GB2208279A - Printer device using a mimeograph - Google Patents

Abstract

A printer (10) includes a mimeograph - production section (A) where a thermal head (12) perforates the thermosensitive stencil (14) as it is paid out of a roll, and a stencil-cutting section (B), the cut stencil then being wrapped around a print drum (30) automatically. The length of a cut stencil and the length over which a press roller (78) presses paper sheets (38) against the print drum (30) are selected in matching relation to the sensed size of papers used and, optionally to the printing size of the print drum. <IMAGE>

Description

PRINTER DEVICE USING A MIMEOGRAPH The present invention relates to a printer of the type perforating a thermosensitive stencil paid Out from a roll, cutting a given length of the stencil and automatically wrapping it around a print drum, and pressing a paper against the print drum by a press roller to thereby produce a printing.

A prior art printer of the type described is generally made up of a section for perforating a thermosensitive stencil paid out from a roll by a thermal head to make a mimeograph, a section for cutting a given length of the stencil by a cutter, a section for wrapping the cut length of stencil or mimeograph around a cylindrical print drum, and a section for pressing a paper against the periphery of the print drum by a press roller. A printer of the type using a mimeograph and a plurality of interchangeable print drums for implementing multiple colors is also known in the art This type of printer therefore additionally includes a print drum mounting and dismounting section for allowing a print drum to be replaced in a sliding motion.

When a printer having any of the above-described constructions is used to produce a relatively small number of printings, the cost of stencils is usually the most decisive factor with respect to the printing cost per paper. It is therefore desirable that the length of a stencil used to make a single mimeograph be as short as possible. In any of the prior art printers described above, the length of a cut stencil is always the same and predetermined with no regard to the size of a document and that of papers used.This brings about a problem that even when the printing size is as small as that of a postcard, a stencil as large as a stencil adapted for the printing size of B4 or above should be used at the sacrifice of cost Especically, in the case of a printer whose printing ability corresponds to the printing area of A3 size1 a user who desires printings of A4 most often, the user has to use a stencil as great as A3 size despite the actual printing size of A4 every time.

It is therefore an object of the present invention to provide a new and useful printer using a mimeograph capable of producing printings of relatively small size by reducing the length of a stencil to be used automatically, thereby cutting down the cost of stencil.

It is therefore an object of the present invention to provide a mimeograph printer of the kind described in which the cost of stencil per print may be reduced by controlling the stencil length cut for each print according to the size of paper to be printed.

In accordance with the present invention, there is provided a printer using a mimeograph comprising mimeoograph making means for perforating a stencil paid out from a roll to make a mimeograph, cutting means for cutting the stencil, printing means comprising a drum around which the mimeograph is wrapped, ink being supplied from interior of the drum to the mimeograph, paper feeding means for feeding a paper, pressing means comprising a press roller for pressing the paper against the periphery of the drum of the printing means, sensor means for sensing a size of papers loaded in the paper feeding means to produce data representative of the size sensed, and control means for controlling the cutting means and pressing means in response to the data outputted by the sensor moans such that the stencil is cut in a size associated with the size of papers and a length over which the paper is pressed by the press roller is selected on the basis of the size of papers, An arrangement embodying the invention will now be described by way of example with reference to the accompanying drawings, in which:: Fig. 1 is a view schematically showing the overall construction of a printer using a mimeograph to which the preferred embodiments of the present invention are applied; Figs. 2 and 3 are fragmentary developed views each showing a drum of a print drum section in accordance with a first embodiment of the present invention; Fig. 4 is a plan view of a tray which is loaded with a stack of papers; Fig. 5 is a table listing a relationship between the statuses of photosensors and the length of a cut stencil and pressing length; Fig. 6 is schematic block diagram showing a control system in accordance with the first embodiment; Fig. 7 is a front view showing a pressing length changing mechanism in a position before a change; Fig. 8 is a sectional side elevation showing the pressing length changing mechanism in the same position as Fig. 7;; Fig. 9 is a side elvation showing the pressing length changing mechanism in a position after a change; Fig. 10 is a fragmentary developed view of a drum assigned to A4 size in accordance with a second embodiment of the present invention; Fig. 11 is a diagram representative of printing areas of A3 and A4 sizes; Fig. 12 is a block diagram showing a control system in accordance with the second embodiment; Fig. 13 is a fragmentary view showing a pecific construction a device for sensing a drum mounted; Fig. 14 is a front View showing a specific construction of a cam switching mechanism; and Fig. 15 is a section along line XV- XV of Fig. 14 To better understand the present invention, a brief reference will be made to the general construction of a printer using a mimeograph to which the present invention is applied, shown in Fig. 1. As shown, the printer 10 generally comprises a mimeograph making section A, a stencil cutting section B, a print drum section C, a paper feeding section D, a paper pressing section E, a mimeograph outlet section F, and a paper outlet section G.

