is the reverse of the ink transfer order on 28, which is the final image.
In general, when performing color printing, a color image can be sharpened and a printed image with excellent brightness and the like can be obtained by placing dark ink on the printing paper and overlaying thin ink thereon.
For this reason, the order of transferring the plurality of colors of ink to the transfer belt 28 is required to be transferred from the reverse thin ink as usual, and the dark ink needs to be transferred later. As a specific example, if ink is transferred onto the transfer belt 28 in the order of yellow (Y), cyan (C), magenta (M), and black (Bk), and this is transferred onto the printing paper P at once, Since transfer is performed in the order of Bk, M, C, and Y on the printing paper P, the light color Y is the top on the printing paper P, and a clear and bright printed image is obtained. In this case, the developing device 8a corresponds to yellow, the developing device 8b corresponds to cyan, the developing device 8c corresponds to magenta, and the developing device 8d corresponds to black.
[0027]
The transfer (secondary transfer) of the superimposed ink image formed on the transfer belt 28 is performed by pressing the printing paper P against the transfer belt 28 by the secondary transfer unit 12.
The separation of the printing paper P after the secondary transfer from the transfer belt 28 employs a curvature separation method. That is, as shown in FIG. 2, a small-diameter tension roller 46 is provided in the vicinity of the drive roller 32, and the curvature of the transfer belt 28 is very large in this portion. When the printing paper P arrives at the separation portion, the printing paper P is automatically separated without being wound around the transfer belt 28 due to its strength. Since no special separation means such as a separation claw for separating the printing paper P is required, it is possible to promote cost reduction and downsizing from this viewpoint.
[0028]
As shown in FIG. 1, the paper supply means 10 has a paper supply table 48 on which the print paper P is stacked, a paper supply roller 50, a separation roller 52, and the like. Separate and feed.
After the printing paper P fed from the paper feeding means 10 is corrected by the registration roller pair 54 to be obliquely displaced, the predetermined position in the transport direction of the printing paper P and the leading edge of the ink image on the transfer belt 28 coincide. Is sent to the nip portion between the primary transfer means 4 and the secondary transfer means 12 at the timing of
[0029]
The secondary transfer unit 12 includes an arm 58 that is rotatably supported by a shaft 56 that is fixed to a side plate (not shown), a press roller 60 that is rotatably supported by one end of the arm 58, and the press roller 60 that performs transfer. A spring 62 that constantly applies an urging force to the arm 58 so as to abut on the belt 28 and an abutment on the other end of the arm 58, and the arm 58 swings so that the press roller 60 contacts and separates from the transfer belt 28. A cam 64 is provided. The cam 64 is driven by a driving source (not shown) according to the feeding timing of the registration roller pair 54.
[0030]
The cleaning unit 14 includes a casing 66, a cleaning blade 68 that contacts the surface of the transfer belt 28 to scrape residual ink, and a transport member 70 that transports ink accumulated in the casing 66 to a waste ink tank (not shown). ing.
A backup roller 72 for improving the scraping action of the cleaning blade 68 is provided at a position facing the cleaning blade 68 with the transfer belt 28 interposed therebetween.
[0031]
The printing paper P separated from the transfer belt 28 is conveyed by the conveying unit 16 and enters the fixing unit 18. The conveying means 16 may be of a type that is sucked and conveyed by a fan suction action.
The fixing unit 18 is for firmly fixing the freshly dried ink on the printing paper P to the printing paper P, and includes a fixing roller 74 and a pressure roller 76 that is in pressure contact with the fixing roller 74. . In fixing the printing ink, the fixing roller 74 is a roller made of an oil-resistant rubber (for example, silicone rubber or fluorine rubber) that absorbs the solvent of the printing ink. If a heat source (electric heater, halogen lamp, etc.) for promoting fixing is provided inside the fixing roller 74, better fixing can be achieved.
After the fixing, the printing paper P is nipped and transported by a paper discharge means 20 including a driving roller and a driven roller, and is discharged and stacked on a paper discharge receiving means 22 such as a paper discharge tray.
[0032]
  Next, each developing device 8a, 8b, 8c, 8d will be described in detail.
