JP4422983B2 - Stencil printing machine - Google Patents

Description

【００２９】
表１において、節約長▲１▼は印刷用紙のサイズに合わせてカットされたマスタの、Ａ３サイズマスタ長に対する１版あたりの節約長であり、節約長▲２▼は印刷用紙のサイズ一定のままマスターロール全て使いきった場合にＡ３サイズマスタ長に対する節約長である。
その節約長▲２▼の場合、節約される版数を示してある。マスタは一ロール当たり約２５０版取れるものとして計算している。使用する印刷用紙が常に１種類であるユーザも実際に存在するが、一般的にマスターロール中で様々な種類の印刷用紙を使用すると思われるため、実際に節約される版数は必ずしもこの表１の通りではない。
【００３０】
図７は、ドラムカバー５１が未使用時に重なり合ってマスタクランパ１２下部に収納されている状態を示している。使用時には、図８に示すように、カバー駆動手段８０によりカバー５１Ａ、５１Ｂ、５１Ｃが順次引き出される構造になっている。
各カバー５１Ａ、５１Ｂ、５１Ｃは、それぞれ両端部にスライド係合部５１ａ、５１ｂ、５１ｃを有している。各スライド係合部５１ａ、５１ｂ、５１ｃは、スライド係合部５１ａを代表して説明すると、図９（裏面側から見た図）に示すように、印刷ドラム１の周方向に延びる溝５１ａ−１と、該溝５１ａ−１の引き出し方向（矢印Ｓ方向）後端部に形成された係合爪５１ａ−２を有している。
係合爪５１ａ−２は、カバー５１Ａの裏面側において、重なり合うカバー５１Ｂの厚みよりも若干大きく突出した垂直部５１ａ−２−１と、溝５１ａ−１の幅ｄよりも長い水平部５１ａ−２−２を有し、水平部５１ａ−２−２が相手側を押えることにより重なり状態が維持される。他のスライド係合部５１ｂ、５１ｃにおいても同様である。
カバー５１Ａが引き出され、係合爪５１ａ−２がカバー５１Ｂの溝５１ｂ−１の引き出し方向先端に当接することにより、カバー５１Ｂの引き出しが始まる。カバー５１Ｂが引き出されると、続いてカバー５１Ｃの引き出しが始まる。
【００３１】
図１０乃至図１２に基づいて、カバー駆動手段８０の構成及び動作を説明する。印刷ドラム１にはセクターギア５７が設けられており、ステッピングモータ６１に取り付けられた駆動ギア６０が中継ギア５９を介してセクターギア５７に連結されている。
セクターギア５７は印刷ドラム１の回転支軸１１を中心に回転運動を行い、セクターギア５７に一体に形成された引き出しアーム７１の先端に保持されたドラムカバー５１を引き出すことができるようになっている。
セクターギア５７には、ドラムカバー５１を収納した（折り畳んだ）状態のホームポジションを検知するためのセンサ５８が設けられている。中継ギア５９は軸８１の先端部に固定されており、軸８１にはフランジ８３が固定されている。軸８１は図示しない側板に位置固定されたフランジ８２にスライド自在に挿通され、フランジ８２とフランジ８３には圧縮スプリング６３が固定されている。軸８１には圧縮スプリング６３により常に矢印Ｌ方向に引っ張るテンションが掛けられ、ドラムカバー５１を引き出す時以外は駆動ギア６０及びセクターギア５７と中継ギア５９との連結は解除されている。
【００３２】
ギア連結時には、ソレノイド６４がオンされる。ソレノイド６４がオンされてその可動軸６４ａが吸引されると、軸６５を支点とするギア押しアーム６２が矢印Ｒ方向に回動し、中継ギア５９がセクターギア５７と駆動ギア６０に噛み合う方向に押し出されて各ギアが連結される。セクターギア５７、ステッピングモータ６１、駆動ギア６０、中継ギア５９、引き出しアーム７１、圧縮スプリング６３、フランジ８２、フランジ８３、軸８１、軸６５、ギア押しアーム６２等によりカバー駆動手段８０が構成されている。
【００３３】
ドラムカバー５１の引き出し制御は、図１３に示す制御手段８４によってなされる。制御手段８４には操作パネル８５からの各設定情報が入力されるとともに、印刷用紙のサイズを検知する光センサ４０、４１、ドラムカバー５１のホームポジションを検知するためのセンサ５８等からの検知情報が入力される。
制御手段８４はこれらの入力情報に基づいて、ステッピングモータ６１やソレノイド６４等を制御する。
制御手段８４は、ＣＰＵ、ＲＯＭ、ＲＡＭ、Ｉ／Ｏインターフェース等を含むマイクロコンピュータであり、孔版印刷装置のメインコントローラが兼ねることができるものである。
制御手段８４は、光センサ４０、４１の検知情報又は操作パネル８５からの入力情報、あるいは外部接続機器からの入力情報に基づいて印刷用紙のサイズを判断すると、印刷ドラム１の印刷可能領域のうち、上記サイズに応じて切断されるマスタで覆われない部分を被覆するためにカバー駆動手段８０を制御する。
【００３４】
ＲＯＭには印刷用紙のサイズとドラムカバー５１の引き出し量（厳密にはステッピングモータ６１のステップ数）との関係がデータテーブルとして予め記憶されており、印刷用紙のサイズに対応したステップ数を選択してステッピングモータ６１を制御する。
印刷用紙のサイズに対応したドラムカバー５１による被覆がなされると、印刷用紙のサイズに対応してカットされたマスタが印刷ドラム１の外周面に巻装され、印刷が行われる。
本実施形態では印刷ドラム１における開孔部の露出部分が存在しないため、圧胴２０による印圧は印刷ドラム１の印刷領域全体に亘って掛けられる。従って途中で印圧を抜くようなカム機構や制御は不要となる。プレスローラを用いた場合でも同様である。
印刷が終了すると、ドラムカバー５１はカバー駆動手段８０によりその引き出し量を元に戻され、折り畳み状態に収納される。次の印刷での印刷用紙のサイズが判明するまでドラムカバー５１の引き出し状態を維持し、サイズが異なった場合のみホームポジションに戻して対応する引き出し量を得る制御としてもよい。
【００３５】
ドラムカバー５１の材質としては、非インキ通過性、撥インキ性を得るために、ポリエチレン系樹脂やポリプロピレン系樹脂等が望ましい。全体的特性としては、シャッター構造における引き出し、収納動作に係る耐久性を維持できるとともに、印刷ドラム１の外周面に沿う柔軟性を有するものが望ましい。