The mimeograph making section A includes a thermal head 12 for perforating a stencil 14 which is paid out from a roll, and a platen roller 16 for transporting the stencil 14 while pressing it against heating elements of the thermal head 12. The stencil cutting section B includes a cutter 20 which is driven by a drive motor 22 via an eccentric cam 24 to cut a given length of stencil 14 which is fed by a roller pair 26 toward the print drum section C. The print drum section C includes a damper 28 for clamping the leading edge of the stencil 14 which is fed by the roller pair 26, and a perforated cylindrical drum 30 which is rotatable with the stencil 14 being wrapped therearound.Accommodated in the drum 30 are an ink supply roller 32 for supplying ink to the inner wall of the drum 30 and a doctor roller 34 which is parallel to and slightly spaced apart from the ink supply roller 32. The two rollers 32 and 34 define an ink well 36. These components of the print drum section C are combined with an ink container and an ink supply pump to constitute a drum unit. The drum unit is slidable in the axial direction of the drum 30 into and out of a housing of the printer 10. More specifically, a plurality of such drum units are prepared and selectively mounted in the printer 10. For details of a drum mounting and dismounting mechanism, a reference may be made of Japanese Laid-Open Utility Model Publication (Kokai) No. 61-85462.

The paper feeding section D includes a tray 36 which is loaded with a stack of papers 38, a feed roller 40 for feeding the papers 38 one by one from the tray 36, and a roller 42 and a blade 44 cooperating to separate the uppermost paper 38 fed by the roller 40 from the others and drive it toward a feed roller pair 46. The paper pressing section E is implemented by a press roller 48 which presses against the drum 30 the paper 38 which is fed by the feed roller pair 46 in synchronism with the rotation of the drum 30. The press roller 48 is rotated about a shaft 50 by a differential gear and a cam mechanism, .which will be described, to press the paper 38 against the drum 30. The mimeograph outlet section F includes a roller 52 for removing the used stencil or mimeograph 14 from the drum 30, a roller 54 paired with the roller 52 for transporting the stencil 14, and a box 56 for collecting the stencil 14 discharged by the rollers 52 and 54. Further, the paper outlet section G includes a belt 58 for transporting the paper or printing 38, and a tray 60 for collecting the printing 38.

In operation, the thermal head 12 of the mimeograph making section A perforates the stencil 14 in response to an image signal which is fed thereto from a scanner (not shown).

The stencil 14 perforated by the thermal head 12 is clamped at its leading edge by the damper 28 of the print drum section C and, while being continuously perforated by the thermal head 12, sequentially wrapped around the drum 30 which is rotating as indicated by an arrow in Fig. 1. s The amount of feed of the stencil 14 is controlled by the pulse motor 18 which is adapted to drive the platen roller 16. When the stencil 14 is fed by a predetermined amount which is commanded by a controller which will be described, the cutter drive motor 22 is energized to rotate the eccentric cam 24 which in turn moves the cutter 20 to cut the stencil 14. Consequently, the cut length of stencil or mimeograph 14 is fully wrapped around the drum 30.

On the other hand, the uppermost one of the papers 38 stacked on the tray 36 is fed by the roller 40, then surely separated from the others by the separating roller 42 and blade 44, and then driven toward the feed roller pair 46. Rotating in synchronism with the the drum 30, the feed roller pair 46 drives the paper 38 to between the drum 30 and the press roller 48.

The press roller 48 is rotated about the shaft 50 to urge the paper 38 against the drum 30. As a result, ink is transferred to the paper 38 through the perforations of the mimeograph 14 which is retained on the drum 30, forming an image on the paper 38. Then, the paper or printing 38 is transported by the belt 58 to be stacked on the tray 60. The used mimeograph 14 is sequentially removed from the drum 30 by the roller 52 as the drum 30 is rotated and transported by the roller 52 and the coactive roller 54 to be collected in the box 56. Needless to mention, the damper 28 unclamps the leading edge of the mimeograph 14 before the roller 52 separates it.

Hereinafter will be described a first and a second embodiment of the present invention which are applied to the above-described type of printer 10.