  FIG. 3 shows the developing devices 8a and 8b located on the left side in FIG. The developing devices 8a and 8b include a developing roller 80 for supplying ink to the plate 5 on the plate cylinder 2, an ink magazine 81 as an ink supply source for supplying ink to the developing roller 80, and two rotation fulcrums 82a and 82b. A blade holding means 83 provided so as to be rotatable about any one of them, a blade 84 held by the blade holding means 83 and adjusting the ink thickness on the developing roller 80 to be constant, A screw feed type drive source 85 for adjusting the blade 84 (adjustment of ink thickness) with respect to the developing roller 80 by rotating the blade holding means 83.9) And a casing 86 for covering them.
  As described above, the members responsible for the necessary functions of ink are concentrated on the upper portion of the developing roller 80, thereby achieving downsizing and simplification.
  Note that the ink leveling configuration on the downstream side of the blade 84 corresponding to the swing roller 134 and the like shown in FIG. 12 is omitted in order to avoid complication of the drawing. The same applies to the right developing devices 8c and 8d described later.
[0033]
  The ink magazine 81 is formed in a cylindrical shape, and an ink supply port 81 a for supplying ink to the blade holding unit 83 is provided in the lower part thereof. In addition, an agitator for stirring the ink is disposed in the center of the ink magazine 81.81bIs provided.
  The blade holding unit 83 includes a box-shaped ink reservoir 87 having an upper and lower opening for temporarily storing ink supplied from the ink magazine 81, and arms 88a and 88b provided integrally with the ink reservoir 87. have. A pivot fulcrum 82a is formed on the arm 88a, and a pivot fulcrum 82b is formed on the arm 88b.
  The ink reservoir 87 has blade holding plates 87a and 87b extending along the axial direction of the developing roller 80, and side walls 87c and 87d. The blade holding plates 87a and 87b extend to both end portions of the developing roller 80, and a width necessary for printing is secured. Therefore, the blade holding means 83 also has a function as an ink reservoir member.
[0034]
The arm portions 88a and 88b extend integrally from the side walls 87c and 87d. An agitator 89 that holds and stirs the ink falling from the ink magazine 81 is provided inside the ink reservoir 87.
The blade 84 is attached to a blade holding plate 87b positioned on the downstream side in the rotation direction of the developing roller 80 so that excess ink returns to the ink reservoir 87 by being regulated to a certain thickness. The blade 84 also has the same length as the blade holding plates 87a and 87b.
The drive source 85 includes a motor 90 and a screw shaft 92 fixed to the rotation shaft of the motor 90. The arm portion 88a is provided with a nut member 94 that meshes with the screw shaft 92, and the arm portion 88a is driven in the direction of the arrow by the forward and reverse rotation of the motor 90.
The rotation of the motor 90 is converted into a linear movement with a minute movement, whereby the ink film thickness is adjusted with high accuracy.
[0035]
  In the developing devices 8a and 8b, of the two rotation fulcrums 82a and 82b, the rotation fulcrum 82a (indicated by hatching) located upstream of the contact point S between the development roller 80 and the blade 84 in the rotation direction of the development roller 80 is selected. (Claim 1). The rotation fulcrums 82a and 82b are holes, and the casing 86 is formed with receiving portions (screw holes) for fixing bolt-shaped rotation shafts (not shown) corresponding to the rotation fulcrums 82a and 82b. Has been.
  When the rotation fulcrum 82a is selected, the rotation axis is passed only through the rotation fulcrum 82a and fixed to the receiving portion. On the other hand, the rotation fulcrum 82b is not restrained at all and is free in position (claims).1).
[0036]
With this configuration, the blade holding unit 83 rotates about the rotation fulcrum 82a by the driving force of the drive source 85, and the blade 84 contacts and separates from the developing roller 80 by this rotation operation. The ink thickness is adjusted by adjusting the blade 84 to and away from the developing roller 80, and the density is adjusted.
When density adjustment is input from an operation panel (not shown) of the printing apparatus, control means (not shown) drives the motor 90 corresponding to the adjustment amount.
Since the load F applied to the blade 84 by the rotation of the developing roller 80 is directed away from the rotation fulcrum 82a, chatter vibration does not occur.
[0037]
  FIG. 4 shows the developing devices 8c and 8d located on the right side in FIG. In the developing devices 8c and 8d, since the rotation direction of the developing roller 80 is reversed, the blade 84 is attached to the blade holding plate 87a.8).