ドラムカバー５１を構成する単位カバー（５１Ａ、５１Ｂ、５１Ｃ）自体が剛性を有していても、各単位カバーの周方向の幅を小さくしてカバー数を多くすれば全体的柔軟性（印刷ドラム１の周面への追随性）が得られる。
【００３６】
上記実施形態では、印刷用紙のサイズに応じて自動的にドラムカバー５１を引き出して被覆する制御構成としたが、例えば操作パネル８５上でユーザ（オペレータ）がドラムカバー５１の引き出し量を設定するとともに、スイッチを押してカバー駆動手段８０を駆動する構成としてもよい（第２の実施形態）。
また、ドラムカバー５１を使用するかどうかをユーザが選択することができるようにしてもよい（第３の実施形態）。
例えば図１４に示すように、印刷用紙がＡ３サイズよりも小さい場合は、操作パネル８５の液晶表示部６７に、ドラムカバー使用推奨のメッセージが表示されるようにする。ユーザが選択した選択肢部分は反転表示されて選択されていることが明示される。図１４ではドラムカバー５１を「使用する」が選択されていることを示している。
また、印刷用紙を横にセットできるようなサイズ、例えばＡ４やＢ５等は縦にセットするよりも横にセットした方がマスタの節約となるので、その旨を伝えるメッセージが液晶表示部６７に表示されるようにしてもよい。図１４では、「用紙をＡ４横にするとマスタ節約ができます」旨のメッセージを表示した状態を示している。図１４において、符号６６は各種キーの配置部を示している。
【００３７】
図１５及び図１６に基づいて第４の実施形態を参考例として説明する。
上記各実施形態では、自動的にあるいは半自動的にドラムカバーを被覆する構成としたが、本実施形態では定型サイズのドラムカバーを手動で印刷ドラムにセットすることを特徴としている。
印刷ドラム１の外周面における軸方向端部には、ドラムカバーを保持するための細幅の面状ファスナー６８ａ、６８ｂが周方向に固定されている。これに対応して定型サイズのドラムカバー６９の内面にも面状ファスナー７０が一対設けられている。
本実施形態では、ドラムカバー６９は印刷用紙の種類（サイズ）に対応した個数が用意され、印刷用紙のサイズに応じてその都度着脱交換する。
ドラムカバー６９は印刷用紙の種類だけ揃えず、例えば種類を限定してＡ４横用のみとしてもよい。この場合は、Ａ４横サイズより小さい印刷用紙を用いる場合でもマスタ長さはＡ４横の長さである３２０ｍｍで必ず使用されるようにすればよい。
上記実施形態と同様に、ドラムカバー６９は樹脂などの柔軟性に富む素材から構成されており、印刷ドラム１の曲率に一致するように手動で固定することで印刷ドラム１の外周に設置される。
ドラムカバー６９の着脱手段として面状ファスナーを例示したが、これに限定する趣旨ではなく、着脱機能が得られる範囲で種々のものを採用できる。
【００３８】
上記いずれの実施形態においても、マスタカット長を印刷ドラム１の開孔部長より短くした場合、印刷ドラム１の開孔部をドラムカバーで被覆することにより、開孔部からのインキ吐出による押圧部に対するインキ転写汚れを防止することができるので、押圧範囲は印刷用紙の種類によらず、ドラムカバーによる被覆部を含め、印刷ドラム１の印刷領域全体（Ａ３サイズ対応）の押圧範囲から変更する必要が無くなる。
【００３９】
【発明の効果】
本発明によれば、記録媒体のサイズに応じたマスタカットによってマスタの無駄な消費を削減できるとともに、ドラムカバーの被覆により印刷ドラムの開孔部の露出を防止できる。開孔部の露出防止により印圧を印刷ドラムの印刷可能領域全体に亘って掛けることができ、特別な印圧制御構成や交換用印刷ドラムを必要としない。
一般に、マスタの印刷ドラムに接する面には和紙層が形成されており、インキを取り込んで保持しやすいが、ドラムカバーを非インキ通過性又は撥インキ性の材料で形成すれば、インキ付着量はマスタの場合に比べて少なく、排版時に捨てられるインキ量を低減できる。
【００４１】
本発明によれば、ドラムカバーによる印刷ドラム上のマスタで覆われない部分の被覆を労力を要することなく容易に行うことができる。
【００４２】
本発明によれば、ドラムカバーによる印刷ドラム上のマスタで覆われない部分の被覆を労力を要することなく自動的に行うことができる。
【００４３】
本発明によれば、ドラムカバーによる印刷ドラム上のマスタで覆われない部分の被覆を自動的に且つ高精度に行うことができる。
【００４４】
本発明によれば、印刷に供されない無駄なインキの発生を低減できる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態における孔版印刷装置の概要正面図である。
【図２】記録媒体のサイズの種類とサイズ検知手段との関係を示す平面図である。
【図３】給紙台における印刷用紙側端を保持するための側板を示す斜視図である。
【図４】側板の移動構成を示す底面側から見た斜視図である。
【図５】記録媒体のサイズに応じて側板を移動させる摺動子ケースを示す図である。
【図６】ドラムカバーを有する印刷ドラムの側面図である。
【図７】シャッター構造のドラムカバーの収納状態を示す図である。
【図８】ドラムカバーを全長引き出した状態を示す図である。
【図９】ドラムカバーを構成する各カバーの係合構成を示す図である。
【図１０】ドラムカバーとカバー駆動手段の位置関係を示す概要正面図である。
【図１１】カバー駆動手段の概要平面図である。
【図１２】カバー駆動手段の要部斜視図である。
【図１３】制御ブロック図である。
【図１４】第３の実施形態における操作パネルの概要平面図である。
【図１５】第４の実施形態における印刷ドラムの側面図である。
【図１６】第４の実施形態における印刷ドラムに対するドラムカバーの取り付け構成を示す図である。
【符号の説明】
１ 印刷ドラム
２ マスタ
３ 記録媒体としての印刷用紙
５１、６９ ドラムカバー
８０ カバー駆動手段