Both of the embodiments which will be described are so constructed and arranged as to reduce the cost of stencil when the printer 10 is operated to produce printings of relatively small size, i. e., by reducing the length of a stencil to be used automatically. The key to such construction and arrangement is the timing for cutting a stencil in a given size which matches the size of an original document and, therefore1 the size of papers used, and the timing for causing a press roller to urge the stencil against a drum for a given period of time in associated with the size of the cut length of stenciL A major part of the following description will therefore be directed to a method of determining such timings and means for practicing the method.

First Embodiment In this embodiment, the print drum section C of the printer 10 is implemented by a single drum. More specifically, a single drum is used to produce printings of various sizes.

Fig. 2 shows in a developed view a drum 30A, a mesh screen 62 wrapped around the drum 30A, and a stencil or mimeograph 14 wrapped around the mesh screen 62 and retained by the damper 28. In Fig. 2, a relationship between the drum 30A, the mesh screen 62 and the stencil 14 with respect to the length as measured in an intended direction of paper feed is represented by lengths L, to L6. The printing area or printing ability available with the drum 30A corresponds to A3 size, and the length of an image available with the drum 30A is 410 millimeters. Stated another way, the mimeograph making length L1 of the stencil 14 is 410 millimeters.The pressing length, L e. , the length L2 over which the press roller 48 presses the paper 38 against the drum 30A is about 430 millimeters which is slightly greater than the length L1. The length L3 of a perforated area of the drum 30A is also about 430 millimeters.

Specifically, the cylindrical drum 30A is formed from a sheet metal and provided with a number of apertures 30a in a predetermined range for passing ink therethrough, the apertures 30a each having a diameter of about 0. 5 millimeters. The stencil or mimeograph 14 has a length L, which is equal to the pressing length L2 plus the lengths L5 and L6 of the leading and trailing margins, respectively The lengths L5 and Le are respectively about 80 millimeters and about 20 millimeters and, hence, the overall length Lt of the stencil 14 is about 530 millimeters.

Fig. 3 is a view similar to Fig. 2, showing an alternative case wherein a paper 38 of A4 size is fed in such a position that its lengthwise direction is perpendicular to the direction of feed.

Assuming that the stencil 14 is also of A4 size and fed in the same orientation as the paper 38, the plate making length L'I of the stencil 14 is 200 millimeters while the pressing length L'2 is about 220 millimeters which is slightly greater than the length L'1. While the length L3 of the perforated area 30a of the drum 30A and the length Ls of the leading margin are the same as those of the previous case, the length L'6 of the trailing margin is selected to be about 30 millimeters which is somewhat longer than the length L6. This is because should the trailing margin of the stencil 14 be located in the perforated area L3 of the drum 30A, the trailing edge of the paper 38 would make direct contact with the mesh screen 62 and be smeared thereby.The total length L'4 of the stencil 14 is therefore 330 millimeters.

Referring to Fig. 4, the tray 36 to be loaded with the papers 38 is shown. As shown, the tray 36 is provided with reflection type photosensors 64a, 64b, 64c and 64d for sensing the size of papers 38 as measured in the direction of paper feed. A controller which will be described is supplied with outputs of the photosensors 64a to 64d to estimate the size of papers 38 and select one of the four cutting lengths L, or L', of the stencil 14 and one of the four pressing lengths L2 Or La of the press roller 48.

Fig. 5 lists a relationship between the outputs of the photosensors 64a to 64d and the stencil cutting lengths L4 or L'4 and pressing lengths L2 or L'2. In Fig. 5, circles are each representative of a condition in which the papers 38 have been sensed. It should be noted that the specific numerical values shown in Fig. 5 are only illustrative.

Referring to Fig. 6, a control system is schematically shown in a block diagram. In response to the outputs of the photosensors 64a to 64d, a controller 66 controls the pulse motor 18 1.8 for driving the platen roller 16 and the motor 22 for driving the cutter 20, thereby controlling the stencil cutting length L, or LA. At the same time, the controller 66 actuates a motor 68 for driving a cam which is adapted to drive a differential gear of a pressing cam mechanism, and a solenoid 70 for switching the differential gear, thereby controlling the pressing length. The motor 68 and solenoid 70 will be described in detail later.