  Further, in the developing devices 8c and 8d, the rotation fulcrum 82b (hatched) is satisfied in order to satisfy the condition that “the rotation fulcrum is provided upstream of the contact S between the developing roller 80 and the blade 84 in the rotation direction of the developing roller 80”. Is displayed). When the rotation fulcrum 82b is selected, the rotation axis is passed only through the rotation fulcrum 82b and fixed to the receiving portion, as described above. On the other hand, the rotation fulcrum 82a is not restrained at all and is free in position.
  With this configuration, the blade holding unit 83 rotates about the rotation fulcrum 82b by the driving force of the drive source 85, and the blade 84 contacts and separates from the developing roller 80 by this rotation operation. The ink thickness is adjusted by adjusting the blade 84 to and away from the developing roller 80, and the density is adjusted.
  Since the load F applied to the blade 84 by the rotation of the developing roller 80 is directed away from the rotation fulcrum 82b, chatter vibration does not occur.
[0038]
The rotation shaft (not shown) may be a single shaft common to the rotation fulcrums 82a and 82b in the developing devices 8a, 8b, 8c and 8d. Moreover, it is good also as a structure which provides a rotation axis from the beginning in each rotation fulcrum 82a, 82b, and removes the rotation axis of the rotation fulcrum which is not selected.
In this way, if two rotation fulcrums 82a and 82b are provided and one of them is selected according to the arrangement state of the developing device, the problem of chatter vibration can be suppressed while keeping the parts common. it can. That is, all the parts in the developing devices 8a, 8b, 8c, and 8d shown in FIGS. 3 and 4 are common, and the blade 84 and the rotation change between the developing devices 8a and 8b and the developing devices 8c and 8d. It is only the position of the axis.
Therefore, it is possible to prevent an increase in cost due to the common use in the symmetrical configuration.
[0039]
Next, the shape of the blade 84 and its setting conditions will be described in detail.
Since the tip of the blade 84 on the contact side with the developing roller 80 has a function of scraping ink, sharp edge processing is required. Otherwise, a sensitive performance for changing the ink film thickness instantaneously cannot be expected.
From this viewpoint, as shown in FIG. 5, the edge 84a at the tip of the blade 84 is set to R0.1 or less.
The tip of the blade 84 is formed in a wedge shape with only one side obliquely cut out, and the tip of the wedge-shaped tip is formed as a flat surface 84 b having a slight width in the rotation direction of the developing roller 80. Has been. The width w of the flat surface 84b is set to 0.02 mm or less.
[0040]
  The blade 84 is held by the blade holding means 83 so that the tip of the blade 84 acts in a counter direction with respect to the rotation direction of the developing roller 80. That is, the surface 84c opposite to the obliquely cut-out surface of the wedge-shaped tip is held so as to face the upstream side in the rotation direction of the developing roller 80.
  The surface 84c of the blade 84 uses the surface of the plate as it is, and by doing so, the counter action can be easily and inexpensively obtained on the developing roller 80. When the tip of the blade 84 has a wedge shape with both sides cut away, in order to obtain a counter action with respect to the developing roller 80, the blade 84 must be mounted with a large inclination. Since a bending force acts on the blade 84 when pressed against the developing roller 80, the strength of the blade 84 must be increased, that is, the thickness of the blade 84 must be increased.
  If the wedge shape is formed by one-side processing as described above, it is not necessary to increase the thickness of the blade 84 more than necessary, which is advantageous in terms of processing cost.
  The tip of the blade 84 (flat surface84b) Is rough, streaks are formed on the developing roller 80, and streaks appear in the printed image, leading to a reduction in image quality. For this reason, the flat surface84bThe surface is processed with an accuracy that does not have irregularities of 2 μm or more (Claim 7).
[0041]
As described above, each of the two blade holding plates 87a and 87b has a rotation shaft, but at the contact S with the developing roller 80 of the blade 84 attached to each blade holding plate 87a and 87b. The position of the rotation shaft is set so that the moving direction of the tip of the blade 84 substantially coincides with the radial direction of the developing roller 80 (claim 3).
More specifically, as shown in FIG. 6, the tangential direction E of the rotation trajectory T of the tip of the blade 84 at the contact S between the developing roller 80 and the blade 84 is directed to the approximate rotation center C of the developing roller 80. The positions of the rotation fulcrums 82a and 82b are set. In FIG. 6, the shape of the blade holding means 83 is modified and simplified with priority given to the explanation of the operation.