８４ 制御手段[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stencil printing apparatus for performing printing by winding a pre-made master around the outer peripheral surface of a printing drum. In place Related.
[0002]
[Prior art]
In the stencil printing apparatus, an outer peripheral surface of a porous printing drum (plate cylinder) having an ink supply means inside a master (stencil paper) perforated and made based on original reading data or data received from an external connection device The recording medium such as a printing sheet is pressed by a pressing member such as a press roller that is wound around the printing drum and is provided so as to be able to contact with and separate from the outer peripheral surface of the printing drum.
By the pressing (printing pressure) by the pressing member, the ink supplied to the inner peripheral surface of the drum oozes out through the drum opening portion and the master punching portion, and is transferred to the printing paper to form a printed image.
[0003]
It is known that when printing a small number of copies in a stencil printing apparatus, it is the cost of the master that has the greatest influence on the printing cost per sheet. In a conventional stencil printing apparatus, the length of the master used for printing is constant according to the size of the printing drum, and when printing on paper that is less than the maximum printing area of the printing drum, the master of the portion not involved in printing Was wasted.
For example, when printing on A4 size paper with a printing drum having a fine aperture area that can be printed on A3 size paper, the master does not actually make the master plate even though it is an A4 size image area. It had to be used in A3 size, resulting in great waste. At the same time, there is a problem that the amount of ink that is not used for printing that adheres to the master and is discarded at the time of discharging is increased, resulting in great economic waste.
[0004]
In order to cope with such a problem, Japanese Patent Laid-Open No. 1-224783 proposes a method of changing the length of the master according to the size of the paper to be used. However, even in this case, when the printing drum is left after printing, if the opening portion of the printing drum is exposed, there is a risk of clogging of the opening portion due to surrounding dust, etc. The last plate is designed to use a master having a size that can cover the opening portion, that is, a master having the maximum size.
Since the master of the maximum size is used for the last version, the reduction in economic waste associated with the master length was not satisfactory.