As stated above, the illustrative embodiment allows even a printer with which an image area of A3 size is available to print out images on papers 38 whose size is B4 or less by using an appropriate length of stencil 14. This saves the stencil 14 to reduce the printing cost per paper while increasing the number of mimeographs producible from a single roll of stencile 14 and thereby freeing a person from frequent and troublesome operations otherwise needed to replace the rolL In addition, the amount of ink deposited on and discarded together with the used stencil or mimeograph 14 is reduced to in turn reduce the total ink consumption.

A mechanism for changing the pressing length L2 or L'2 is as follows. In the illustrative embodiment, while four different pressing lengths L2 Or L'2 are available, they are the same as each other with respect to the position where pressing begins and different from each other with respect to the position where pressing ends.

Specifically, as shown in Figs. 7 and 8, the mechanism for changing the pressing length L2 or L'2 includes an arm 72 by which the press roller 48 is rotatably supported. The arm 72 is rotatable about the shaft 50 and constantly biased by a spring 74 such that the press roller 48 presses itself against the drum 30. A cam follower 76 is rotatably supported by the other end of the arm 72. As cam plates 78 and 80 are rotated, the cam follower 76 move up and down along the contour of the cam plates 78 and 80 with the result that the pressure of the press roller 48 is selectively applied to the drum 30. The cam plate 80 is rigidly mounted on a shaft 82 and provided with a gear 80a which is rotatable integrally with the cam plate 80.The other cam plate 78 is rotatable about a shank portion of the gear 80a and provided with a cam 68a integrally therewith. The gears 78a and 80a have the same number of teeth as-each other. An idle gear 84 is rotatable about a shaft 86 and held in mesh with both of the the gears 78a and 80a. The idle gear 84 rotates about the shaft 86 while being constantly biased by a spring 88 in one direction. A drive gear 90 is rigidly mounted on the differential gear drive motor 68 and usually held in a position where it does not mesh with the idle gear 84. When the shaft 82 is rotated by a main motor (not shown), the cam plates 78 and 80 are rotated integrally with each other due to the gears 78a and 80a which are meshed with the gear 84. This causes the cam follower 76 to rotate about the shaft 50.

When the size of papers 38 stacked on the tray 36 is changed, the pressing length L2 or L'2 is changed while the main motor is in a halt. Such a condition is shown in Fig. 9.

Specifically, the solenoid 70 is energized by an output signal of the controller 66 to pull an arm 92. As the arm 92 is rotated about a shaft 92, the shaft 86 guided by a slide bearing 96 is moved in the axial direction thereof against the action of the spring 88. Then, the idle gear 84 rotatably mounted on the shaft 86 is also moved to such a position where it meshes with the gear 78a and the drive gear 90 but not with the gear 80a.

In this condition, the controller 66 drives the motor 68 to rotate the gear 78a by a predetermined angle through the idle gear 84.

At this instant, the gear 80a does not rotate. Consequently, the gear 78a is displaced relative to the gear 80a, i. e., the cam plate 78 is displaced relative to the cam plate 80. This changes the overall contour of the cam plates 78 and 80 and thereby the pressing length L2 or L'2. Thereafter, the solenoid 70 is deenergized so that the idle gear 84 is.returned by the spring 88 to its original position where it meshes with the gears 78a and 80a.

As described above, in this particular embodiment, the point where pressing should be ended is changed by changing the amount of deviation of the two cam plates 78 and 80 from each other. In the illustrative embodiment, fine and free adjustment of the cam plates 78 and 80 is promoted due to the use of gears.

While the means for sensing the size of papers 78 has been shown and described as comprising the photosensors 64a to 64d which are provided on the tray 36, it may alternatively be implemented as key means which is provided on a control board.

Specifically, four keys each being assigned to a respective one of different paper sizes may be provided on an operation board and selectively operated by an operator. Then, the controller 66 will select one of four cutting lenths L2 Or L'2 and one of four pressing lengths L2 or L'2 on the basis of the output of any of those keys.

Second embodiment In this particular embodiment, the print drum section C of the printer 10 includes two different kinds of drums, i. e., a drum having a printing ability corresponding to the image area of A3 size and a drum having a printing ability corresponding to the image area of A4 size. Specifically, the print drum section C includes a drum 30A whose printing ability is the same as the drum 30A (Fig. 2) of the first embodiment, and a drum 30B whose printing ability corresponds to the image area of A4 size as shown in Fig. 10. Fig 10 shows in a developed view the drum SOB, a mesh screen 62b wrapped around the drum SOB, and a stencil 14 wrapped around the mesh screen 62b and clamped at its leading edge by the damper 28. The various dimensions shown in Fig. 10 are the lengths as measured in the direction of paper feed as in Figs. 2 and 3. The printing length available with the drum 30B and therefore the mimeograph making length L'1 of the stencil 14 is 200 millimeters. The pressing length L"2 is about 220 millimeters which is slightly greater than the length Low,. The perforated area of the drum 30B has a length L'3 which is also about 220 millimeters. The length Low 5 of the leading margin and the length L116 of the trailing margin are the same as with the drum 30A for size A3 (Fig. 2), i. e. 80 millimeters and 20 millimeters, respectively.

