Abstract: A multicolor printing method using a plurality of ink drums each being loaded with a respective master and a system therefore are disclosed. A plurality of removable ink drums replaceable with each other are fed with respective masters by fixed master feeding devices smaller in number than ink drums via the replacement of the drums and are used for printing. The method and system of the present invention are low cost and enhance downsizing and accurate registration between the masters.

Abstract: A support structure for a blanket cylinder of an offset printing press includes: a first eccentric bearing that is rotatably supported by frames of the offset printing press; a second eccentric bearing that is rotatably supported by the first eccentric bearing so as to rotatably support an shaft of a blanket cylinder; a printing pressure adjustment device that rotates the first eccentric bearing relative to the frames, thereby adjusting a clearance between an impression cylinder and a blanket cylinder; and a throw-on device that rotates the second eccentric bearing relative to the first eccentric bearing, thereby performing throw-on and throw-out operations. In the thus arranged support structure, a throw-on distance of the throw-on device is variable.

Abstract: A stencil printing ink container comprises a cylinder, an area of one end of the cylinder, which area is other than an ink discharge opening section, being closed with an end wall, the other end of the cylinder being open, and a piston, which undergoes a sliding movement in an axial direction of the cylinder and along its inner circumferential surface. The ink container is filled with ink having a viscosity of at most 7.5 Pa·s with respect to a shear rate of 100 sec−1 and at 23° C. and satisfies a specific relationship among an inside radius of the cylinder, an inside radius of the ink discharge opening section, a length of the ink discharge opening section, a weight of the ink filled in the ink container, a sliding movement starting load of the piston, and the viscosity of the ink.

Abstract: A stencil printer of the present invention includes a print drum for wrapping a master therearound, a master making and conveying section for perforating a stencil paid out from a stencil roll while conveying it to thereby produce the master, a master stocking section for stocking the master being conveyed by the master making and conveying section, and a roller pair for conveying the master out of the master stocking section. A movable master guide selectively guides the stencil paid out from the stencil roll to the master stocking section or the roller pair. A stretching member adjoins the print drum and is movable between a contact position where it contacts the stencil present on the print drum to thereby exert a stretching force on the master and a released position where the former is released from the latter. The stretching member and movable master guide are interlocked to each other.

Abstract: A hybrid stencil printing apparatus comprises: a stencil-making/printing unit configured to perforate a stencil sheet corresponding to a desired image, to wind the stencil sheet around an outer peripheral surface of a print drum, and to transfer a printing medium to the print drum with pressure and the printing medium is printed; an other-method image-formation unit configured to print the printing medium transferred on the same transfer passage as the stencil-making/printing unit according to a different printing method from the stencil-making/printing unit; and an image-formation unit selection-unit configured to input an original digital image, to determine a attributes of each image portion of the inputted original digital image, and to allocate each image portion selectively to the stencil-making/printing unit or the other-method image-formation unit based on the determination result.

Abstract: A stencil printing machine includes a drum which is rotatable and has an outer peripheral wall formed by an ink impermeable member and in which a stencil sheet is mounted on a surface of the outer peripheral wall. An ink supply device has an ink supply unit at a printing position upstream of a maximum printing area of the outer peripheral wall of the drum and supplies ink on the surface of the outer peripheral wall from the ink supply unit. A pressure roller presses a fed print medium onto the outer peripheral wall.

Abstract: A stencil printer of the present invention perforates, or cuts, a thermosensitive stencil with a thermal head to thereby make a master. The stencil printer includes a stencil distinguishing device for automatically identifying the kind of the stencil or a master setting device for allowing the operator of the printer to set the kind of the stencil. An adjusting device selects, among master making conditions experimentally determined beforehand, a master making condition matching with information output from the stencil distinguishing device or the stencil setting device. The operator can easily change the master making condition in accordance with the kind of a stencil to use.

Abstract: A stencil printing machine (10) having plural printing drums and a control method thereof can perform correctly a stencil printing process so that even if one or more errors occur in a printing drum (1 or 2) which is not used in the current printing process, another printing drum (1 or 2) is used.

Abstract: A stencil printing machine having an exfoliation suction apparatus including a case having a guide plate at its upper face, a suction force generating portion provided at the case and an exfoliation suction port provided at one end portion of the guide plate for constituting suction force for exfoliating print sheet from a printing drum by suction force by the suction force generating portion in which the exfoliation suction port is arranged to be proximate to a press roller orthgonally to a center line of a squeegee roller intersecting with an axis line of the printing drum and on a lower side of a reference line passing through a position of bringing the press roller and into press contact with the printing drum.