[0005]
When printing is performed using a master shorter than the printable area (opening portion) of the printing drum, if printing is performed in the original pressing range, printing pressure is applied to the portion not covered by the master, and the exposed printing drum Ink is ejected from the opening, and the ink is transferred to a press roller or an impression cylinder, which is a pressing means, and stains are generated.
In order to prevent this, it is necessary to incorporate a mechanism for changing the printing pressure range in accordance with the master cut length, as disclosed in JP-A-9-169154.
In addition, there are printing drums in which the aperture area is narrowed to A4 size or B4 size for master saving, and as disclosed in Japanese Patent Laid-Open No. 1-18683, the types of printing drums installed in the printing apparatus There is also proposed a method for controlling the master length by recognizing this and replacing the printing drum.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 1-18683
[Patent Document 2]
Japanese Patent Laid-Open No. 9-169154
[Patent Document 3]
JP-A-1-24783
[0007]
[Problems to be solved by the invention]
In the method of controlling the pressing range (printing pressure range), a special mechanism such as a cam for quickly removing the printing pressure is required, and the position of the cam is adjusted according to the size of the printing paper, or a plurality of cams It was inconvenient because it was necessary to select and control.
In the method of replacing the printing drum according to the size of the printing paper, the replacement work is troublesome, and the problem of storage and management of the printing drum that is not mounted on the apparatus main body and the cost increase cannot be avoided.
In other words, in the past, while reducing the cost by changing the master length in accordance with the size of the printing paper, there has been a tendency that the human labor and the economic burden for the countermeasures become larger.
[0008]
The present invention can reduce wasteful consumption of a master, reduce the amount of ink discarded at the time of discharging, and does not require a special printing pressure control configuration or replacement printing drum. Set The main purpose is provision.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a pre-printed master is wound around the outer peripheral surface of a printing drum, ink is supplied from the inside of the printing drum, and a recording medium is pressed against the printing drum. In the stencil printing apparatus for performing printing, a drum cover for covering a portion of the printable area of the printing drum that is not covered with the master whose circumferential length is cut according to the size of the recording medium Have The drum cover has a structure in which a plurality of covers are connected in a foldable manner by moving in the horizontal direction, and is provided so as to be able to be drawn out from a predetermined position along the outer peripheral surface of the printing drum, and pulls out the drum cover. Cover drive means It is characterized by having.
[0010]
In invention of Claim 2, in the stencil printing apparatus of Claim 1, Control means for controlling the cover driving means to change the pull-out amount of the drum cover according to the size of the recording medium. It is characterized by that.
[0011]
In the invention of claim 3, claim 1 is provided. Or 2 In the stencil printing apparatus described above, the drum cover Is non-ink-permeable or ink-repellent It is characterized by having.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
First, an outline of the stencil printing apparatus according to the present embodiment will be described with reference to FIG. A roll-shaped master roll 10 is rotatably held in the plate-making unit 19. The fed master 2 is pressed against a heating element (not shown) of the thermal head 17 by a platen roller 9 and read by a scanner (not shown). Perforated according to the original pattern.
The master 2 thus made is cut by the cutter unit 4 and conveyed toward the master clamper 12 of the printing drum 1 by the plate feeding roller 5. The conveyed master 2 is clamped at the tip by a master clamper 12 and is wound around the outer peripheral surface by the rotation of the printing drum 1. The platen roller 9 is rotationally driven by the motor 6, whereby the master 2 is conveyed to the plate feeding roller 5 side. The upper blade of the cutter unit 4 is always urged upward by an urging member (not shown), and is pressed downward by an eccentric member 8 that is rotationally driven by a motor 7.
[0020]
The printing drum 1 is rotated clockwise by a driving device (not shown). The printing drum 1 includes a stainless steel porous cylindrical support 48 having minute openings, and a mesh screen layer 49 wound around one or more layers on the outer peripheral surface of the porous cylindrical support 48. .
Inside the printing drum 1, there are provided an ink roller 13 that rotates in the same direction as the printing drum 1, and a doctor roller 15 that is slightly spaced from the outer periphery of the ink roller 13. A wedge-shaped facing space formed between the ink roller 13 and the doctor roller 15 forms an ink reservoir 16. Ink is supplied dropwise to the ink reservoir 16 from a hole (not shown) of the shaft pipe 11 that also serves as the rotation support shaft of the printing drum 1.
By the rotation of the ink roller 13 and the doctor roller 15, the ink 14 in the ink reservoir 16 is supplied to the outer peripheral surface of the ink roller 13 while the layer thickness is regulated. The ink supplied to the outer peripheral surface of the ink roller 13 is supplied to the inner peripheral surface of the printing drum 1.
[0021]
A pressure drum 20 as a pressing unit is provided below the printing drum 1 at a position facing the ink roller 13. The impression cylinder 20 presses the printing paper 3 as a recording medium against the master 2 wound around the outer circumferential surface of the printing drum 1 at a printing pressure portion that is a position on the outer circumferential surface of the printing drum 1 facing the ink roller 13. It has an action and consists of a roller-like rotating body. In addition to the impression cylinder 20, a press roller may be used as the pressing means. In this embodiment, a case where the impression cylinder 20 is used will be described.