[0042]
If the moving direction of the tip of the blade 84 does not substantially coincide with the radial direction of the developing roller 80, the developing roller 80 rotates to release the pressure of the blade 84 against the developing roller 80, or conversely, the blade 84 is moved to the developing roller. Eat 80. In such a case, the density adjustment becomes difficult or a new vibration problem different from the chatter vibration occurs.
[0043]
Further, since a load is generated on the blade 84 by the rotation of the developing roller 80, there is a concern that the blade 84 is bent due to the load. As shown in FIG. 7, since the blade 84 has an elongated shape extending in the axial direction of the developing roller 80, the center portion is easily bent into a bow shape having the largest displacement.
When such bending occurs, a gap G is generated between the central portion of the blade 84 and the developing roller 80, and the manner in which the blade 84 contacts the developing roller 80 becomes uneven. In such a state, the ink film thickness on the developing roller 80 becomes non-uniform and density unevenness occurs.
In order to eliminate such a concern, in the present embodiment, a reinforcing member that prevents the blade 84 from being bent due to the rotational load of the developing roller 80 is provided at the center in the longitudinal direction of the blade 84 in the blade holding unit 83. 4).
[0044]
An example in which this reinforcing member is provided will be described with reference to FIG. 8, FIG. 9, and FIG. In each drawing, only the ink reservoir 87 provided with the reinforcing member is shown, and the shape of the ink reservoir 87 is modified and simplified for easy understanding. Moreover, (a) in each figure is sectional drawing in the YY line of (b).
The reinforcing member 96 in FIG. 8 is provided so as to connect the central portions of the blade holding plates 87a and 87b, and is integrally formed therewith.
The reinforcing member 97 in FIG. 9 is provided in an arch shape at the center of the blade holding plates 87a and 87b so as to cover them, and both ends are fixed to the outer surfaces of the blade holding plates 87a and 87b.
The reinforcing members 98 in FIG. 10 are individually provided on the outer surfaces of the central portions of the blade holding plates 87a and 87b, and are fixed thereto.
[0045]
【The invention's effect】
  According to the first aspect of the present invention, since the rotation fulcrum of the blade holding means is provided on the upstream side in the rotation direction of the developing roller from the contact point between the developing roller and the blade, the developing device is arranged regardless of the arrangement state thereof. Chatter vibration between the blade and the developing roller can be suppressed, and the degree of freedom in designing the printing apparatus can be increased.
  In addition, since the blade holding means has two rotation fulcrums where the other is positionally free when one is selected, and either one is selected according to the arrangement state of the developing device, The common use of the parts of the developing device can be promoted, and the manufacturing cost can be reduced.
[0046]
According to the invention of claim 2, since the blade holding means has a function as an ink reservoir member that temporarily stores ink from the ink supply source, a single member also serves as a plurality of functions. Miniaturization and simplification of the configuration can be achieved.
[0047]
According to the third aspect of the present invention, the tangential direction of the rotation locus of the tip of the blade at the contact point between the developing roller and the blade is directed toward the substantially rotation center of the developing roller, so that a stable density can be obtained. Can do.
[0048]
According to the fourth aspect of the present invention, since the reinforcing member is provided to prevent the blade from being bent due to the rotation load of the developing roller, the density change due to the blade deflection can be suppressed.
[0049]
According to the fifth aspect of the present invention, only one side of the tip of the blade is obliquely cut out to form a wedge, the tip of the wedge-shaped tip is formed on a flat surface, and the wedge-shaped tip of the blade is oblique. Since the surface opposite to the notched surface faces the upstream side in the rotation direction of the developing roller, the counter action of the blade with respect to the developing roller can be obtained at a low price and the thickness of the blade is increased. The strength can be obtained without any problem.
[0050]
According to the sixth aspect of the present invention, since the flat surface has a width of 0.2 mm or less, the bending of the blade due to the friction between the blade and the developing roller can be suppressed.
[0051]
According to the seventh aspect of the present invention, since the tip of the blade on the contact side does not have an unevenness of 2 μm or more, it is possible to suppress the formation of streaks in the image and to prevent deterioration in image quality.
[0053]
  Claim8According to the described invention, the blade holding position in the blade holding means is provided at two appropriate positions corresponding to the two rotation fulcrums, and one blade can be shared. A good counter action of the blade with respect to the developing roller can be obtained without increasing.
[0054]
  Claim9According to the described invention, since the blade holding means is driven by the drive source by the screw feed method, the adjustment of the ink film thickness on the developing roller, that is, the density adjustment can be performed with high accuracy.