Abstract: A support for a cylindrical screen in a rotation screen printing apparatus. The apparatus has two sides. The support includes a side flange on each of the two ends of the apparatus; an intermediate ring resiliently supported by each side flange; a turnbuckle rotatable rotatably disposed in each intermediate ring; a stencil ring disposed in each turnbuckle. Whereby the screen is received at each end of the apparatus through the stencil rings in a turnbuckle, so that when subjected to a load, the screen is able to pivot and be displaced in an axial direction relative to the flange at least within predetermined limits.

Abstract: A stencil printer of the present invention includes a master making section for perforating a master, which includes a porous support and a thermoplastic resin film, in accordance with image data to thereby make a master and wraps the master around a print drum to thereby effect printing. The stencil printer includes a cavity sensor for sensing the condition of cavities existing in the porous support of the stencil. A controller identifies the kind of the stencil by determining the condition of the cavities in accordance with information output from the cavity sensor, so that stable print quality is insured without regard to a difference in cavity ratio between the lots of stencils.

Abstract: A stencil printing machine includes a drum which is rotatable and has an outer peripheral wall formed by an ink impermeable member and in which a stencil sheet is mounted on a surface of the outer peripheral wall. An ink supply device has an ink supply unit at a printing position upstream of a maximum printing area of the outer peripheral wall of the drum and supplies ink on the surface of the outer peripheral wall from the ink supply unit. A pressure roller presses a fed print medium onto the outer peripheral wall.

Abstract: A printer with a duplex printing capability of the present invention includes a printing section. In a duplex print mode, the printing section prints either one of a first and a second image formed in a master side by side on the front side of a first sheet. A path selector steers the first sheet coming out of the printing section toward an auxiliary tray. The printing section prints either one of the first and second images on the front side of a second sheet while refeeding means again feeds the first sheet to the printing section to thereby form either one of the first and second images on the reverse side of the first sheet. The path selector steers the first and second sheets toward a sheet discharging section and the auxiliary tray, respectively.

Abstract: A printer capable of printing a multicolor image with a single pass of a paper or similar recording medium includes a plurality of print drums. Drum drive gears each are mounted on a particular print drum such that the print drum is replaceable. The print drums are interlocked to each other by rotatable members including relay gears meshing with the drum drive gears, timing pulleys fixed to the relay gears, a timing belt, and pulleys for adjustment. Each rotatable member has teeth the number of which is selected such that the number of rotations of the rotatable member to occur in a single period of the print drums is an integral multiple of the number of rotations of the print drums.

Abstract: A hybrid stencil printing apparatus comprises: a stencil-making/printing unit configured to perforate a stencil sheet corresponding to a desired image, to wind the stencil sheet around an outer peripheral surface of a print drum, and to transfer a printing medium to the print drum with pressure and the printing medium is printed; an other-method image-formation unit configured to print the printing medium transferred on the same transfer passage as the stencil-making/printing unit according to a different printing method from the stencil-making/printing unit; and an image-formation unit selection-unit configured to input an original digital image, to determine a attributes of each image portion of the inputted original digital image, and to allocate each image portion selectively to the stencil-making/printing unit or the other-method image-formation unit based on the determination result.

Abstract: A printing control system for a printer includes the same number of one-page tasks as the number of printing papers which can be simultaneously present on the printing path of the printer at the maximum and a main control task which starts one of the one-page control means which are free each time a printing paper is supplied. Each of the one-page control tasks controls printing action on the corresponding printing paper from the step of supplying the corresponding printing paper to the step of discharging the corresponding printing paper and is made free when the printing action on the corresponding printing paper is successfully finished or when an error is detected during the printing action on the corresponding printing paper.

Abstract: A stencil printer of the present invention includes a print drum around which perforated part of a stencil or master is to be wrapped. A master making section make a master and includes a cutter for cutting the stencil paid out from a roll. A master discharging section removes the master wrapped around the print drum and then discharges it. A deciding device determines, on the turn-on of a power supply, whether or not the power supply has been turned off during an interval between the time when the stencil paid out from the roll starts being perforated and the time when the cutter cuts the stencil. When the deciding device determines that the power supply has been turned off during the above interval, the master discharging section discharges the master present on the print drum.