In order to avoid collision with the clamper 12 on the printing drum 1, the impression cylinder 20 has a part of the outer periphery that is concave and flat, and has a D-shape when viewed from the axial direction. A gripping claw 21 that holds the leading end of the printing paper 3 is provided so as to be openable and closable at one end in the circumferential direction (the rear side in the rotation direction) of the flat portion. The gripping claw 21 is opened at a predetermined timing by a cam (not shown), is closed after the printing paper 3 is added, holds the printing paper 3 on the outer circumferential surface of the impression cylinder 20, and is provided near the outer circumferential portion of the impression cylinder 20 when printing is completed. The paper is opened again at the position of the paper discharge claw 29, and the front end of the print paper 3 is opened so that the front end of the print paper 3 is sent to the paper discharge conveyance device 35 via the paper discharge claw 29.
[0022]
On the downstream side in the transport direction of the printing drum 1, a paper discharge claw 29 for peeling the print paper 3, a paper discharge transport device 35 for transporting the peeled print paper 3, and a print transported by the paper discharge transport device 35. A paper discharge tray 36 for loading and storing the paper 3 is provided. The paper discharge transport device 35 has a configuration for transporting the print paper 3 while adsorbing it by the negative pressure action of air.
On the upstream side of the printing drum 1 in the conveyance direction, a printing paper storage unit including an elevator-type paper feed table 31 that can store printing papers of different sizes is provided. The paper feed table 31 is provided with optical sensors 40 and 41 as size detecting means for detecting the size of the stored printing paper.
The optical sensor 40 is arranged at a position where the leading edge of the printing paper can be detected, and the optical sensor 41 is arranged behind the optical sensor 40 at a predetermined interval behind (upstream) in the transport direction (paper feeding direction).
The size of the stored printing paper 3 can be identified when only the optical sensor 40 detects the presence of the printing paper 3 and when the optical sensor 40 and the optical sensor 41 detect it. The position of the paper feed tray 31 is controlled by a driving device (not shown) so that the uppermost position of the stacked printing paper 3 is given an appropriate pressing force that can always be conveyed by the calling roller 30. ing.
[0023]
FIG. 2 is a schematic diagram in which various printing papers are arranged on the paper feed tray 31, and a white arrow pointing to the left indicates the conveyance direction of the printing paper. Printing paper of A6 size to A3 size can be stacked on the paper feed tray 31.
In the figure, “A6 portrait” refers to the case where an A6 size printing paper is arranged with its longitudinal direction coincided with the transport direction, and “A4 landscape” refers to the short direction and transport direction of the A4 size print paper. This is a case where they are arranged to match.
In accordance with such a display method, “A6 portrait”, “B5 landscape”, “A5 portrait”, “A4 landscape”, “B5 portrait”, “A4 portrait”, “B4 portrait”, “ There are eight types of printing paper types and arrangements of “A3 portrait”.
In the present embodiment, the optical sensor 40 is provided in the vicinity of the left end of the paper feed table 31. The optical sensor 41 is disposed outside the position A4h, which is a horizontal dimension of A4, from the left end of the paper feed table 31 and inside the position B5v, which is a vertical dimension B5, from the left end of the paper feed table 31. Yes.
[0024]
As shown in FIG. 3, side plates 42 and 42 ′ for holding the printing paper side edge are provided on the paper feed table 31 so as to be movable in the printing paper width direction (direction perpendicular to the transport direction). As shown in FIG. 4, the side plates 42 and 42 'can be slid in a direction perpendicular to the conveyance direction of the printing paper by a mechanism including a rack 43 and a pinion 44, and the optimum width according to the size. It can hold printing paper.
The rack 43 is integrally provided with a slider case 45. As shown in FIG. 5, a slider 46 that interlocks with the horizontal movement of the side plate 42 ′ and a paper size detection plate 47 are provided in the rack 43. Is arranged. Each terminal of the paper size detecting plate 47 is connected by the movement of the slider 46 accompanying the movement of the side plate 42, and the combination signal is discriminated by a processing device (not shown) to detect the width of the printing paper. it can.
In this way, the size of the printing paper is determined by the optical sensors 40 and 41, the slider 46 and the paper size detecting plate 47. The detected size information of the printing paper is input to the control unit 84 described later.
[0025]
FIG. 6 shows the printing drum 1 as viewed from the side. The porous cylindrical support 48 is fixed to flanges 50 and 50 ′ disposed at both ends of the rotation support shaft 11. The length of the opening (printable area) of the printing drum 1 is set to about 430 mm which is about 10 mm longer than 420 mm of the A3 paper vertical dimension in the case of a drum corresponding to A3 size. In this embodiment, the case where the printing drum 1 corresponding to A3 size is used will be described.