The length L"1 of the stencil 14 is 320 millimeters.

Fig. 11 shows a printing area available with the A3 drum 30A and a printing area available with the A4 drum 30B. It will be seen that a paper 38 of A3 size is fed with its lengthwise direction extending parallel to the direction of paper feed while a paper 38 of A4 size is fed with its lengthwise direction extending perpendicular to the direction of paper feed. A paper 38 of B5 size is also fed with its lengthwise direction extending perpendicular to the direction of paper feed, and the A4 drum 30B is used with such a paper.

Referring to Fig. 12, a control system in accordance with this embodiment is shown. When the printer 10 is loaded with the A3 drum 30A, a drum unit sensor 98 senses it so that a controller 100 controls the pulse motor 18 and the motor 22 according to a program. Consequently, the pulse motor 18 and the motor 22 drive the platen roller and cutter, respectively, such that the stencil 14 is transported and cut at a length Le ofabout 530 millimeters. In the event of printing, the controller 100 drives a motor 102 to switch a cam such that the pressing length L2 becomes about 430 millimeters. On the other hand, when the printer 10 is loaded with the A4 drum 30B, the controller 100 responds to an output of the drum unit sensor 98 by controlling the pulse motor 18 and motor 22 according to the program.At this time, the stencil 14 is cut at a length L"4 of about 320 millimeters. In the event of printing, the controller 100 switcbes the cam to set up a pressing length L"2 of about 220 millimeters.

When the printer 10 with a printing ability corresponding to the image area of A3 size is used to print out images on papers of A4 size or less, the stencil 14 is saved by more than 200 millimeters per mimeograph simply by loading the printer 10 with the A4 drum 30B. This saves the stencil 14 to reduce the printing cost per paper while increasing the number of mimeographs available with a single roll of stencil 14 and thereby eliminating frequent and troublesome operations otherwise needed to replace the roll. In addition, since the amount of ink deposited on and discarded together with the stencil or mimeograph 14 is reduced, the total amount of ink consumed is reduced.

Fig. 13 shows a specific arrangement for sensing the drum units 30A and 30B which are selectively mounted in the printer 10. As shown, the drums 30A and 30B are respectively accommodated in and supported by housings 104A and 104B.

Small magnets 106A and 106B are respectively fitted on the housings 104 and 104B while Hall elements (drum unit sensors) 108A and 108B are mounted on the housing of the copier 10 in such a manner as to face the magnets 106A and 106B, respectively. As shown, the magnet 106A on the A3 drum 30A is located above the magnet 106B on the A4 drum 30B with respect to the radial direction of the drums, and the Hall elements 108A and 108B are positioned in conformity to the magnets 106A and 106B.The turn-on of the upper sensor 108A indicates that the A3 drum 30A is mounted, that of the lower sensor 108B indicates that the A4 drum 30B is mounted, and the turn-off of both the upper sensor 108A and the lower sensor 108B indicates that none of the drums 30A and 30B is mounted.

Referring to Figs. 14 and 15, a specific construction of a cam switching mechanism is shown. As shown, the mechanism includes an arm 72A by which the press roller 48 is rotatably supported. The arm 72A is rotatable about the shaft 50 and constantly biased by the spring 74 such that the press roller 48 presses itself against the drum 30. The cam follower 76 is rotatably supported by the other end of the arm 72A. When a cam 110 is rotated, the cam roller 76 moves up and down on the contour of the cam plate 110 to selectively apply the pressure to the drum 30A (30B).The cam 110 is constituted by two cam plates 110a and 110b which are assigned to the A3 drum 3 0A and the A4 drum 30B, respectively The cam 110 is rigid on a cam shaft 112 with respect to the direction of rotation and slidable on the cam shaft 112 with respect to the direction of thrust (axial direction). A cam switching motor 102 responds to a command from the controller 100 by rotating a screw shaft Then, a slider 116 which is held in mesh with the screw shaft 114 is moved in the axial direction because its rotation is restricted by a shaft 118. As a result, the cam 110 is also moved in the axial direction. In this manner, the cam plates 110a and 110b are selectively brought into contact with the cam follower 76. The cam plate 110a controls the pressing length L2 to 430 millimeters while the cam plate 110b controls the pressing length Lib 2 to 220 millimeters.