Abstract: A multicolor printing method using a plurality of ink drums each being loaded with a respective master and a system therefore are disclosed. A plurality of removable ink drums replaceable with each other are fed with respective masters by fixed master feeding devices smaller in number than ink drums via the replacement of the drums and are used for printing. The method and system of the present invention are low cost and enhance downsizing and accurate registration between the masters.

Abstract: A paper jam detection system for a folding machine includes an interval signal generator for generating an interval signal which assumes ON and OFF levels alternately according to cutting intervals of a cutting cylinder; a signature detection mechanism including reflection plates each having a light reflection surface and being arranged circumferentially at an outer circumferential surface portion of a jaw cylinder and a photoelectric sensor adapted to generate a reflection plate detection signal upon detection of the reflection plate; and a control unit for outputting a paper jam signal on the basis of the interval signal and the reflection plate detection signal.

Abstract: A stencil printer is linked with a non-stencil printer. A number of copies to be printed is set. Working mode of the stencil printer is set to a stencil making mode or an ink transfer mode. A stencil is made when the working mode of the stencil printer is set to the stencil making mode and ink is transferred to a printing paper through the stencil when the stencil printer is set to the ink transfer mode. When the number of copies set is not smaller than a predetermined threshold value, the stencil printer is used, and when the number of copies is smaller than the predetermined threshold value, the non-stencil printer is used. Switching between the stencil printer and the non-stencil printer is inhibited when the working mode of the stencil printer is the ink transfer mode.

Abstract: An image display medium 1 includes a film body 2 having a number of microscopic film pieces 2a. The film body 2 is sandwiched between a supporting member 3 having receiving spaces 5 and a cover member 4. The image display medium 1 is brought into contact with a rotary drum 26 of an image generating apparatus. Corresponding to a perforated image in a stencil sheet 101 attached to the rotary drum 26, the respective microscopic film pieces 2a of the film body 2 are selectively absorbed to the cover member 4 or partitions 5a of the supporting member 3.

Abstract: Machine to simultaneously hot-press, print, flock imprint and brush, especially suitable for the production of printed and flocked fabrics, including a fabric reel, a fabric accumulator, a pre-treatment device, a first continuous oven drier, a hot-pressing device, a first cooling device, a printing device including rotary rollers for applying color printing paste and flock adhesive paste, a flock dispensing device, a flock embossing device, a second continuous oven drier for thermally fixing the flock adhesive and color printing pastes, a second cooling device, a brushing battery, a roller for winding, and a cutter.

Abstract: A printing control apparatus for controlling a stencil printing machine (50, 100), wherein a stencil sheet, which is made on the basis of image data, is wound around a printing drum (25; 125, 126) with which a print sheet (34; 141) is held in pressured contact to perform a stencil printing operation, provides the stencil printing machine with image data representative of an image to be reproduced as an object, and printing order information representative of a page order in which the printing operation is performed using image data, an ink color for the printing drum to be used, and a timing in which one printing drum is replaced with another one. In accordance with the printing order information, the ink color contained in image data is detected and an order for each page to be printed is determined on the basis of a user's print request to execute the printing operation according to the page order and to reduce the number of times the printing drum is replaced with.

Abstract: A stamp of liquid-exuding type has a multiple-seal-faced assembly adapted for stamping with selected one of these multiple faces, preferably for stamping with multiple colors.

Abstract: A printing unit includes two screen-printing cylinders and two transfer cylinders that cooperate with the screen-printing cylinders and which define a printing gap or nip. At least one of the screen-printing cylinders has a screen surface and an interior doctor blade. A support element is provided for handling radially outwardly directed pressure exerted by the doctor blade on the screen surface in one section of the screen surface.

Abstract: A printing form for transferring free-flowing printing ink to a printing material to be printed includes a body having a surface formed with a multiplicity of openings coverable by printing ink; a multiplicity of gas-containing cavities formed in the body, the cavities, respectively, terminating in the openings, respectively, at the surface of the body; and devices assigned to the cavities, respectively, for producing a vacuum therein for sucking printing ink covering the openings of the cavities into a region adjacent to the openings of the cavities, respectively, when a vacuum is produced by devices in the cavities, respectively; an ink transferring device including the printing form; and a method of producing the printing form.