In FIG. 6, reference numeral 51 denotes a drum cover for covering a portion of the printable area of the printing drum 1 that is not covered with the master 2 whose length in the circumferential direction is cut according to the size of the printing paper 3. Is shown.
As shown in FIGS. 7 and 8, the drum cover 51 has a shutter structure in which a plurality of covers 51A, 51B, and 51C are connected in a foldable manner by horizontal movement. As shown in FIG. Is provided on the outer peripheral surface of the master damper 12 opposite to the master winding side or on the lower surface of the master clamper 12 so as to be drawn along the outer peripheral surface of the printing drum 1. The drum cover 51 is pulled out by the cover driving means 80. 7 shows a state in which the drum cover 51 is stored, and FIG. 8 shows a state in which the drum cover 51 is pulled out to the maximum.
[0026]
When the size of the printing paper 3 loaded on the paper feed tray 31 is determined and the size is smaller than the A3 size, the drum cover 51 for covering the opening portion of the printing drum 1 is pulled out, and the mesh screen layer 49 is pulled out. The portion not covered with the master 2 is covered from above.
When A3 size printing paper is stacked on the paper feed tray 31, the drum cover 51 is not pulled out, and the length of the opening portion of the printing drum 1 remains 430 mm. It is covered with 50 mm to be 380 mm.
Similarly, the drum cover 51 is covered so that the opening length is 310 mm for A4 length, 270 mm for B5 length, 220 mm for A4 width and A5 length, 190 mm for B5 width, and 160 mm for A6 length.
[0027]
After the opening is covered with the drum cover 51, a master whose cut length is controlled according to the determined printing paper type is wound. For example, when printing on A3 size printing paper, the length to which the master is pressed is 430 mm, which is the length of the opening, but the master length is the leading edge margin and trailing edge margin in addition to the pressed length. It becomes the thing which added the minute. The entire master length is about 530 mm in order to secure about 80 mm as the front end margin and about 20 mm as the rear end margin.
Since the leading edge margin and the trailing edge margin need to be constant regardless of the master cut length, the master length for each printing paper is 480 mm for B4 length, 410 mm for A4 length, 370 mm for B5 length, A4 width, A5 length is 320 mm, B5 width is 290 mm, and A6 length is 260 mm.
Since the master length is shortened according to the size of the printing paper, the master is saved accordingly. Table 1 summarizes the aperture area, master length, saving length, and saving plate number for each printing paper size.
[0028]
[Table 1]

[0029]
In Table 1, the saving length (1) is the saving length per plate of the master cut according to the size of the printing paper with respect to the A3 size master length, and the saving length (2) is the same as the printing paper size. This is the saving length for the A3 size master length when all the master rolls are used up.
In the case of the saving length (2), the version number to be saved is shown. It is calculated that the master can take about 250 plates per roll. Although there is actually a user who always uses one type of printing paper, it is generally considered that various types of printing paper are used in the master roll. It is not street.
[0030]
FIG. 7 shows a state in which the drum cover 51 is overlapped and stored in the lower part of the master clamper 12 when not in use. At the time of use, as shown in FIG. 8, the cover 51 A, 51 B, 51 C is sequentially pulled out by the cover driving means 80.
Each cover 51A, 51B, 51C has slide engaging portions 51a, 51b, 51c at both ends. Each slide engagement portion 51a, 51b, 51c will be described as a representative of the slide engagement portion 51a. As shown in FIG. 9 (viewed from the back side), a groove 51a− extending in the circumferential direction of the printing drum 1 is provided. 1 and an engaging claw 51a-2 formed at the rear end of the groove 51a-1 in the pulling-out direction (arrow S direction).
The engaging claw 51a-2 has a vertical portion 51a-2-1 protruding slightly larger than the thickness of the overlapping cover 51B and a horizontal portion 51a-2 longer than the width d of the groove 51a-1 on the back surface side of the cover 51A. -2 and the horizontal portion 51a-2-2 presses the other side to maintain the overlapping state. The same applies to the other slide engaging portions 51b and 51c.
The cover 51A is pulled out, and the engaging claw 51a-2 comes into contact with the leading end in the pulling direction of the groove 51b-1 of the cover 51B. When the cover 51B is pulled out, the drawing out of the cover 51C starts.
[0031]
Based on FIG. 10 thru | or FIG. 12, the structure and operation | movement of the cover drive means 80 are demonstrated. The printing drum 1 is provided with a sector gear 57, and a drive gear 60 attached to the stepping motor 61 is connected to the sector gear 57 via a relay gear 59.
The sector gear 57 rotates around the rotation support shaft 11 of the printing drum 1 so that the drum cover 51 held at the tip of a drawer arm 71 formed integrally with the sector gear 57 can be pulled out. Yes.