In summary, in accordance with the present invention, a stencil can be cut at a particular length which matches the size of paper sheets used and the pressing length of a paper is open to choice. This saves a stencil and thereby cuts down the cost of stencil and other printing costs.

Various modifications will become possible for those skilled in the art after receiving the teachings of the present disclosure without departing from the scope thereof.

Claims (17)

1. A printer using a mimeograph, comprising: mimeograph making means for perforating a stencil paid out from a roll to make a mimeograph; cutting means for cutting the stencil; printing means comprising a drum around which the mimeograph is wrapped, ink being supplied from interior of said drum to the mimeograph; paper feeding means for feeding a paper; pressing means comprising a press roller for pressing the paper against periphery of said drum of said printing means; sensor means for sensing a size of papers loaded in said paper feeding means to produce data representative of the size sensed; and control means for controlling said cutting means and said pressing means in response to the data outputted by said sensor means such that the stencil is cut in a size associated with the size of papers and a length over which the paper is pressed by said press roller is selected on the basis of said size of papers.

2. A printer as claimed in claim 1, wherein said mimeograph making means comprises a thermal head for perforating the stencil, a platen roller for transporting the stencil while pressing said stencil against said thermal head, and a pulse motor for driving said platen roller.

3. A printer as claimed in claim 2, wherein said cutting means comprises a cutter for cutting the stencil perforated, a cutter drive motor for driving said cutter, and eccentric cam means interposed between said cutter drive motor and said cutter such that said cutter cuts the stencil in a predetermined size.

4. A printer as claimed in claim 3, wherein said pressing means further comprises changing means for changing a pressing length over which said press roller presses the paper against the periphery of said drum.

5. A printer as claimed in claim 4, wherein said changing means comprises an arm member rotatable about a shaft, said press roller being rotatably mounted on one end of said arm member and a cam follower being rotatably mounted on the other end of said arm member, a pressing cam mechanism comprising a cam member engaged with said cam follower of said arm member and a differential gear for changing the pressing length of said press roller, a gear drive motor for driving said differential gear, and a gear switching solenoid for switching a meshing condition of said differential gear.

6. A printer as claimed in claim 5, wherein said control means controls said differential gear drive motor and said differential gear switching solenoid to change the pressing length.

7. A printer as claimed in claim 3, wherein said control means controls said pulse motor and said cutter drive motor to change the size in which the stencil is to be cut.

8. A printer as claimed in claim 1, wherein said printing means is selectively loaded with a plurality of drums one at a time.

9. A printer as claimed in claim 8, further comprising drum mounting dismounting means for mounting and dismounting said drum.

10. A printer as claimed in claim 9, further comprising, drum sensor means for sensing a printing ability of said drum mounted to produce data representative of the printing ability, said control means controlling said cutting means and said printing means such that the stencil is cut in a predetermined size and the printing length is set up each in associated with said data.

11. A printer as claimed in claim 10, wherein said mimeograph making means comprises a thermal head for perforating the stencil, a platen roller for transporting the stencil while pressing said stencil against said thermal head, and a pulse motor for driving said platen roller.

12. A printer as claimed in claim 11, wherein said cutting means comprises a cutter for cutting the stencil perforated, a cutter drive motor for driving said cutter, and eccentric cam means interposed between said cutter drive motor and said cutter such that said cutter cuts the stencil in a predetermined size.

13. A printer as claimed in claim 12, wherein said pressing means further comprises changing means for changing a pressing length over which said press roller presses the paper against the periphery of said drum.

14. A printer as claimed in claim 13, wherein said changing means comprises an arm member rotatable about a shaft and carrying said press roller at one end and a cam follower at the other end each in a rotatable manner, a cam mechanism comprising a cam member which is engaged with said cam follower, and a cam switching motor for switching said cam member of said cam mechanism.

15. A printer as claimed in claim in claim 14, wherein said control means controls said cam switching motor to change the pressing length.

16. A printer as claimed in claim 12, wherein said control means controls said pulse motor and said cutter drive motor to change the size in which the stencil is to be cut.

17. A printer using a mimeograph substantially as described with reference to Figures 1 to 9, or Figure 1 together with Figures 10 to 15 of the accompanying drawings.