Abstract: A printer capable of printing a multicolor image with a single pass of a paper or similar recording medium includes a plurality of print drums. Drum drive gears each are mounted on a particular print drum such that the print drum is replaceable. The print drums are interlocked to each other by rotatable members including relay gears meshing with the drum drive gears, timing pulleys fixed to the relay gears, a timing belt, and pulleys for adjustment. Each rotatable member has teeth the number of which is selected such that the number of rotations of the rotatable member to occur in a single period of the print drums is an integral multiple of the number of rotations of the print drums.

Abstract: A printer capable of printing a multicolor image with a single pass of a paper or similar recording medium includes a plurality of print drums. Drum drive gears each are mounted on a particular print drum such that the print drum is replaceable. The print drums are interlocked to each other by rotatable members including relay gears meshing with the drum drive gears, timing pulleys fixed to the relay gears, a timing belt, and pulleys for adjustment. Each rotatable member has teeth the number of which is selected such that the number of rotations of the rotatable member to occur in a single period of the print drums is an integral multiple of the number of rotations of the print drums.

Abstract: A printer of the present invention includes drive pulleys each being mounted on a particular print drum.

Abstract: A stencil printing machine is provided as including first and second printing drums 25 and 26 carrying thereon respective screens30, a press drum 27 located in close proximity to the printing drums and a stencil making unit 9. In a control method, the stencil making unit 9 supplies a perforated stencil sheet 11a onto a selected printing drum 25 and a non-perforated stencil sheet 11b onto a non-selected printing drum 26, wherein a print sheet 41 clamped to the press drum 27 is transferred along an outer periphery of the press drum 27 to allow the perforated stencil sheet of the first printing drum 25 to transfer printing ink with a first color to the print sheet 41 while the non-perforated stencil sheet mounted onto the second printing drum prevents printing ink to be transferred to the print sheet 41.

Abstract: A stencil disposal box is detachably provided to a stencil printing machine main body, and used stencil sheets are stored therein when the stencil disposal box is mounted to the stencil printing machine main body. An opening, through which a stencil sheet is conveyed, is formed on the stencil disposal box. The stencil disposal box includes a stencil disposal box main body for storing the conveyed stencil sheets, a sweeping member rotatively provided so as to move between an innermost position approximately adjacent to an inner surface of the stencil disposal box main body and a sweeping position located more adjacently to the opening side than the innermost position, and an operation lever portion, which can operate the movement of the sweeping member. This operation lever portion can be operated while gripping a handle portion.

Abstract: On each of plural printing drums (25, 26) in a stencil printing machine (1), a stencil sheet (11) made corresponding to printing data is rolled. The machine (1) for a stencil printing process, in which a printing paper is pressed on each printing drum and the used stencil sheet is disposed, has a mode designation section (101) and a controller (102). The section (101) designates whether or not a stencil printing process is performed for plural printing information including common printing data. The control section (102) controls the stencil making process, the stencil disposing process, and the stencil printing process for the printing information. When the printing information includes common printing data, the controller (102) controls the printing drum on which the stencil sheet for the common printing data is rolled so that the stencil making and disposal processes are not performed.

Abstract: An image display medium 1 includes a film body 2 having a number of microscopic film pieces 2a. The film body 2 is sandwiched between a supporting member 3 having receiving spaces 5 and a cover member 4. The image display medium 1 is brought into contact with a rotary drum 26 of an image generating apparatus. Corresponding to a perforated image in a stencil sheet 101 attached to the rotary drum 26, the respective microscopic film pieces 2a of the film body 2 are selectively absorbed to the cover member 4 or partitions 5a of the supporting member 3.

Abstract: A screen-printing device for printing a substrate, comprising at least one printing station having a removable stencil, a printing-medium feed and a squeegee device, a cleaning unit which can be displaced to and fro in the stencil at least in the longitudinal direction, feed means for feeding cleaning liquid into the stencil, and discharge means for removing printing medium and/or cleaning liquid from the stencil. The discharge means comprise a suction nozzle for sucking printing medium and/or cleaning liquid out from the stencil, which nozzle is arranged on the displaceable cleaning unit and can be moved to and fro in the longitudinal direction inside the stencil together with this unit.