The sector gear 57 is provided with a sensor 58 for detecting the home position in which the drum cover 51 is housed (folded). The relay gear 59 is fixed to the tip of the shaft 81, and a flange 83 is fixed to the shaft 81. The shaft 81 is slidably inserted into a flange 82 fixed to a side plate (not shown), and a compression spring 63 is fixed to the flange 82 and the flange 83. The shaft 81 is always tensioned in the direction of the arrow L by the compression spring 63, and the connection of the drive gear 60, the sector gear 57 and the relay gear 59 is released except when the drum cover 51 is pulled out.
[0032]
When the gear is connected, the solenoid 64 is turned on. When the solenoid 64 is turned on and the movable shaft 64a is sucked, the gear pushing arm 62 having the shaft 65 as a fulcrum rotates in the direction of arrow R, and the relay gear 59 is engaged with the sector gear 57 and the drive gear 60. Each gear is connected by being pushed out. The cover driving means 80 is constituted by the sector gear 57, the stepping motor 61, the driving gear 60, the relay gear 59, the pull-out arm 71, the compression spring 63, the flange 82, the flange 83, the shaft 81, the shaft 65, the gear pushing arm 62, and the like. Yes.
[0033]
The pull-out control of the drum cover 51 is performed by the control means 84 shown in FIG. Each setting information from the operation panel 85 is input to the control unit 84, and detection information from the optical sensors 40 and 41 for detecting the size of the printing paper, a sensor 58 for detecting the home position of the drum cover 51, and the like. Is entered.
The control means 84 controls the stepping motor 61, the solenoid 64, etc. based on these input information.
The control means 84 is a microcomputer including a CPU, ROM, RAM, I / O interface, and the like, and can also serve as a main controller of the stencil printing apparatus.
When the control unit 84 determines the size of the printing paper based on the detection information of the optical sensors 40 and 41, the input information from the operation panel 85, or the input information from the external connection device, The cover driving means 80 is controlled so as to cover the portion not covered with the master cut according to the size.
[0034]
In the ROM, the relationship between the size of the printing paper and the drawing amount of the drum cover 51 (strictly, the number of steps of the stepping motor 61) is stored in advance as a data table, and the number of steps corresponding to the size of the printing paper is selected. The stepping motor 61 is controlled.
When the drum cover 51 corresponding to the size of the printing paper is covered, the master cut according to the size of the printing paper is wound around the outer peripheral surface of the printing drum 1 and printing is performed.
In the present embodiment, since there is no exposed portion of the opening in the printing drum 1, the printing pressure by the impression cylinder 20 is applied over the entire printing area of the printing drum 1. Therefore, a cam mechanism or control for releasing the printing pressure in the middle is not necessary. The same applies when a press roller is used.
When printing is completed, the drum cover 51 is returned to its original drawing amount by the cover driving means 80 and stored in a folded state. The drum cover 51 may be pulled out until the size of the printing paper in the next printing is determined, and only when the size is different, control may be performed to return to the home position and obtain a corresponding drawing amount.
[0035]
The material of the drum cover 51 is preferably a polyethylene resin or a polypropylene resin in order to obtain non-ink-passability and ink repellency. As an overall characteristic, it is desirable that the durability in relation to the drawer and storage operations in the shutter structure can be maintained, and the flexibility along the outer peripheral surface of the printing drum 1 is desirable.
Even if the unit covers (51A, 51B, 51C) constituting the drum cover 51 have rigidity, if the width in the circumferential direction of each unit cover is reduced to increase the number of covers, the overall flexibility (printing drum 1) can be obtained.
[0036]
In the above embodiment, the drum cover 51 is automatically pulled out and covered in accordance with the size of the printing paper. However, for example, the user (operator) sets the pull-out amount of the drum cover 51 on the operation panel 85. The cover driving means 80 may be driven by pressing a switch (second embodiment).
In addition, the user may be able to select whether or not to use the drum cover 51 (third embodiment).
For example, as shown in FIG. 14, when the printing paper is smaller than A3 size, a drum cover use recommendation message is displayed on the liquid crystal display section 67 of the operation panel 85. The option part selected by the user is highlighted to clearly indicate that it is selected. FIG. 14 shows that “use” of the drum cover 51 is selected.
In addition, since the master can save the size of the printing paper that can be set horizontally, for example, A4 or B5, rather than setting it vertically, a message to that effect is displayed on the liquid crystal display unit 67. You may be made to do. FIG. 14 shows a state in which a message “Master saving can be achieved by placing paper on A4 side” is displayed. In FIG. 14, reference numeral 66 denotes an arrangement part for various keys.
[0037]
A fourth embodiment based on FIGS. 15 and 16 As a reference example explain.
In each of the above embodiments, the drum cover is covered automatically or semi-automatically. However, the present embodiment is characterized in that a fixed-size drum cover is manually set on the printing drum.