[0055]
  Claim10According to the described invention, a printing apparatus having the effects of the claims can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic front view of a printing apparatus including a developing device according to an embodiment of the present invention.
FIG. 2 is a detailed view of a primary transfer unit.
FIG. 3 is a schematic front view of the developing device arranged on the left side in FIG. 1;
4 is a schematic front view of the developing device arranged on the right side in FIG. 1;
FIG. 5 is a diagram illustrating a relationship between a tip shape of a blade and a developing roller.
FIG. 6 is a diagram illustrating a blade moving condition with respect to a developing roller.
7A and 7B are diagrams showing a state of bending of the blade, where FIG. 7A is a side view and FIG. 7B is a front view.
FIGS. 8A and 8B are diagrams showing an example in which a reinforcing member is provided, in which FIG. 8B is a schematic plan view, and FIG.
FIGS. 9A and 9B are diagrams illustrating an example in which a reinforcing member is provided, in which FIG. 9B is a schematic plan view, and FIG. 9A is a schematic cross-sectional view taken along line YY in FIG.
10A and 10B are diagrams illustrating an example in which a reinforcing member is provided, in which FIG. 10B is a schematic plan view, and FIG. 10A is a schematic cross-sectional view taken along line YY in FIG.
FIG. 11 is a schematic front view of a printing apparatus in a prior application.
12 is a detailed view of the developing device located on the left side in the printing apparatus shown in FIG.
13 is a detailed view of the developing device located on the right side in the printing apparatus shown in FIG.
14 is a view of the developing device of FIG. 13 as viewed from the back side.
[Explanation of symbols]
2 Version cylinder
5 Heat-sensitive water-repellent printing plate as printing plate
80 Development roller
81 Ink magazine as ink supply source
82a, 82b fulcrum
83 Blade holding means
84 blades
84a flat surface
85 Driving source
96, 97, 98 Reinforcing member
S contact

Claims (10)

A developing roller that supplies ink to a printing plate wound on a plate cylinder, an ink supply source that supplies ink to the developing roller, a blade that uniformly adjusts the ink thickness on the developing roller, and the blade A blade holding means that holds and rotates with respect to the developing roller, and a driving source that drives the blade holding means to bring the blade into and out of contact with the developing roller; Have
A rotation fulcrum of the blade holding means is provided upstream of the contact point between the developing roller and the blade in the rotation direction of the developing roller , and when one of the blade holding means is selected, the other is positionally free. When the rotation direction of the developing roller changes depending on the arrangement state of the developing device, the rotating fulcrum satisfying the corresponding position condition can be selected. Developing device. The developing device according to claim 1,
The developing device, wherein the blade holding means functions as an ink reservoir member that temporarily stores ink from the ink supply source. The developing device according to claim 1 or 2,
2. A developing apparatus according to claim 1, wherein a tangential direction of a rotation locus of a tip of the blade at a contact point between the developing roller and the blade is directed to a substantially rotation center of the developing roller. The developing device according to any one of claims 1 to 3,
A developing device, wherein a reinforcing member for preventing the blade from bending due to a rotational load of the developing roller is provided at a central portion in the longitudinal direction of the blade of the blade holding means. The developing device according to claim 1,
The blade is formed of a plate material, and the tip of the contact point with the developing roller is formed in a wedge shape with only one side obliquely cut off, and the tip of the wedge-shaped tip is the rotation direction of the developing roller The developing device is characterized in that the surface opposite to the obliquely cut-out surface of the wedge-shaped tip is directed upstream in the rotation direction of the developing roller. The developing device according to claim 5, wherein
A developing device characterized in that the flat surface has a width of 0.2 mm or less. The developing device according to any one of claims 1 to 6,
The developing device characterized in that the tip of the blade on the contact side with the developing roller does not have an unevenness of 2 μm or more. The developing device according to claim 1,
The blade holding position of the blade holding means is provided at two appropriate positions corresponding to the two rotation fulcrums, and provided so that one blade can be shared. Developing device. The developing device according to any one of claims 1 to 8 ,
The developing device according to claim 1, wherein the blade holding means is driven by the drive source by a screw feed method . 10. A printing apparatus for supplying ink to a printing plate wound on a plate cylinder by a developing device to form an ink image, and transferring the ink image to a printing paper . among printing apparatus which is a developing device as claimed in.

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