Abstract: A stencil printing machine and a control method is provided wherein first and second printing drums 25 and 26 are rotatably supported in close proximity to an outer periphery of a press drum 27 at positions spaced by a given angle, wherein outer circumferential peripheral walls of the first and second printing drums 25 and 26 carry stencil clamping bases 28, respectively, and inner press rollers 33 are located inside the printing drums 25 malid 26, respectively. During printing operation, the printing drums 25 and 26 are rotated with a rotational phase angle of 180 degrees relative to the press drum and, at termination of printing operation, the printing drums 25 and 26 are stopped at respective stationary rest positions which are out of ink stain zones of respective printing drums.

Abstract: A printer including drive pulleys each being mounted on a particular print drum. Each of the print drums has a pitch circle diameter and a number of teeth related to each other as: d/z<1 where d denotes the pitch circle diameter (mm) and z denotes the number of teeth.

Abstract: When a stencil sheet (M) is wound around an outer peripheral surface of a rotary cylindrical drum (24) in accordance with a rotation thereof, a leading end of the stencil sheet (M) is retained by a clamp plate (51) provided on the rotary cylindrical drum (24), and the stencil sheet (M) is conveyed while being guided by upper and lower guide plates (45, 46) and nipped between the lower guide plate (46) and a supporting member (48) attached to an underside of a swinging member (47). At this stage, predetermined tension is applied to the stencil sheet (M) by an urging force of the swinging member (47) to thereby prevent occurrence of wrinkles on the stencil sheet (M).

Abstract: A user PC 120 for controlling a stencil printing machine 1, having a plurality of exchangeable printing drums, wherein respective printing drums are mounted with respective perforated stencil sheets which are formed by a stencil-making processing section 104 on the basis of image data, and a print sheet is held in press contact with the plural printing drums to perform a stencil printing process with first and second stencil-printing processing sections 105, 106 is disclosed as having a registering function to register printing ink colors to be used for printing with the respective printing drums by enabling reading-in of a printer driver and to store useable ink color information, a function to produce display data to display contents of the ink-color designating information produced by the designating section for the respective printing drums.

Abstract: A synchronous drive arrangement for a printer of the present invention includes a timing belt passed over drive pulleys each being mounted on a particular print drum. The timing belt is made up of two narrow belt parts produced by dividing a single belt. Assuming that the belt parts have n teeth each, one of the belt parts is shifted from the other belt part by one-half of the number of teeth n. The belt parts are so positioned as to cancel each other's eccentricity component during rotation. The arrangement reduces synchronization errors ascribable to the eccentricity of the timing belt while preserving the low-cost configuration of timing belt connection.

Abstract: A printer with a duplex printing capability of the present invention includes a printing section. In a duplex print mode, the printing section prints either one of a first and a second image formed in a master side by side on the front side of a first sheet. A path selector steers the first sheet coming out of the printing section toward an auxiliary tray. The printing section prints either one of the first and second images on the front side of a second sheet while refeeding means again feeds the first sheet to the printing section to thereby form either one of the first and second images on the reverse side of the first sheet. The path selector steers the first and second sheets toward a sheet discharging section and the auxiliary tray, respectively.

Abstract: A printing drum (2), to which a stencil sheet having subjected to a stencil making process is attached, can be attached to and removed from a printer main body (1). A nonvolatile memory (25) is provided in the printing drum. The number of print products is stored in the nonvolatile memory as “Information on the use” of the printing drum. A control device (5) of the printer main body reads out “Information on the use” from the nonvolatile memory and stores them in a RAM (12) when the printing drum is attached to the printer main body. Subsequently, when printing is performed, information on the number of print products is updated. When the printing drum is removed from the printer main body, “Information on the use” is updated and written into the nonvolatile memory.

Abstract: A master making and feeding device for a printer includes a first conveying section and a second conveying section. When the first conveying section is perforating a stencil or after it has perforated a stencil, conveyance drive means drives the second conveying section at a preselected timing in order to feed the leading edge of the stencil to a print drum. At this instant, the conveyance drive means drives the second conveying section such that it conveys the stencil at a higher speed than the first conveying section. The device is capable of reducing a period of time necessary for the leading edge of the perforated stencil to be fed to the print drum and therefore a first print time.

Abstract: A stencil discharge apparatus for a stencil printing machine has a discharge box for storing a predetermined amount of stencil sheets after being peeled off from a printing drum so as to discharge the stencil sheets. The stencil discharge apparatus includes a compressing device for compressing the stencil sheets discharged into the discharge box through motion of a compressing plate; a compressing pressure sensing device for sensing and outputting a compressing pressure of the compressing means; a moving amount sensing means for sensing and outputting an amount of motion of the compressing plate; and a control device for calculating a storing amount of the stencil sheets in the discharge box on the basis of sensing a predetermined pressure through the compressing pressure sensing device and an amount of motion sensed by the moving amount sensing device.