Narrow planar fasteners 68 a and 68 b for holding the drum cover are fixed in the circumferential direction at the axial end of the outer peripheral surface of the printing drum 1. Correspondingly, a pair of planar fasteners 70 are also provided on the inner surface of the standard-sized drum cover 69.
In this embodiment, the drum cover 69 is prepared in a number corresponding to the type (size) of the printing paper, and is attached and detached each time according to the size of the printing paper.
The drum cover 69 is not limited to the type of printing paper. For example, the type of the drum cover 69 may be limited and used only for A4 landscape. In this case, even when printing paper smaller than the A4 horizontal size is used, the master length may be always used with the A4 horizontal length of 320 mm.
Similar to the above-described embodiment, the drum cover 69 is made of a flexible material such as resin, and is installed on the outer periphery of the printing drum 1 by being manually fixed so as to match the curvature of the printing drum 1. .
Although a planar fastener is illustrated as an attachment / detachment means for the drum cover 69, the present invention is not limited to this, and various types can be adopted as long as an attachment / detachment function can be obtained.
[0038]
In any of the above-described embodiments, when the master cut length is shorter than the opening portion length of the printing drum 1, the opening portion of the printing drum 1 is covered with the drum cover, so that the pressing portion by ink discharge from the opening portion is covered. Ink transfer stains can be prevented, so the pressing range must be changed from the pressing range of the entire printing area of the printing drum 1 (corresponding to A3 size), including the cover portion of the drum cover, regardless of the type of printing paper. Disappears.
[0039]
【The invention's effect】
The present invention According to ,Record The master cut according to the size of the recording medium can reduce unnecessary consumption of the master, and the cover of the drum cover can prevent the opening portion of the printing drum from being exposed. By preventing the opening from being exposed, printing pressure can be applied over the entire printable area of the printing drum, and no special printing pressure control configuration or replacement printing drum is required.
Generally, a Japanese paper layer is formed on the surface that contacts the printing drum of the master, and it is easy to take in ink and hold it, but if the drum cover is made of a non-ink-permeable or ink-repellent material, the ink adhesion amount will be Compared to the master case, the amount of ink discarded during the plate removal can be reduced.
[0041]
The present invention According to , De The portion of the printing drum not covered by the master on the printing drum by the ram cover can be easily applied without requiring labor.
[0042]
The present invention According to , De The portion of the printing drum not covered by the master on the printing drum by the ram cover can be automatically applied without requiring labor.
[0043]
The present invention According to , De The ram cover can automatically and accurately cover the portion of the printing drum that is not covered by the master.
[0044]
The present invention According to ,mark Generation of wasted ink that is not used for printing can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic front view of a stencil printing apparatus according to a first embodiment of the present invention.
FIG. 2 is a plan view showing the relationship between the type of size of a recording medium and size detection means.
FIG. 3 is a perspective view showing a side plate for holding a printing paper side edge in a paper feed tray.
FIG. 4 is a perspective view showing the moving configuration of the side plate as seen from the bottom side.
FIG. 5 is a diagram showing a slider case that moves a side plate according to the size of a recording medium.
FIG. 6 is a side view of a printing drum having a drum cover.
FIG. 7 is a diagram illustrating a storage state of a drum cover having a shutter structure.
FIG. 8 is a view showing a state in which the drum cover is pulled out full length.
FIG. 9 is a diagram showing an engagement configuration of each cover constituting the drum cover.
FIG. 10 is a schematic front view showing a positional relationship between a drum cover and cover driving means.
FIG. 11 is a schematic plan view of cover driving means.
FIG. 12 is a perspective view of the main part of the cover driving means.
FIG. 13 is a control block diagram.
FIG. 14 is a schematic plan view of an operation panel according to a third embodiment.
FIG. 15 is a side view of a printing drum according to a fourth embodiment.
FIG. 16 is a diagram illustrating a configuration for attaching a drum cover to a printing drum according to a fourth embodiment.
[Explanation of symbols]
1 Printing drum
2 Master
3 Printing paper as a recording medium
51, 69 Drum cover
80 Cover drive means
84 Control means

Claims (3)

In a stencil printing apparatus that winds a master made on the outer peripheral surface of a printing drum, supplies ink from the inside of the printing drum and presses a recording medium against the printing drum to perform printing,
A drum cover for covering a portion of the printable area of the printing drum that is not covered with a master whose circumferential length is cut according to the size of the recording medium ;
The drum cover has a structure in which a plurality of covers are connected in a foldable manner by moving in the horizontal direction, and is provided so as to be able to be pulled out from the predetermined position along the outer peripheral surface of the printing drum. A stencil printing apparatus comprising a driving means . In the stencil printing apparatus according to claim 1,
A stencil printing apparatus comprising control means for controlling the cover driving means so as to change the amount of the drum cover pulled out in accordance with the size of the recording medium . In the stencil printing apparatus according to claim 1 or 2 ,
The stencil printing apparatus, wherein the drum cover has non-ink-passing property or ink repellency .

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