Abstract: In a stencil printer system, a stencil is made by the use of master material unrolled from a stencil material roll and is wound around a printing drum by clamping the leading end of the stencil on the printing drum and rotating the printing drum while the stencil is once slackened on the way to the printing drum. There is provided along the stencil conveyance path between the stencil material roll and the printing drum a tension blade which is pressed against the stencil to apply back tension to the stencil when the stencil is run by the printing drum and the tension blade is formed so that the stencil undergoes force which tends to displace outward the stencil from the central portion in the direction of width of the stencil.

Abstract: An ink supply roll is disposed inside a printing drum of a stencil printer and supplies ink to the inner peripheral surface of the printing drum. At least the surface layer of the ink supply roll is formed of a nonmetal material which is not larger than 100° in contact angle and not larger than ±5% in swelling ratio to an ultraviolet-curing monomer.

Abstract: In a printing machine, a tip end of a print sheet 22, which is transferred from a paper feed section 5 synchronously with rotation of a printing drum 16 and a pressure drum 17, is clamped by a sheet clamp section 21 at a rotation clamp position upstream of a press portion on which the printing drum 16 and the pressure drum press each other. The print sheet 22 thus clamped is transferred along an outer peripheral surface of the pressure drum 17 and pressed against a stencil sheet on the press portion. Then, printing is done. The printing machine is provided with a sheet clamp guide member 30 guiding the tip end of the print sheet 22, which is transferred from the sheet feed section 5, to a position on which the print sheet 22 is abutted on a sheet abutment face 21a of the sheet clamp section 21 located at the rotation clamp position.

Abstract: To prevents a displacement of a screen mask accompanying with a movement of a squeegee and an oxidization of a printing agent, a printing agent sweeping drum (1) has closed both end portions, has a supporting shaft (2) inserted to a center portion thereof, has a lower end portion partly opened, is made rotatable with respect to the supporting shaft, oscillates along a moving direction of the squeegee via a movement of the supporting shaft (2), moves downward at a movement starting end position, moves upward at a terminal end position, and rotates at a predetermined angle in an opposite direction at a predetermined timing at the starting end position and the terminal end position, a squeegee (4) inclined at a predetermined angle and moving upward and downward at a predetermined timing being arranged within the printing agent sweeping drum 1, a squeegee (10) and a printing agent extruding plate (11) being attached to a lower end of the squeegee holder (4) and a nitrogen gas (17) being charged into the printing

Abstract: A stencil printing machine including a plurality of printing drums which are arranged to be spaced apart from each other such that respective axis lines thereof are respectively made horizontal and respective peripheral walls of which are wound with perforated stencil sheet, a stencil making unit for perforating the stencil sheet and a moving mechanism for supporting the stencil making unit to be movable relative to the respective printing drums.

Abstract: Printing pressure to be applied to a press roller (18) is obtained by a pressure applying spring (33) and an adjustable spring (41), and the adjustable spring (41) is extended or contracted by a tensile-force varying mechanism, thereby rendering the printing pressure variable. Accordingly, in cases such as where the viscosity of ink has changed due to a temperature change, and the contact time of a printing sheet (P) with respect to a rotary cylindrical drum (14) or a stencil sheet (M) has changed due to a change in the printing speed, it is possible to stabilize printed image performance by adjusting the density of an image which is printed. In addition, a strong tensile force for stabilizing the printing pressure by the press roller (18) is dispersed between the pressure applying spring (33) and the adjustable spring (41), and the adjustable spring (41) is extended or contracted.

Abstract: A stencil printing machine and a method carrying out a printing operation are disclosed wherein a print sheet is transferred through between an upstream printing drum and a press roller in a pressured state to transfer ink onto an upper surface of the print sheet and is then transferred through between a downstream printing drum and a press roller in a pressured state to transfer ink onto the other surface of the print sheet to perform a both sides printing operation. A printing-drum drive escape mechanism is located to shift the downstream printing drum to a drive escape position to interrupt rotation of the printing drum while retaining the press roller in a separated position away from the shifted printing drum in such a manner that the printing operation under such a condition in a one side printing mode is executed.